.github/workflows/pages.yml

@@ -0,0 +1,40 @@
+name: Dokka publication
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Checkout the repo
+        uses: actions/checkout@v2
+      - name: Set up JDK 11
+        uses: actions/setup-java@v1
+        with:
+          java-version: 11
+      - name: Cache gradle
+        uses: actions/cache@v2
+        with:
+          path: ~/.gradle/caches
+          key: ubuntu-20.04-gradle-${{ hashFiles('*.gradle.kts') }}
+          restore-keys: |
+            ubuntu-20.04-gradle-
+      - name: Cache konan
+        uses: actions/cache@v2
+        with:
+          path: ~/.konan
+          key: ${{ runner.os }}-gradle-${{ hashFiles('*.gradle.kts') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+      - name: Build
+        run: |
+          ./gradlew dokkaHtmlMultiModule --no-daemon --no-parallel --stacktrace
+          mv build/dokka/htmlMultiModule/-modules.html build/dokka/htmlMultiModule/index.html
+      - name: Deploy to GitHub Pages
+        uses: JamesIves/github-pages-deploy-action@4.1.0
+        with:
+          branch: gh-pages
+          folder: build/dokka/htmlMultiModule

.github/workflows/publish.yml

@@ -12,7 +12,7 @@ jobs:
       name: publish
     strategy:
       matrix:
-        os: [macOS-latest, windows-latest]
+        os: [ macOS-latest, windows-latest ]
     runs-on: ${{matrix.os}}
     steps:
       - name: Checkout the repo

CHANGELOG.md

@@ -4,17 +4,22 @@
 ### Added
 - ScaleOperations interface
 - Field extends ScaleOperations
+- Basic integration API
 
 ### Changed
 - Exponential operations merged with hyperbolic functions
 - Space is replaced by Group. Space is reserved for vector spaces.
 - VectorSpace is now a vector space
+- Buffer factories for primitives moved to MutableBuffer.Companion
+- NDStructure and NDAlgebra to StructureND and AlgebraND respectively
+- Real -> Double
 
 ### Deprecated
 
 ### Removed
 - Nearest in Domain. To be implemented in geometry package.
 - Number multiplication and division in main Algebra chain
+- `contentEquals` from Buffer. It moved to the companion.
 
 ### Fixed
 
@@ -72,6 +77,7 @@
 - `toGrid` method.
 - Public visibility of `BufferAccessor2D`
 - `Real` class
+- StructureND identity and equals
 
 ### Fixed
 - `symbol` method in `MstExtendedField` (https://github.com/mipt-npm/kmath/pull/140)

README.md

@@ -3,9 +3,7 @@
 
 ![Gradle build](https://github.com/mipt-npm/kmath/workflows/Gradle%20build/badge.svg)
 
-Bintray:        [ ![Download](https://api.bintray.com/packages/mipt-npm/kscience/kmath-core/images/download.svg) ](https://bintray.com/mipt-npm/kscience/kmath-core/_latestVersion)
+[![Maven Central](https://img.shields.io/maven-central/v/space.kscience/kmath-core.svg?label=Maven%20Central)](https://search.maven.org/search?q=g:%22space.kscience%22%20AND%20a:%22kmath-core%22)
-
-Bintray-dev:    [ ![Download](https://api.bintray.com/packages/mipt-npm/dev/kmath-core/images/download.svg) ](https://bintray.com/mipt-npm/dev/kmath-core/_latestVersion)
 
 # KMath
 
@@ -89,12 +87,12 @@ KMath is a modular library. Different modules provide different features with di
 > **Maturity**: PROTOTYPE
 >
 > **Features:**
-> - [expression-language](kmath-ast/src/jvmMain/kotlin/kscience/kmath/ast/parser.kt) : Expression language and its parser
+> - [expression-language](kmath-ast/src/jvmMain/kotlin/space/kscience/kmath/ast/parser.kt) : Expression language and its parser
-> - [mst](kmath-ast/src/commonMain/kotlin/kscience/kmath/ast/MST.kt) : MST (Mathematical Syntax Tree) as expression language's syntax intermediate representation
+> - [mst](kmath-ast/src/commonMain/kotlin/space/kscience/kmath/ast/MST.kt) : MST (Mathematical Syntax Tree) as expression language's syntax intermediate representation
-> - [mst-building](kmath-ast/src/commonMain/kotlin/kscience/kmath/ast/MstAlgebra.kt) : MST building algebraic structure
+> - [mst-building](kmath-ast/src/commonMain/kotlin/space/kscience/kmath/ast/MstAlgebra.kt) : MST building algebraic structure
-> - [mst-interpreter](kmath-ast/src/commonMain/kotlin/kscience/kmath/ast/MST.kt) : MST interpreter
+> - [mst-interpreter](kmath-ast/src/commonMain/kotlin/space/kscience/kmath/ast/MST.kt) : MST interpreter
-> - [mst-jvm-codegen](kmath-ast/src/jvmMain/kotlin/kscience/kmath/asm/asm.kt) : Dynamic MST to JVM bytecode compiler
+> - [mst-jvm-codegen](kmath-ast/src/jvmMain/kotlin/space/kscience/kmath/asm/asm.kt) : Dynamic MST to JVM bytecode compiler
-> - [mst-js-codegen](kmath-ast/src/jsMain/kotlin/kscience/kmath/estree/estree.kt) : Dynamic MST to JS compiler
+> - [mst-js-codegen](kmath-ast/src/jsMain/kotlin/space/kscience/kmath/estree/estree.kt) : Dynamic MST to JS compiler
 
 <hr/>
 
@@ -110,8 +108,8 @@ KMath is a modular library. Different modules provide different features with di
 > **Maturity**: PROTOTYPE
 >
 > **Features:**
-> - [complex](kmath-complex/src/commonMain/kotlin/kscience/kmath/complex/Complex.kt) : Complex Numbers
+> - [complex](kmath-complex/src/commonMain/kotlin/space/kscience/kmath/complex/Complex.kt) : Complex Numbers
-> - [quaternion](kmath-complex/src/commonMain/kotlin/kscience/kmath/complex/Quaternion.kt) : Quaternions
+> - [quaternion](kmath-complex/src/commonMain/kotlin/space/kscience/kmath/complex/Quaternion.kt) : Quaternions
 
 <hr/>
 
@@ -121,15 +119,15 @@ KMath is a modular library. Different modules provide different features with di
 > **Maturity**: DEVELOPMENT
 >
 > **Features:**
-> - [algebras](kmath-core/src/commonMain/kotlin/kscience/kmath/operations/Algebra.kt) : Algebraic structures like rings, spaces and fields.
+> - [algebras](kmath-core/src/commonMain/kotlin/space/kscience/kmath/operations/Algebra.kt) : Algebraic structures like rings, spaces and fields.
-> - [nd](kmath-core/src/commonMain/kotlin/kscience/kmath/structures/NDStructure.kt) : Many-dimensional structures and operations on them.
+> - [nd](kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/StructureND.kt) : Many-dimensional structures and operations on them.
-> - [linear](kmath-core/src/commonMain/kotlin/kscience/kmath/operations/Algebra.kt) : Basic linear algebra operations (sums, products, etc.), backed by the `Space` API. Advanced linear algebra operations like matrix inversion and LU decomposition.
+> - [linear](kmath-core/src/commonMain/kotlin/space/kscience/kmath/operations/Algebra.kt) : Basic linear algebra operations (sums, products, etc.), backed by the `Space` API. Advanced linear algebra operations like matrix inversion and LU decomposition.
-> - [buffers](kmath-core/src/commonMain/kotlin/kscience/kmath/structures/Buffers.kt) : One-dimensional structure
+> - [buffers](kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/Buffers.kt) : One-dimensional structure
-> - [expressions](kmath-core/src/commonMain/kotlin/kscience/kmath/expressions) : By writing a single mathematical expression once, users will be able to apply different types of 
+> - [expressions](kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions) : By writing a single mathematical expression once, users will be able to apply different types of 
 objects to the expression by providing a context. Expressions can be used for a wide variety of purposes from high 
 performance calculations to code generation.
-> - [domains](kmath-core/src/commonMain/kotlin/kscience/kmath/domains) : Domains
+> - [domains](kmath-core/src/commonMain/kotlin/space/kscience/kmath/domains) : Domains
-> - [autodif](kmath-core/src/commonMain/kotlin/kscience/kmath/expressions/SimpleAutoDiff.kt) : Automatic differentiation
+> - [autodif](kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/SimpleAutoDiff.kt) : Automatic differentiation
 
 <hr/>
 
@@ -159,9 +157,9 @@ One can still use generic algebras though.
 > **Maturity**: EXPERIMENTAL
 >
 > **Features:**
-> - [RealVector](kmath-for-real/src/commonMain/kotlin/kscience/kmath/real/RealVector.kt) : Numpy-like operations for Buffers/Points
+> - [DoubleVector](kmath-for-real/src/commonMain/kotlin/space/kscience/kmath/real/DoubleVector.kt) : Numpy-like operations for Buffers/Points
-> - [RealMatrix](kmath-for-real/src/commonMain/kotlin/kscience/kmath/real/RealMatrix.kt) : Numpy-like operations for 2d real structures
+> - [DoubleMatrix](kmath-for-real/src/commonMain/kotlin/space/kscience/kmath/real/DoubleMatrix.kt) : Numpy-like operations for 2d real structures
-> - [grids](kmath-for-real/src/commonMain/kotlin/kscience/kmath/structures/grids.kt) : Uniform grid generators
+> - [grids](kmath-for-real/src/commonMain/kotlin/space/kscience/kmath/structures/grids.kt) : Uniform grid generators
 
 <hr/>
 
@@ -171,10 +169,10 @@ One can still use generic algebras though.
 > **Maturity**: PROTOTYPE
 >
 > **Features:**
-> - [piecewise](kmath-functions/Piecewise functions.) : src/commonMain/kotlin/kscience/kmath/functions/Piecewise.kt
+> - [piecewise](kmath-functions/Piecewise functions.) : src/commonMain/kotlin/space/kscience/kmath/functions/Piecewise.kt
-> - [polynomials](kmath-functions/Polynomial functions.) : src/commonMain/kotlin/kscience/kmath/functions/Polynomial.kt
+> - [polynomials](kmath-functions/Polynomial functions.) : src/commonMain/kotlin/space/kscience/kmath/functions/Polynomial.kt
-> - [linear interpolation](kmath-functions/Linear XY interpolator.) : src/commonMain/kotlin/kscience/kmath/interpolation/LinearInterpolator.kt
+> - [linear interpolation](kmath-functions/Linear XY interpolator.) : src/commonMain/kotlin/space/kscience/kmath/interpolation/LinearInterpolator.kt
-> - [spline interpolation](kmath-functions/Cubic spline XY interpolator.) : src/commonMain/kotlin/kscience/kmath/interpolation/SplineInterpolator.kt
+> - [spline interpolation](kmath-functions/Cubic spline XY interpolator.) : src/commonMain/kotlin/space/kscience/kmath/interpolation/SplineInterpolator.kt
 
 <hr/>
 
@@ -208,9 +206,9 @@ One can still use generic algebras though.
 > **Maturity**: EXPERIMENTAL
 >
 > **Features:**
-> - [nd4jarraystructure](kmath-nd4j/src/commonMain/kotlin/kscience/kmath/operations/Algebra.kt) : NDStructure wrapper for INDArray
+> - [nd4jarraystructure](kmath-nd4j/#) : NDStructure wrapper for INDArray
-> - [nd4jarrayrings](kmath-nd4j/src/commonMain/kotlin/kscience/kmath/structures/NDStructure.kt) : Rings over Nd4jArrayStructure of Int and Long
+> - [nd4jarrayrings](kmath-nd4j/#) : Rings over Nd4jArrayStructure of Int and Long
-> - [nd4jarrayfields](kmath-nd4j/src/commonMain/kotlin/kscience/kmath/structures/Buffers.kt) : Fields over Nd4jArrayStructure of Float and Double
+> - [nd4jarrayfields](kmath-nd4j/#) : Fields over Nd4jArrayStructure of Float and Double
 
 <hr/>
 
@@ -256,8 +254,8 @@ repositories {
 }
 
 dependencies {
-    api("kscience.kmath:kmath-core:() -> kotlin.Any")
+    api("space.kscience:kmath-core:0.3.0-dev-3")
-    // api("kscience.kmath:kmath-core-jvm:() -> kotlin.Any") for jvm-specific version
+    // api("kscience.kmath:kmath-core-jvm:0.3.0-dev-3") for jvm-specific version
 }
 ```
 

build.gradle.kts

@@ -20,7 +20,7 @@ allprojects {
     }
 
     group = "space.kscience"
-    version = "0.3.0"
+    version = "0.3.0-dev-3"
 }
 
 subprojects {

docs/algebra.md

@@ -31,7 +31,7 @@ multiplication;
 - [Ring](http://mathworld.wolfram.com/Ring.html) adds multiplication and its neutral element (i.e. 1);
 - [Field](http://mathworld.wolfram.com/Field.html) adds division operation.
 
-A typical implementation of `Field<T>` is the `RealField` which works on doubles, and `VectorSpace` for `Space<T>`.
+A typical implementation of `Field<T>` is the `DoubleField` which works on doubles, and `VectorSpace` for `Space<T>`.
 
 In some cases algebra context can hold additional operations like `exp` or `sin`, and then it inherits appropriate
 interface. Also, contexts may have operations, which produce elements outside of the context. For example, `Matrix.dot` 

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+         d="m 3920,1480 h 860 v 980 h -860 z" /></clipPath>
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                 id="clipPath184"
                 clipPathUnits="userSpaceOnUse"><path
          id="path182"
-         d="m 4900,1480 h 620 v 980 h -620 z" /></clipPath><clipPath
+         d="m 4900,1480 h 620 v 980 h -620 z" /></clipPath>
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                 id="clipPath196"
                 clipPathUnits="userSpaceOnUse"><path
          id="path194"
-         d="m 5630,1480 h 860 v 980 h -860 z" /></clipPath><clipPath
+         d="m 5630,1480 h 860 v 980 h -860 z" /></clipPath>
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                 id="clipPath208"
                 clipPathUnits="userSpaceOnUse"><path
          id="path206"
-         d="m 2370,1470 h 1370 v 10 H 2370 Z" /></clipPath><clipPath
+         d="m 2370,1470 h 1370 v 10 H 2370 Z" /></clipPath>
+        <clipPath
                 id="clipPath220"
                 clipPathUnits="userSpaceOnUse"><path
          id="path218"
-         d="m 3920,1470 h 860 v 10 h -860 z" /></clipPath><clipPath
+         d="m 3920,1470 h 860 v 10 h -860 z" /></clipPath>
+        <clipPath
                 id="clipPath232"
                 clipPathUnits="userSpaceOnUse"><path
          id="path230"
-         d="m 4900,1470 h 620 v 10 h -620 z" /></clipPath><clipPath
+         d="m 4900,1470 h 620 v 10 h -620 z" /></clipPath>
+        <clipPath
                 id="clipPath244"
                 clipPathUnits="userSpaceOnUse"><path
          id="path242"
-         d="m 5630,1470 h 860 v 10 h -860 z" /></clipPath><clipPath
+         d="m 5630,1470 h 860 v 10 h -860 z" /></clipPath>
+        <clipPath
                 id="clipPath256"
                 clipPathUnits="userSpaceOnUse"><path
          id="path254"
-         d="m 3920,1450 h 860 v 20 h -860 z" /></clipPath><clipPath
+         d="m 3920,1450 h 860 v 20 h -860 z" /></clipPath>
+        <clipPath
                 id="clipPath268"
                 clipPathUnits="userSpaceOnUse"><path
          id="path266"
-         d="m 4900,1450 h 620 v 20 h -620 z" /></clipPath></defs><g
+         d="m 4900,1450 h 620 v 20 h -620 z" /></clipPath></defs>
+    <g
             transform="matrix(1.3333333,0,0,-1.3333333,0,529.33333)"
             id="g10"><g
        transform="scale(0.1)"
@@ -104,31 +125,31 @@
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-         d="m 3096.33,444.379 2388.2,3232.811 c 90.43,122.38 261.76,148.12 384.18,57.73 122.38,-90.39 148.13,-261.72 57.74,-384.1 L 3538.2,117.969 C 3447.77,-4.41016 3276.45,-30.1602 3154.06,60.2305 3031.64,150.66 3005.9,321.949 3096.33,444.379 Z" /><path
+            d="m 3096.33,444.379 2388.2,3232.811 c 90.43,122.38 261.76,148.12 384.18,57.73 122.38,-90.39 148.13,-261.72 57.74,-384.1 L 3538.2,117.969 C 3447.77,-4.41016 3276.45,-30.1602 3154.06,60.2305 3031.64,150.66 3005.9,321.949 3096.33,444.379 Z"/><path
             id="path18"
             style="fill:#000000;fill-opacity:1;fill-rule:nonzero;stroke:none"
-         d="m 734.691,901.211 h 5982.5 v 2109.69 h -5982.5 z" /><path
+            d="m 734.691,901.211 h 5982.5 v 2109.69 h -5982.5 z"/><path
             id="path20"
             style="fill:#ffffff;fill-opacity:1;fill-rule:nonzero;stroke:none"
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docs/nd-structure.md

@@ -10,11 +10,11 @@ structures. In `kmath` performance depends on which particular context was used
 Let us consider following contexts:
 ```kotlin
     // automatically build context most suited for given type.
-    val autoField = NDField.auto(RealField, dim, dim)
+    val autoField = NDField.auto(DoubleField, dim, dim)
     // specialized nd-field for Double. It works as generic Double field as well
     val specializedField = NDField.real(dim, dim)
     //A generic boxing field. It should be used for objects, not primitives.
-    val genericField = NDField.buffered(RealField, dim, dim)
+    val genericField = NDField.buffered(DoubleField, dim, dim)
 ```
 Now let us perform several tests and see which implementation is best suited for each case:
 

docs/templates/ARTIFACT-TEMPLATE.md

@@ -13,9 +13,6 @@
 >     maven { url 'https://repo.kotlin.link' }
 >     maven { url 'https://dl.bintray.com/hotkeytlt/maven' }
 >     maven { url "https://dl.bintray.com/kotlin/kotlin-eap" } // include for builds based on kotlin-eap
->//     Uncomment if repo.kotlin.link is unavailable 
->//     maven { url 'https://dl.bintray.com/mipt-npm/kscience' }
->//     maven { url 'https://dl.bintray.com/mipt-npm/dev' }
 > }
 > 
 > dependencies {
@@ -29,9 +26,6 @@
 >     maven("https://repo.kotlin.link")
 >     maven("https://dl.bintray.com/kotlin/kotlin-eap") // include for builds based on kotlin-eap
 >     maven("https://dl.bintray.com/hotkeytlt/maven") // required for a
->//     Uncomment if repo.kotlin.link is unavailable 
->//     maven("https://dl.bintray.com/mipt-npm/kscience")
->//     maven("https://dl.bintray.com/mipt-npm/dev")
 > }
 > 
 > dependencies {

docs/templates/README-TEMPLATE.md

@@ -3,9 +3,7 @@
 
 ![Gradle build](https://github.com/mipt-npm/kmath/workflows/Gradle%20build/badge.svg)
 
-Bintray:        [ ![Download](https://api.bintray.com/packages/mipt-npm/kscience/kmath-core/images/download.svg) ](https://bintray.com/mipt-npm/kscience/kmath-core/_latestVersion)
+[![Maven Central](https://img.shields.io/maven-central/v/space.kscience/kmath-core.svg?label=Maven%20Central)](https://search.maven.org/search?q=g:%22space.kscience%22%20AND%20a:%22kmath-core%22)
-
-Bintray-dev:    [ ![Download](https://api.bintray.com/packages/mipt-npm/dev/kmath-core/images/download.svg) ](https://bintray.com/mipt-npm/dev/kmath-core/_latestVersion)
 
 # KMath
 
@@ -106,7 +104,7 @@ repositories {
 }
 
 dependencies {
-    api("kscience.kmath:kmath-core:$version")
+    api("${group}:kmath-core:$version")
     // api("kscience.kmath:kmath-core-jvm:$version") for jvm-specific version
 }
 ```

examples/build.gradle.kts

@@ -92,6 +92,14 @@ benchmark {
         iterationTimeUnit = "ms" // time unity for iterationTime, default is seconds
         include("ExpressionsInterpretersBenchmark")
     }
+
+    configurations.register("matrixInverse") {
+        warmups = 1 // number of warmup iterations
+        iterations = 3 // number of iterations
+        iterationTime = 500 // time in seconds per iteration
+        iterationTimeUnit = "ms" // time unity for iterationTime, default is seconds
+        include("MatrixInverseBenchmark")
+    }
 }
 
 kotlin.sourceSets.all {
@@ -105,6 +113,6 @@ tasks.withType<KotlinCompile> {
     kotlinOptions.jvmTarget = "11"
 }
 
-readme{
+readme {
     maturity = ru.mipt.npm.gradle.Maturity.EXPERIMENTAL
 }

examples/src/benchmarks/kotlin/space/kscience/kmath/benchmarks/BufferBenchmark.kt

@@ -5,14 +5,14 @@ import kotlinx.benchmark.Scope
 import kotlinx.benchmark.State
 import space.kscience.kmath.complex.Complex
 import space.kscience.kmath.complex.complex
+import space.kscience.kmath.structures.DoubleBuffer
 import space.kscience.kmath.structures.MutableBuffer
-import space.kscience.kmath.structures.RealBuffer
 
 @State(Scope.Benchmark)
 internal class BufferBenchmark {
     @Benchmark
-    fun genericRealBufferReadWrite() {
+    fun genericDoubleBufferReadWrite() {
-        val buffer = RealBuffer(size) { it.toDouble() }
+        val buffer = DoubleBuffer(size) { it.toDouble() }
 
         (0 until size).forEach {
             buffer[it]

examples/src/benchmarks/kotlin/space/kscience/kmath/benchmarks/DotBenchmark.kt

@@ -4,14 +4,11 @@ import kotlinx.benchmark.Benchmark
 import kotlinx.benchmark.Blackhole
 import kotlinx.benchmark.Scope
 import kotlinx.benchmark.State
-import space.kscience.kmath.commons.linear.CMMatrixContext
+import space.kscience.kmath.commons.linear.CMLinearSpace
-import space.kscience.kmath.ejml.EjmlMatrixContext
+import space.kscience.kmath.ejml.EjmlLinearSpace
-import space.kscience.kmath.linear.BufferMatrixContext
+import space.kscience.kmath.linear.LinearSpace
-import space.kscience.kmath.linear.Matrix
+import space.kscience.kmath.linear.invoke
-import space.kscience.kmath.linear.RealMatrixContext
+import space.kscience.kmath.operations.DoubleField
-import space.kscience.kmath.operations.RealField
-import space.kscience.kmath.operations.invoke
-import space.kscience.kmath.structures.Buffer
 import kotlin.random.Random
 
 @State(Scope.Benchmark)
@@ -21,47 +18,47 @@ internal class DotBenchmark {
         const val dim = 1000
 
         //creating invertible matrix
-        val matrix1 = Matrix.real(dim, dim) { i, j -> if (i <= j) random.nextDouble() else 0.0 }
+        val matrix1 = LinearSpace.real.buildMatrix(dim, dim) { i, j -> if (i <= j) random.nextDouble() else 0.0 }
-        val matrix2 = Matrix.real(dim, dim) { i, j -> if (i <= j) random.nextDouble() else 0.0 }
+        val matrix2 = LinearSpace.real.buildMatrix(dim, dim) { i, j -> if (i <= j) random.nextDouble() else 0.0 }
 
-        val cmMatrix1 = CMMatrixContext { matrix1.toCM() }
+        val cmMatrix1 = CMLinearSpace { matrix1.toCM() }
-        val cmMatrix2 = CMMatrixContext { matrix2.toCM() }
+        val cmMatrix2 = CMLinearSpace { matrix2.toCM() }
 
-        val ejmlMatrix1 = EjmlMatrixContext { matrix1.toEjml() }
+        val ejmlMatrix1 = EjmlLinearSpace { matrix1.toEjml() }
-        val ejmlMatrix2 = EjmlMatrixContext { matrix2.toEjml() }
+        val ejmlMatrix2 = EjmlLinearSpace { matrix2.toEjml() }
     }
 
     @Benchmark
     fun cmDot(blackhole: Blackhole) {
-        CMMatrixContext {
+        CMLinearSpace.run {
             blackhole.consume(cmMatrix1 dot cmMatrix2)
         }
     }
 
     @Benchmark
     fun ejmlDot(blackhole: Blackhole) {
-        EjmlMatrixContext {
+        EjmlLinearSpace {
             blackhole.consume(ejmlMatrix1 dot ejmlMatrix2)
         }
     }
 
     @Benchmark
     fun ejmlDotWithConversion(blackhole: Blackhole) {
-        EjmlMatrixContext {
+        EjmlLinearSpace {
             blackhole.consume(matrix1 dot matrix2)
         }
     }
 
     @Benchmark
     fun bufferedDot(blackhole: Blackhole) {
-        BufferMatrixContext(RealField, Buffer.Companion::real).invoke {
+        LinearSpace.auto(DoubleField).invoke {
             blackhole.consume(matrix1 dot matrix2)
         }
     }
 
     @Benchmark
     fun realDot(blackhole: Blackhole) {
-        RealMatrixContext {
+        LinearSpace.real {
             blackhole.consume(matrix1 dot matrix2)
         }
     }

examples/src/benchmarks/kotlin/space/kscience/kmath/benchmarks/ExpressionsInterpretersBenchmark.kt

@@ -10,7 +10,7 @@ import space.kscience.kmath.expressions.Expression
 import space.kscience.kmath.expressions.expressionInField
 import space.kscience.kmath.expressions.invoke
 import space.kscience.kmath.expressions.symbol
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.bindSymbol
 import kotlin.random.Random
 
@@ -30,7 +30,7 @@ internal class ExpressionsInterpretersBenchmark {
     fun mstExpression(blackhole: Blackhole) {
         val expr = algebra.mstInField {
             val x = bindSymbol(x)
-            x * 2.0 + 2.0 / x - 16.0
+            x * 2.0 + number(2.0) / x - 16.0
         }
 
         invokeAndSum(expr, blackhole)
@@ -40,7 +40,7 @@ internal class ExpressionsInterpretersBenchmark {
     fun asmExpression(blackhole: Blackhole) {
         val expr = algebra.mstInField {
             val x = bindSymbol(x)
-            x * 2.0 + 2.0 / x - 16.0
+            x * 2.0 + number(2.0) / x - 16.0
         }.compile()
 
         invokeAndSum(expr, blackhole)
@@ -68,7 +68,7 @@ internal class ExpressionsInterpretersBenchmark {
     }
 
     private companion object {
-        private val algebra = RealField
+        private val algebra = DoubleField
         private val x by symbol
     }
 }

examples/src/benchmarks/kotlin/space/kscience/kmath/benchmarks/MatrixInverseBenchmark.kt

@@ -4,44 +4,44 @@ import kotlinx.benchmark.Benchmark
 import kotlinx.benchmark.Blackhole
 import kotlinx.benchmark.Scope
 import kotlinx.benchmark.State
-import space.kscience.kmath.commons.linear.CMMatrixContext
+import space.kscience.kmath.commons.linear.CMLinearSpace
-import space.kscience.kmath.commons.linear.CMMatrixContext.dot
 import space.kscience.kmath.commons.linear.inverse
-import space.kscience.kmath.ejml.EjmlMatrixContext
+import space.kscience.kmath.ejml.EjmlLinearSpace
 import space.kscience.kmath.ejml.inverse
-import space.kscience.kmath.linear.Matrix
+import space.kscience.kmath.linear.LinearSpace
-import space.kscience.kmath.linear.MatrixContext
 import space.kscience.kmath.linear.inverseWithLup
-import space.kscience.kmath.linear.real
+import space.kscience.kmath.linear.invoke
 import kotlin.random.Random
 
 @State(Scope.Benchmark)
-internal class LinearAlgebraBenchmark {
+internal class MatrixInverseBenchmark {
     companion object {
         val random = Random(1224)
         const val dim = 100
 
+        private val space = LinearSpace.real
+
         //creating invertible matrix
-        val u = Matrix.real(dim, dim) { i, j -> if (i <= j) random.nextDouble() else 0.0 }
+        val u = space.buildMatrix(dim, dim) { i, j -> if (i <= j) random.nextDouble() else 0.0 }
-        val l = Matrix.real(dim, dim) { i, j -> if (i >= j) random.nextDouble() else 0.0 }
+        val l = space.buildMatrix(dim, dim) { i, j -> if (i >= j) random.nextDouble() else 0.0 }
-        val matrix = l dot u
+        val matrix = space { l dot u }
     }
 
     @Benchmark
     fun kmathLupInversion(blackhole: Blackhole) {
-        blackhole.consume(MatrixContext.real.inverseWithLup(matrix))
+        blackhole.consume(LinearSpace.real.inverseWithLup(matrix))
     }
 
     @Benchmark
     fun cmLUPInversion(blackhole: Blackhole) {
-        with(CMMatrixContext) {
+        with(CMLinearSpace) {
             blackhole.consume(inverse(matrix))
         }
     }
 
     @Benchmark
     fun ejmlInverse(blackhole: Blackhole) {
-        with(EjmlMatrixContext) {
+        with(EjmlLinearSpace) {
             blackhole.consume(inverse(matrix))
         }
     }

examples/src/benchmarks/kotlin/space/kscience/kmath/benchmarks/NDFieldBenchmark.kt

@@ -5,7 +5,7 @@ import kotlinx.benchmark.Blackhole
 import kotlinx.benchmark.Scope
 import kotlinx.benchmark.State
 import space.kscience.kmath.nd.*
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.structures.Buffer
 
 @State(Scope.Benchmark)
@@ -13,7 +13,7 @@ internal class NDFieldBenchmark {
     @Benchmark
     fun autoFieldAdd(blackhole: Blackhole) {
         with(autoField) {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) { res += one }
             blackhole.consume(res)
         }
@@ -22,7 +22,7 @@ internal class NDFieldBenchmark {
     @Benchmark
     fun specializedFieldAdd(blackhole: Blackhole) {
         with(specializedField) {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) { res += 1.0 }
             blackhole.consume(res)
         }
@@ -32,7 +32,7 @@ internal class NDFieldBenchmark {
     @Benchmark
     fun boxingFieldAdd(blackhole: Blackhole) {
         with(genericField) {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) { res += 1.0 }
             blackhole.consume(res)
         }
@@ -41,8 +41,8 @@ internal class NDFieldBenchmark {
     private companion object {
         private const val dim = 1000
         private const val n = 100
-        private val autoField = NDAlgebra.auto(RealField, dim, dim)
+        private val autoField = AlgebraND.auto(DoubleField, dim, dim)
-        private val specializedField = NDAlgebra.real(dim, dim)
+        private val specializedField = AlgebraND.real(dim, dim)
-        private val genericField = NDAlgebra.field(RealField, Buffer.Companion::boxing, dim, dim)
+        private val genericField = AlgebraND.field(DoubleField, Buffer.Companion::boxing, dim, dim)
     }
 }

examples/src/benchmarks/kotlin/space/kscience/kmath/benchmarks/ViktorBenchmark.kt

@@ -5,11 +5,11 @@ import kotlinx.benchmark.Blackhole
 import kotlinx.benchmark.Scope
 import kotlinx.benchmark.State
 import org.jetbrains.bio.viktor.F64Array
-import space.kscience.kmath.nd.NDAlgebra
+import space.kscience.kmath.nd.AlgebraND
-import space.kscience.kmath.nd.NDStructure
+import space.kscience.kmath.nd.StructureND
 import space.kscience.kmath.nd.auto
 import space.kscience.kmath.nd.real
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.viktor.ViktorNDField
 
 @State(Scope.Benchmark)
@@ -17,7 +17,7 @@ internal class ViktorBenchmark {
     @Benchmark
     fun automaticFieldAddition(blackhole: Blackhole) {
         with(autoField) {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) { res += 1.0 }
             blackhole.consume(res)
         }
@@ -26,7 +26,7 @@ internal class ViktorBenchmark {
     @Benchmark
     fun realFieldAddition(blackhole: Blackhole) {
         with(realField) {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) { res += 1.0 }
             blackhole.consume(res)
         }
@@ -54,8 +54,8 @@ internal class ViktorBenchmark {
         private const val n = 100
 
         // automatically build context most suited for given type.
-        private val autoField = NDAlgebra.auto(RealField, dim, dim)
+        private val autoField = AlgebraND.auto(DoubleField, dim, dim)
-        private val realField = NDAlgebra.real(dim, dim)
+        private val realField = AlgebraND.real(dim, dim)
         private val viktorField = ViktorNDField(dim, dim)
     }
 }

examples/src/benchmarks/kotlin/space/kscience/kmath/benchmarks/ViktorLogBenchmark.kt

@@ -5,17 +5,17 @@ import kotlinx.benchmark.Blackhole
 import kotlinx.benchmark.Scope
 import kotlinx.benchmark.State
 import org.jetbrains.bio.viktor.F64Array
-import space.kscience.kmath.nd.NDAlgebra
+import space.kscience.kmath.nd.AlgebraND
 import space.kscience.kmath.nd.auto
 import space.kscience.kmath.nd.real
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
-import space.kscience.kmath.viktor.ViktorNDField
+import space.kscience.kmath.viktor.ViktorFieldND
 
 @State(Scope.Benchmark)
 internal class ViktorLogBenchmark {
     @Benchmark
     fun realFieldLog(blackhole: Blackhole) {
-        with(realField) {
+        with(realNdField) {
             val fortyTwo = produce { 42.0 }
             var res = one
             repeat(n) { res = ln(fortyTwo) }
@@ -46,8 +46,8 @@ internal class ViktorLogBenchmark {
         private const val n = 100
 
         // automatically build context most suited for given type.
-        private val autoField = NDAlgebra.auto(RealField, dim, dim)
+        private val autoField = AlgebraND.auto(DoubleField, dim, dim)
-        private val realField = NDAlgebra.real(dim, dim)
+        private val realNdField = AlgebraND.real(dim, dim)
-        private val viktorField = ViktorNDField(intArrayOf(dim, dim))
+        private val viktorField = ViktorFieldND(intArrayOf(dim, dim))
     }
 }

examples/src/main/kotlin/space/kscience/kmath/ast/expressions.kt

@@ -1,10 +1,10 @@
 package space.kscience.kmath.ast
 
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 
 fun main() {
-    val expr = RealField.mstInField {
+    val expr = DoubleField.mstInField {
         val x = bindSymbol("x")
         x * 2.0 + number(2.0) / x - 16.0
     }

examples/src/main/kotlin/space/kscience/kmath/ast/kotlingradSupport.kt

@@ -5,7 +5,7 @@ import space.kscience.kmath.expressions.derivative
 import space.kscience.kmath.expressions.invoke
 import space.kscience.kmath.expressions.symbol
 import space.kscience.kmath.kotlingrad.differentiable
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 
 /**
  * In this example, x^2-4*x-44 function is differentiated with Kotlin∇, and the autodiff result is compared with
@@ -14,11 +14,11 @@ import space.kscience.kmath.operations.RealField
 fun main() {
     val x by symbol
 
-    val actualDerivative = MstExpression(RealField, "x^2-4*x-44".parseMath())
+    val actualDerivative = MstExpression(DoubleField, "x^2-4*x-44".parseMath())
         .differentiable()
         .derivative(x)
         .compile()
 
-    val expectedDerivative = MstExpression(RealField, "2*x-4".parseMath()).compile()
+    val expectedDerivative = MstExpression(DoubleField, "2*x-4".parseMath()).compile()
     assert(actualDerivative("x" to 123.0) == expectedDerivative("x" to 123.0))
 }

examples/src/main/kotlin/space/kscience/kmath/commons/fit/fitWithAutoDiff.kt

@@ -8,7 +8,7 @@ import kscience.plotly.models.TraceValues
 import space.kscience.kmath.commons.optimization.chiSquared
 import space.kscience.kmath.commons.optimization.minimize
 import space.kscience.kmath.expressions.symbol
-import space.kscience.kmath.real.RealVector
+import space.kscience.kmath.real.DoubleVector
 import space.kscience.kmath.real.map
 import space.kscience.kmath.real.step
 import space.kscience.kmath.stat.*
@@ -26,7 +26,7 @@ private val c by symbol
 /**
  * Shortcut to use buffers in plotly
  */
-operator fun TraceValues.invoke(vector: RealVector) {
+operator fun TraceValues.invoke(vector: DoubleVector) {
     numbers = vector.asIterable()
 }
 
@@ -90,10 +90,10 @@ fun main() {
             }
         }
         br()
-        h3{
+        h3 {
             +"Fit result: $result"
         }
-        h3{
+        h3 {
             +"Chi2/dof = ${result.value / (x.size - 3)}"
         }
     }

examples/src/main/kotlin/space/kscience/kmath/linear/gradient.kt

@@ -0,0 +1,28 @@
+package space.kscience.kmath.linear
+
+import space.kscience.kmath.real.*
+import space.kscience.kmath.structures.DoubleBuffer
+
+fun main() {
+    val x0 = DoubleVector(0.0, 0.0, 0.0)
+    val sigma = DoubleVector(1.0, 1.0, 1.0)
+
+    val gaussian: (Point<Double>) -> Double = { x ->
+        require(x.size == x0.size)
+        kotlin.math.exp(-((x - x0) / sigma).square().sum())
+    }
+
+    fun ((Point<Double>) -> Double).grad(x: Point<Double>): Point<Double> {
+        require(x.size == x0.size)
+        return DoubleBuffer(x.size) { i ->
+            val h = sigma[i] / 5
+            val dVector = DoubleBuffer(x.size) { if (it == i) h else 0.0 }
+            val f1 = invoke(x + dVector / 2)
+            val f0 = invoke(x - dVector / 2)
+            (f1 - f0) / h
+        }
+    }
+
+    println(gaussian.grad(x0))
+
+}

examples/src/main/kotlin/space/kscience/kmath/operations/ComplexDemo.kt

@@ -2,17 +2,17 @@ package space.kscience.kmath.operations
 
 import space.kscience.kmath.complex.Complex
 import space.kscience.kmath.complex.complex
-import space.kscience.kmath.nd.NDAlgebra
+import space.kscience.kmath.nd.AlgebraND
 
 fun main() {
     // 2d element
-    val element = NDAlgebra.complex(2, 2).produce { (i, j) ->
+    val element = AlgebraND.complex(2, 2).produce { (i, j) ->
         Complex(i.toDouble() - j.toDouble(), i.toDouble() + j.toDouble())
     }
     println(element)
 
     // 1d element operation
-    val result = with(NDAlgebra.complex(8)) {
+    val result = with(AlgebraND.complex(8)) {
         val a = produce { (it) -> i * it - it.toDouble() }
         val b = 3
         val c = Complex(1.0, 1.0)

examples/src/main/kotlin/space/kscience/kmath/structures/ComplexND.kt

@@ -4,8 +4,8 @@ package space.kscience.kmath.structures
 
 import space.kscience.kmath.complex.*
 import space.kscience.kmath.linear.transpose
-import space.kscience.kmath.nd.NDAlgebra
+import space.kscience.kmath.nd.AlgebraND
-import space.kscience.kmath.nd.NDStructure
+import space.kscience.kmath.nd.StructureND
 import space.kscience.kmath.nd.as2D
 import space.kscience.kmath.nd.real
 import space.kscience.kmath.operations.invoke
@@ -15,12 +15,12 @@ fun main() {
     val dim = 1000
     val n = 1000
 
-    val realField = NDAlgebra.real(dim, dim)
+    val realField = AlgebraND.real(dim, dim)
-    val complexField: ComplexNDField = NDAlgebra.complex(dim, dim)
+    val complexField: ComplexFieldND = AlgebraND.complex(dim, dim)
 
     val realTime = measureTimeMillis {
         realField {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) {
                 res += 1.0
             }
@@ -31,7 +31,7 @@ fun main() {
 
     val complexTime = measureTimeMillis {
         complexField {
-            var res: NDStructure<Complex> = one
+            var res: StructureND<Complex> = one
             repeat(n) {
                 res += 1.0
             }

examples/src/main/kotlin/space/kscience/kmath/structures/NDField.kt

@@ -4,7 +4,7 @@ import kotlinx.coroutines.GlobalScope
 import org.nd4j.linalg.factory.Nd4j
 import space.kscience.kmath.nd.*
 import space.kscience.kmath.nd4j.Nd4jArrayField
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.invoke
 import space.kscience.kmath.viktor.ViktorNDField
 import kotlin.contracts.InvocationKind
@@ -24,56 +24,56 @@ fun main() {
     val n = 1000
 
     // automatically build context most suited for given type.
-    val autoField = NDAlgebra.auto(RealField, dim, dim)
+    val autoField = AlgebraND.auto(DoubleField, dim, dim)
     // specialized nd-field for Double. It works as generic Double field as well
-    val realField = NDAlgebra.real(dim, dim)
+    val realField = AlgebraND.real(dim, dim)
     //A generic boxing field. It should be used for objects, not primitives.
-    val boxingField = NDAlgebra.field(RealField, Buffer.Companion::boxing, dim, dim)
+    val boxingField = AlgebraND.field(DoubleField, Buffer.Companion::boxing, dim, dim)
     // Nd4j specialized field.
     val nd4jField = Nd4jArrayField.real(dim, dim)
     //viktor field
-    val viktorField = ViktorNDField(dim,dim)
+    val viktorField = ViktorNDField(dim, dim)
     //parallel processing based on Java Streams
-    val parallelField = NDAlgebra.realWithStream(dim,dim)
+    val parallelField = AlgebraND.realWithStream(dim, dim)
 
     measureAndPrint("Boxing addition") {
         boxingField {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) { res += 1.0 }
         }
     }
 
     measureAndPrint("Specialized addition") {
         realField {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) { res += 1.0 }
         }
     }
 
     measureAndPrint("Nd4j specialized addition") {
         nd4jField {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) { res += 1.0 }
         }
     }
 
     measureAndPrint("Viktor addition") {
         viktorField {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) { res += 1.0 }
         }
     }
 
     measureAndPrint("Parallel stream addition") {
         parallelField {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) { res += 1.0 }
         }
     }
 
     measureAndPrint("Automatic field addition") {
         autoField {
-            var res: NDStructure<Double> = one
+            var res: StructureND<Double> = one
             repeat(n) { res += 1.0 }
         }
     }

examples/src/main/kotlin/space/kscience/kmath/structures/ParallelRealNDField.kt

@@ -1,107 +0,0 @@
-package space.kscience.kmath.structures
-
-import space.kscience.kmath.misc.UnstableKMathAPI
-import space.kscience.kmath.nd.*
-import space.kscience.kmath.operations.ExtendedField
-import space.kscience.kmath.operations.NumbersAddOperations
-import space.kscience.kmath.operations.RealField
-import java.util.*
-import java.util.stream.IntStream
-
-/**
- * A demonstration implementation of NDField over Real using Java [DoubleStream] for parallel execution
- */
-@OptIn(UnstableKMathAPI::class)
-class StreamRealNDField(
-    override val shape: IntArray,
-) : NDField<Double, RealField>,
-    NumbersAddOperations<NDStructure<Double>>,
-    ExtendedField<NDStructure<Double>> {
-
-    private val strides = DefaultStrides(shape)
-    override val elementContext: RealField get() = RealField
-    override val zero: NDBuffer<Double> by lazy { produce { zero } }
-    override val one: NDBuffer<Double> by lazy { produce { one } }
-
-    override fun number(value: Number): NDBuffer<Double> {
-        val d = value.toDouble() // minimize conversions
-        return produce { d }
-    }
-
-    private val NDStructure<Double>.buffer: RealBuffer
-        get() = when {
-            !shape.contentEquals(this@StreamRealNDField.shape) -> throw ShapeMismatchException(
-                this@StreamRealNDField.shape,
-                shape
-            )
-            this is NDBuffer && this.strides == this@StreamRealNDField.strides -> this.buffer as RealBuffer
-            else -> RealBuffer(strides.linearSize) { offset -> get(strides.index(offset)) }
-        }
-
-
-    override fun produce(initializer: RealField.(IntArray) -> Double): NDBuffer<Double> {
-        val array = IntStream.range(0, strides.linearSize).parallel().mapToDouble { offset ->
-            val index = strides.index(offset)
-            RealField.initializer(index)
-        }.toArray()
-
-        return NDBuffer(strides, array.asBuffer())
-    }
-
-    override fun NDStructure<Double>.map(
-        transform: RealField.(Double) -> Double,
-    ): NDBuffer<Double> {
-        val array = Arrays.stream(buffer.array).parallel().map { RealField.transform(it) }.toArray()
-        return NDBuffer(strides, array.asBuffer())
-    }
-
-    override fun NDStructure<Double>.mapIndexed(
-        transform: RealField.(index: IntArray, Double) -> Double,
-    ): NDBuffer<Double> {
-        val array = IntStream.range(0, strides.linearSize).parallel().mapToDouble { offset ->
-            RealField.transform(
-                strides.index(offset),
-                buffer.array[offset]
-            )
-        }.toArray()
-
-        return NDBuffer(strides, array.asBuffer())
-    }
-
-    override fun combine(
-        a: NDStructure<Double>,
-        b: NDStructure<Double>,
-        transform: RealField.(Double, Double) -> Double,
-    ): NDBuffer<Double> {
-        val array = IntStream.range(0, strides.linearSize).parallel().mapToDouble { offset ->
-            RealField.transform(a.buffer.array[offset], b.buffer.array[offset])
-        }.toArray()
-        return NDBuffer(strides, array.asBuffer())
-    }
-
-    override fun NDStructure<Double>.unaryMinus(): NDStructure<Double> = map { -it }
-
-    override fun scale(a: NDStructure<Double>, value: Double): NDStructure<Double> = a.map { it * value }
-
-    override fun power(arg: NDStructure<Double>, pow: Number): NDBuffer<Double> = arg.map { power(it, pow) }
-
-    override fun exp(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { exp(it) }
-
-    override fun ln(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { ln(it) }
-
-    override fun sin(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { sin(it) }
-    override fun cos(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { cos(it) }
-    override fun tan(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { tan(it) }
-    override fun asin(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { asin(it) }
-    override fun acos(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { acos(it) }
-    override fun atan(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { atan(it) }
-
-    override fun sinh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { sinh(it) }
-    override fun cosh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { cosh(it) }
-    override fun tanh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { tanh(it) }
-    override fun asinh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { asinh(it) }
-    override fun acosh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { acosh(it) }
-    override fun atanh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { atanh(it) }
-}
-
-fun NDAlgebra.Companion.realWithStream(vararg shape: Int): StreamRealNDField = StreamRealNDField(shape)

examples/src/main/kotlin/space/kscience/kmath/structures/StreamDoubleFieldND.kt

@@ -0,0 +1,107 @@
+package space.kscience.kmath.structures
+
+import space.kscience.kmath.misc.UnstableKMathAPI
+import space.kscience.kmath.nd.*
+import space.kscience.kmath.operations.DoubleField
+import space.kscience.kmath.operations.ExtendedField
+import space.kscience.kmath.operations.NumbersAddOperations
+import java.util.*
+import java.util.stream.IntStream
+
+/**
+ * A demonstration implementation of NDField over Real using Java [DoubleStream] for parallel execution
+ */
+@OptIn(UnstableKMathAPI::class)
+class StreamDoubleFieldND(
+    override val shape: IntArray,
+) : FieldND<Double, DoubleField>,
+    NumbersAddOperations<StructureND<Double>>,
+    ExtendedField<StructureND<Double>> {
+
+    private val strides = DefaultStrides(shape)
+    override val elementContext: DoubleField get() = DoubleField
+    override val zero: BufferND<Double> by lazy { produce { zero } }
+    override val one: BufferND<Double> by lazy { produce { one } }
+
+    override fun number(value: Number): BufferND<Double> {
+        val d = value.toDouble() // minimize conversions
+        return produce { d }
+    }
+
+    private val StructureND<Double>.buffer: DoubleBuffer
+        get() = when {
+            !shape.contentEquals(this@StreamDoubleFieldND.shape) -> throw ShapeMismatchException(
+                this@StreamDoubleFieldND.shape,
+                shape
+            )
+            this is BufferND && this.strides == this@StreamDoubleFieldND.strides -> this.buffer as DoubleBuffer
+            else -> DoubleBuffer(strides.linearSize) { offset -> get(strides.index(offset)) }
+        }
+
+
+    override fun produce(initializer: DoubleField.(IntArray) -> Double): BufferND<Double> {
+        val array = IntStream.range(0, strides.linearSize).parallel().mapToDouble { offset ->
+            val index = strides.index(offset)
+            DoubleField.initializer(index)
+        }.toArray()
+
+        return BufferND(strides, array.asBuffer())
+    }
+
+    override fun StructureND<Double>.map(
+        transform: DoubleField.(Double) -> Double,
+    ): BufferND<Double> {
+        val array = Arrays.stream(buffer.array).parallel().map { DoubleField.transform(it) }.toArray()
+        return BufferND(strides, array.asBuffer())
+    }
+
+    override fun StructureND<Double>.mapIndexed(
+        transform: DoubleField.(index: IntArray, Double) -> Double,
+    ): BufferND<Double> {
+        val array = IntStream.range(0, strides.linearSize).parallel().mapToDouble { offset ->
+            DoubleField.transform(
+                strides.index(offset),
+                buffer.array[offset]
+            )
+        }.toArray()
+
+        return BufferND(strides, array.asBuffer())
+    }
+
+    override fun combine(
+        a: StructureND<Double>,
+        b: StructureND<Double>,
+        transform: DoubleField.(Double, Double) -> Double,
+    ): BufferND<Double> {
+        val array = IntStream.range(0, strides.linearSize).parallel().mapToDouble { offset ->
+            DoubleField.transform(a.buffer.array[offset], b.buffer.array[offset])
+        }.toArray()
+        return BufferND(strides, array.asBuffer())
+    }
+
+    override fun StructureND<Double>.unaryMinus(): StructureND<Double> = map { -it }
+
+    override fun scale(a: StructureND<Double>, value: Double): StructureND<Double> = a.map { it * value }
+
+    override fun power(arg: StructureND<Double>, pow: Number): BufferND<Double> = arg.map { power(it, pow) }
+
+    override fun exp(arg: StructureND<Double>): BufferND<Double> = arg.map { exp(it) }
+
+    override fun ln(arg: StructureND<Double>): BufferND<Double> = arg.map { ln(it) }
+
+    override fun sin(arg: StructureND<Double>): BufferND<Double> = arg.map { sin(it) }
+    override fun cos(arg: StructureND<Double>): BufferND<Double> = arg.map { cos(it) }
+    override fun tan(arg: StructureND<Double>): BufferND<Double> = arg.map { tan(it) }
+    override fun asin(arg: StructureND<Double>): BufferND<Double> = arg.map { asin(it) }
+    override fun acos(arg: StructureND<Double>): BufferND<Double> = arg.map { acos(it) }
+    override fun atan(arg: StructureND<Double>): BufferND<Double> = arg.map { atan(it) }
+
+    override fun sinh(arg: StructureND<Double>): BufferND<Double> = arg.map { sinh(it) }
+    override fun cosh(arg: StructureND<Double>): BufferND<Double> = arg.map { cosh(it) }
+    override fun tanh(arg: StructureND<Double>): BufferND<Double> = arg.map { tanh(it) }
+    override fun asinh(arg: StructureND<Double>): BufferND<Double> = arg.map { asinh(it) }
+    override fun acosh(arg: StructureND<Double>): BufferND<Double> = arg.map { acosh(it) }
+    override fun atanh(arg: StructureND<Double>): BufferND<Double> = arg.map { atanh(it) }
+}
+
+fun AlgebraND.Companion.realWithStream(vararg shape: Int): StreamDoubleFieldND = StreamDoubleFieldND(shape)

examples/src/main/kotlin/space/kscience/kmath/structures/StructureReadBenchmark.kt

@@ -1,16 +1,16 @@
 package space.kscience.kmath.structures
 
+import space.kscience.kmath.nd.BufferND
 import space.kscience.kmath.nd.DefaultStrides
-import space.kscience.kmath.nd.NDBuffer
 import kotlin.system.measureTimeMillis
 
 @Suppress("ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE")
 fun main() {
     val n = 6000
     val array = DoubleArray(n * n) { 1.0 }
-    val buffer = RealBuffer(array)
+    val buffer = DoubleBuffer(array)
     val strides = DefaultStrides(intArrayOf(n, n))
-    val structure = NDBuffer(strides, buffer)
+    val structure = BufferND(strides, buffer)
 
     measureTimeMillis {
         var res = 0.0

examples/src/main/kotlin/space/kscience/kmath/structures/StructureWriteBenchmark.kt

@@ -1,13 +1,13 @@
 package space.kscience.kmath.structures
 
-import space.kscience.kmath.nd.NDStructure
+import space.kscience.kmath.nd.StructureND
 import space.kscience.kmath.nd.mapToBuffer
 import kotlin.system.measureTimeMillis
 
 @Suppress("UNUSED_VARIABLE")
 fun main() {
     val n = 6000
-    val structure = NDStructure.build(intArrayOf(n, n), Buffer.Companion::auto) { 1.0 }
+    val structure = StructureND.buffered(intArrayOf(n, n), Buffer.Companion::auto) { 1.0 }
     structure.mapToBuffer { it + 1 } // warm-up
     val time1 = measureTimeMillis { val res = structure.mapToBuffer { it + 1 } }
     println("Structure mapping finished in $time1 millis")
@@ -20,10 +20,10 @@ fun main() {
 
     println("Array mapping finished in $time2 millis")
 
-    val buffer = RealBuffer(DoubleArray(n * n) { 1.0 })
+    val buffer = DoubleBuffer(DoubleArray(n * n) { 1.0 })
 
     val time3 = measureTimeMillis {
-        val target = RealBuffer(DoubleArray(n * n))
+        val target = DoubleBuffer(DoubleArray(n * n))
         val res = array.forEachIndexed { index, value ->
             target[index] = value + 1
         }

examples/src/main/kotlin/space/kscience/kmath/structures/typeSafeDimensions.kt

@@ -5,7 +5,7 @@ import space.kscience.kmath.dimensions.D3
 import space.kscience.kmath.dimensions.DMatrixContext
 import space.kscience.kmath.dimensions.Dimension
 
-private fun DMatrixContext<Double>.simple() {
+private fun DMatrixContext<Double, *>.simple() {
     val m1 = produce<D2, D3> { i, j -> (i + j).toDouble() }
     val m2 = produce<D3, D2> { i, j -> (i + j).toDouble() }
 
@@ -17,7 +17,7 @@ private object D5 : Dimension {
     override val dim: UInt = 5u
 }
 
-private fun DMatrixContext<Double>.custom() {
+private fun DMatrixContext<Double, *>.custom() {
     val m1 = produce<D2, D5> { i, j -> (i + j).toDouble() }
     val m2 = produce<D5, D2> { i, j -> (i - j).toDouble() }
     val m3 = produce<D2, D2> { i, j -> (i - j).toDouble() }

gradle.properties

@@ -1,10 +1,8 @@
 kotlin.code.style=official
+kotlin.mpp.enableGranularSourceSetsMetadata=true
 kotlin.mpp.stability.nowarn=true
+kotlin.native.enableDependencyPropagation=false
 kotlin.parallel.tasks.in.project=true
 org.gradle.configureondemand=true
-org.gradle.jvmargs=-XX:MaxMetaspaceSize=512m
+org.gradle.jvmargs=-XX:MaxMetaspaceSize=2G
 org.gradle.parallel=true
-
-kotlin.mpp.enableGranularSourceSetsMetadata=true
-kotlin.native.enableDependencyPropagation=false
-

kmath-ast/README.md

@@ -2,17 +2,17 @@
 
 This subproject implements the following features:
 
- - [expression-language](src/jvmMain/kotlin/kscience/kmath/ast/parser.kt) : Expression language and its parser
+ - [expression-language](src/jvmMain/kotlin/space/kscience/kmath/ast/parser.kt) : Expression language and its parser
- - [mst](src/commonMain/kotlin/kscience/kmath/ast/MST.kt) : MST (Mathematical Syntax Tree) as expression language's syntax intermediate representation
+ - [mst](src/commonMain/kotlin/space/kscience/kmath/ast/MST.kt) : MST (Mathematical Syntax Tree) as expression language's syntax intermediate representation
- - [mst-building](src/commonMain/kotlin/kscience/kmath/ast/MstAlgebra.kt) : MST building algebraic structure
+ - [mst-building](src/commonMain/kotlin/space/kscience/kmath/ast/MstAlgebra.kt) : MST building algebraic structure
- - [mst-interpreter](src/commonMain/kotlin/kscience/kmath/ast/MST.kt) : MST interpreter
+ - [mst-interpreter](src/commonMain/kotlin/space/kscience/kmath/ast/MST.kt) : MST interpreter
- - [mst-jvm-codegen](src/jvmMain/kotlin/kscience/kmath/asm/asm.kt) : Dynamic MST to JVM bytecode compiler
+ - [mst-jvm-codegen](src/jvmMain/kotlin/space/kscience/kmath/asm/asm.kt) : Dynamic MST to JVM bytecode compiler
- - [mst-js-codegen](src/jsMain/kotlin/kscience/kmath/estree/estree.kt) : Dynamic MST to JS compiler
+ - [mst-js-codegen](src/jsMain/kotlin/space/kscience/kmath/estree/estree.kt) : Dynamic MST to JS compiler
 
 
 > #### Artifact:
 >
-> This module artifact: `space.kscience:kmath-ast:0.2.0`.
+> This module artifact: `space.kscience:kmath-ast:0.3.0-dev-3`.
 >
 > Bintray release version:        [ ![Download](https://api.bintray.com/packages/mipt-npm/kscience/kmath-ast/images/download.svg) ](https://bintray.com/mipt-npm/kscience/kmath-ast/_latestVersion)
 >
@@ -25,13 +25,10 @@ This subproject implements the following features:
 >     maven { url 'https://repo.kotlin.link' }
 >     maven { url 'https://dl.bintray.com/hotkeytlt/maven' }
 >     maven { url "https://dl.bintray.com/kotlin/kotlin-eap" } // include for builds based on kotlin-eap
->//     Uncomment if repo.kotlin.link is unavailable 
->//     maven { url 'https://dl.bintray.com/mipt-npm/kscience' }
->//     maven { url 'https://dl.bintray.com/mipt-npm/dev' }
 > }
 > 
 > dependencies {
->     implementation 'space.kscience:kmath-ast:0.2.0'
+>     implementation 'space.kscience:kmath-ast:0.3.0-dev-3'
 > }
 > ```
 > **Gradle Kotlin DSL:**
@@ -41,13 +38,10 @@ This subproject implements the following features:
 >     maven("https://repo.kotlin.link")
 >     maven("https://dl.bintray.com/kotlin/kotlin-eap") // include for builds based on kotlin-eap
 >     maven("https://dl.bintray.com/hotkeytlt/maven") // required for a
->//     Uncomment if repo.kotlin.link is unavailable 
->//     maven("https://dl.bintray.com/mipt-npm/kscience")
->//     maven("https://dl.bintray.com/mipt-npm/dev")
 > }
 > 
 > dependencies {
->     implementation("space.kscience:kmath-ast:0.2.0")
+>     implementation("space.kscience:kmath-ast:0.3.0-dev-3")
 > }
 > ```
 
@@ -61,10 +55,10 @@ a special implementation of `Expression<T>` with implemented `invoke` function.
 For example, the following builder:
 
 ```kotlin
-RealField.mstInField { symbol("x") + 2 }.compile()
+DoubleField.mstInField { symbol("x") + 2 }.compile()
 ``` 
 
-… leads to generation of bytecode, which can be decompiled to the following Java class:
+… leads to generation of bytecode, which can be decompiled to the following Java class:
 
 ```java
 package space.kscience.kmath.asm.generated;
@@ -94,8 +88,8 @@ public final class AsmCompiledExpression_45045_0 implements Expression<Double> {
 This API extends MST and MstExpression, so you may optimize as both of them:
 
 ```kotlin
-RealField.mstInField { symbol("x") + 2 }.compile()
+DoubleField.mstInField { symbol("x") + 2 }.compile()
-RealField.expression("x+2".parseMath())
+DoubleField.expression("x+2".parseMath())
 ```
 
 #### Known issues
@@ -109,7 +103,7 @@ RealField.expression("x+2".parseMath())
 A similar feature is also available on JS.
 
 ```kotlin
-RealField.mstInField { symbol("x") + 2 }.compile()
+DoubleField.mstInField { symbol("x") + 2 }.compile()
 ``` 
 
 The code above returns expression implemented with such a JS function:

kmath-ast/build.gradle.kts

@@ -58,36 +58,36 @@ readme {
     feature(
         id = "expression-language",
         description = "Expression language and its parser",
-        ref = "src/jvmMain/kotlin/kscience/kmath/ast/parser.kt"
+        ref = "src/jvmMain/kotlin/space/kscience/kmath/ast/parser.kt"
     )
 
     feature(
         id = "mst",
         description = "MST (Mathematical Syntax Tree) as expression language's syntax intermediate representation",
-        ref = "src/commonMain/kotlin/kscience/kmath/ast/MST.kt"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/ast/MST.kt"
     )
 
     feature(
         id = "mst-building",
         description = "MST building algebraic structure",
-        ref = "src/commonMain/kotlin/kscience/kmath/ast/MstAlgebra.kt"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/ast/MstAlgebra.kt"
     )
 
     feature(
         id = "mst-interpreter",
         description = "MST interpreter",
-        ref = "src/commonMain/kotlin/kscience/kmath/ast/MST.kt"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/ast/MST.kt"
     )
 
     feature(
         id = "mst-jvm-codegen",
         description = "Dynamic MST to JVM bytecode compiler",
-        ref = "src/jvmMain/kotlin/kscience/kmath/asm/asm.kt"
+        ref = "src/jvmMain/kotlin/space/kscience/kmath/asm/asm.kt"
     )
 
     feature(
         id = "mst-js-codegen",
         description = "Dynamic MST to JS compiler",
-        ref = "src/jsMain/kotlin/kscience/kmath/estree/estree.kt"
+        ref = "src/jsMain/kotlin/space/kscience/kmath/estree/estree.kt"
     )
 }

kmath-ast/docs/README-TEMPLATE.md

@@ -16,7 +16,7 @@ a special implementation of `Expression<T>` with implemented `invoke` function.
 For example, the following builder:
 
 ```kotlin
-RealField.mstInField { symbol("x") + 2 }.compile()
+DoubleField.mstInField { symbol("x") + 2 }.compile()
 ``` 
 
 … leads to generation of bytecode, which can be decompiled to the following Java class:
@@ -49,8 +49,8 @@ public final class AsmCompiledExpression_45045_0 implements Expression<Double> {
 This API extends MST and MstExpression, so you may optimize as both of them:
 
 ```kotlin
-RealField.mstInField { symbol("x") + 2 }.compile()
+DoubleField.mstInField { symbol("x") + 2 }.compile()
-RealField.expression("x+2".parseMath())
+DoubleField.expression("x+2".parseMath())
 ```
 
 #### Known issues
@@ -64,7 +64,7 @@ RealField.expression("x+2".parseMath())
 A similar feature is also available on JS.
 
 ```kotlin
-RealField.mstInField { symbol("x") + 2 }.compile()
+DoubleField.mstInField { symbol("x") + 2 }.compile()
 ``` 
 
 The code above returns expression implemented with such a JS function:

kmath-ast/src/commonMain/kotlin/space/kscience/kmath/ast/MstAlgebra.kt

@@ -54,7 +54,7 @@ public object MstRing : Ring<MST>, NumbersAddOperations<MST>, ScaleOperations<MS
     public override val one: MST.Numeric = number(1.0)
 
     public override fun number(value: Number): MST.Numeric = MstGroup.number(value)
-    public override fun bindSymbol(value: String): MST.Symbolic = MstGroup.bindSymbol(value)
+    public override fun bindSymbol(value: String): MST.Symbolic = MstAlgebra.bindSymbol(value)
     public override fun add(a: MST, b: MST): MST.Binary = MstGroup.add(a, b)
 
     public override fun scale(a: MST, value: Double): MST.Binary =
@@ -83,7 +83,7 @@ public object MstField : Field<MST>, NumbersAddOperations<MST>, ScaleOperations<
 
     public override val one: MST.Numeric get() = MstRing.one
 
-    public override fun bindSymbol(value: String): MST.Symbolic = MstRing.bindSymbol(value)
+    public override fun bindSymbol(value: String): MST.Symbolic = MstAlgebra.bindSymbol(value)
     public override fun number(value: Number): MST.Numeric = MstRing.number(value)
     public override fun add(a: MST, b: MST): MST.Binary = MstRing.add(a, b)
 
@@ -112,7 +112,7 @@ public object MstExtendedField : ExtendedField<MST>, NumericAlgebra<MST> {
     public override val zero: MST.Numeric get() = MstField.zero
     public override val one: MST.Numeric get() = MstField.one
 
-    public override fun bindSymbol(value: String): MST.Symbolic = MstField.bindSymbol(value)
+    public override fun bindSymbol(value: String): MST.Symbolic = MstAlgebra.bindSymbol(value)
     public override fun number(value: Number): MST.Numeric = MstRing.number(value)
     public override fun sin(arg: MST): MST.Unary = unaryOperationFunction(TrigonometricOperations.SIN_OPERATION)(arg)
     public override fun cos(arg: MST): MST.Unary = unaryOperationFunction(TrigonometricOperations.COS_OPERATION)(arg)

kmath-ast/src/jsTest/kotlin/space/kscience/kmath/estree/TestESTreeConsistencyWithInterpreter.kt

@@ -5,7 +5,7 @@ import space.kscience.kmath.complex.ComplexField
 import space.kscience.kmath.complex.toComplex
 import space.kscience.kmath.expressions.invoke
 import space.kscience.kmath.operations.ByteRing
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
@@ -73,7 +73,7 @@ internal class TestESTreeConsistencyWithInterpreter {
 
     @Test
     fun realField() {
-        val res1 = RealField.mstInField {
+        val res1 = DoubleField.mstInField {
             +(3 - 2 + 2 * number(1) + 1.0) + binaryOperationFunction("+")(
                 (3.0 - (bindSymbol("x") + (scale(add(number(1.0), number(1.0)), 2.0) + 1.0))) * 3 - 1.0
                         + number(1),
@@ -81,7 +81,7 @@ internal class TestESTreeConsistencyWithInterpreter {
             ) + zero
         }("x" to 2.0)
 
-        val res2 = RealField.mstInField {
+        val res2 = DoubleField.mstInField {
             +(3 - 2 + 2 * number(1) + 1.0) + binaryOperationFunction("+")(
                 (3.0 - (bindSymbol("x") + (scale(add(number(1.0), number(1.0)), 2.0) + 1.0))) * 3 - 1.0
                         + number(1),

kmath-ast/src/jsTest/kotlin/space/kscience/kmath/estree/TestESTreeOperationsSupport.kt

@@ -4,7 +4,7 @@ import space.kscience.kmath.ast.mstInExtendedField
 import space.kscience.kmath.ast.mstInField
 import space.kscience.kmath.ast.mstInGroup
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 import kotlin.random.Random
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -12,27 +12,29 @@ import kotlin.test.assertEquals
 internal class TestESTreeOperationsSupport {
     @Test
     fun testUnaryOperationInvocation() {
-        val expression = RealField.mstInGroup { -bindSymbol("x") }.compile()
+        val expression = DoubleField.mstInGroup { -bindSymbol("x") }.compile()
         val res = expression("x" to 2.0)
         assertEquals(-2.0, res)
     }
 
     @Test
     fun testBinaryOperationInvocation() {
-        val expression = RealField.mstInGroup { -bindSymbol("x") + number(1.0) }.compile()
+        val expression = DoubleField.mstInGroup { -bindSymbol("x") + number(1.0) }.compile()
         val res = expression("x" to 2.0)
         assertEquals(-1.0, res)
     }
 
     @Test
     fun testConstProductInvocation() {
-        val res = RealField.mstInField { bindSymbol("x") * 2 }("x" to 2.0)
+        val res = DoubleField.mstInField { bindSymbol("x") * 2 }("x" to 2.0)
         assertEquals(4.0, res)
     }
 
     @Test
     fun testMultipleCalls() {
-        val e = RealField.mstInExtendedField { sin(bindSymbol("x")).pow(4) - 6 * bindSymbol("x") / tanh(bindSymbol("x")) }.compile()
+        val e =
+            DoubleField.mstInExtendedField { sin(bindSymbol("x")).pow(4) - 6 * bindSymbol("x") / tanh(bindSymbol("x")) }
+                .compile()
         val r = Random(0)
         var s = 0.0
         repeat(1000000) { s += e("x" to r.nextDouble()) }

kmath-ast/src/jsTest/kotlin/space/kscience/kmath/estree/TestESTreeSpecialization.kt

@@ -2,50 +2,50 @@ package space.kscience.kmath.estree
 
 import space.kscience.kmath.ast.mstInField
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
 internal class TestESTreeSpecialization {
     @Test
     fun testUnaryPlus() {
-        val expr = RealField.mstInField { unaryOperationFunction("+")(bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { unaryOperationFunction("+")(bindSymbol("x")) }.compile()
         assertEquals(2.0, expr("x" to 2.0))
     }
 
     @Test
     fun testUnaryMinus() {
-        val expr = RealField.mstInField { unaryOperationFunction("-")(bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { unaryOperationFunction("-")(bindSymbol("x")) }.compile()
         assertEquals(-2.0, expr("x" to 2.0))
     }
 
     @Test
     fun testAdd() {
-        val expr = RealField.mstInField { binaryOperationFunction("+")(bindSymbol("x"), bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { binaryOperationFunction("+")(bindSymbol("x"), bindSymbol("x")) }.compile()
         assertEquals(4.0, expr("x" to 2.0))
     }
 
     @Test
     fun testSine() {
-        val expr = RealField.mstInField { unaryOperationFunction("sin")(bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { unaryOperationFunction("sin")(bindSymbol("x")) }.compile()
         assertEquals(0.0, expr("x" to 0.0))
     }
 
     @Test
     fun testMinus() {
-        val expr = RealField.mstInField { binaryOperationFunction("-")(bindSymbol("x"), bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { binaryOperationFunction("-")(bindSymbol("x"), bindSymbol("x")) }.compile()
         assertEquals(0.0, expr("x" to 2.0))
     }
 
     @Test
     fun testDivide() {
-        val expr = RealField.mstInField { binaryOperationFunction("/")(bindSymbol("x"), bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { binaryOperationFunction("/")(bindSymbol("x"), bindSymbol("x")) }.compile()
         assertEquals(1.0, expr("x" to 2.0))
     }
 
     @Test
     fun testPower() {
-        val expr = RealField
+        val expr = DoubleField
             .mstInField { binaryOperationFunction("pow")(bindSymbol("x"), number(2)) }
             .compile()
 

kmath-ast/src/jvmMain/kotlin/space/kscience/kmath/asm/internal/codegenUtils.kt

@@ -86,7 +86,7 @@ internal inline fun ClassWriter.visitField(
     descriptor: String,
     signature: String?,
     value: Any?,
-    block: FieldVisitor.() -> Unit
+    block: FieldVisitor.() -> Unit,
 ): FieldVisitor {
     contract { callsInPlace(block, InvocationKind.EXACTLY_ONCE) }
     return visitField(access, name, descriptor, signature, value).apply(block)

kmath-ast/src/jvmTest/kotlin/space/kscience/kmath/asm/TestAsmConsistencyWithInterpreter.kt

@@ -5,7 +5,7 @@ import space.kscience.kmath.complex.ComplexField
 import space.kscience.kmath.complex.toComplex
 import space.kscience.kmath.expressions.invoke
 import space.kscience.kmath.operations.ByteRing
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
@@ -73,7 +73,7 @@ internal class TestAsmConsistencyWithInterpreter {
 
     @Test
     fun realField() {
-        val res1 = RealField.mstInField {
+        val res1 = DoubleField.mstInField {
             +(3 - 2 + 2 * number(1) + 1.0) + binaryOperationFunction("+")(
                 (3.0 - (bindSymbol("x") + (scale(add(number(1.0), number(1.0)), 2.0) + 1.0))) * 3 - 1.0
                         + number(1),
@@ -81,7 +81,7 @@ internal class TestAsmConsistencyWithInterpreter {
             ) + zero
         }("x" to 2.0)
 
-        val res2 = RealField.mstInField {
+        val res2 = DoubleField.mstInField {
             +(3 - 2 + 2 * number(1) + 1.0) + binaryOperationFunction("+")(
                 (3.0 - (bindSymbol("x") + (scale(add(number(1.0), number(1.0)), 2.0) + 1.0))) * 3 - 1.0
                         + number(1),

kmath-ast/src/jvmTest/kotlin/space/kscience/kmath/asm/TestAsmOperationsSupport.kt

@@ -4,7 +4,7 @@ import space.kscience.kmath.ast.mstInExtendedField
 import space.kscience.kmath.ast.mstInField
 import space.kscience.kmath.ast.mstInGroup
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 import kotlin.random.Random
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -12,27 +12,29 @@ import kotlin.test.assertEquals
 internal class TestAsmOperationsSupport {
     @Test
     fun testUnaryOperationInvocation() {
-        val expression = RealField.mstInGroup { -bindSymbol("x") }.compile()
+        val expression = DoubleField.mstInGroup { -bindSymbol("x") }.compile()
         val res = expression("x" to 2.0)
         assertEquals(-2.0, res)
     }
 
     @Test
     fun testBinaryOperationInvocation() {
-        val expression = RealField.mstInGroup { -bindSymbol("x") + number(1.0) }.compile()
+        val expression = DoubleField.mstInGroup { -bindSymbol("x") + number(1.0) }.compile()
         val res = expression("x" to 2.0)
         assertEquals(-1.0, res)
     }
 
     @Test
     fun testConstProductInvocation() {
-        val res = RealField.mstInField { bindSymbol("x") * 2 }("x" to 2.0)
+        val res = DoubleField.mstInField { bindSymbol("x") * 2 }("x" to 2.0)
         assertEquals(4.0, res)
     }
 
     @Test
     fun testMultipleCalls() {
-        val e = RealField.mstInExtendedField { sin(bindSymbol("x")).pow(4) - 6 * bindSymbol("x") / tanh(bindSymbol("x")) }.compile()
+        val e =
+            DoubleField.mstInExtendedField { sin(bindSymbol("x")).pow(4) - 6 * bindSymbol("x") / tanh(bindSymbol("x")) }
+                .compile()
         val r = Random(0)
         var s = 0.0
         repeat(1000000) { s += e("x" to r.nextDouble()) }

kmath-ast/src/jvmTest/kotlin/space/kscience/kmath/asm/TestAsmSpecialization.kt

@@ -2,50 +2,50 @@ package space.kscience.kmath.asm
 
 import space.kscience.kmath.ast.mstInField
 import space.kscience.kmath.expressions.invoke
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
 internal class TestAsmSpecialization {
     @Test
     fun testUnaryPlus() {
-        val expr = RealField.mstInField { unaryOperationFunction("+")(bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { unaryOperationFunction("+")(bindSymbol("x")) }.compile()
         assertEquals(2.0, expr("x" to 2.0))
     }
 
     @Test
     fun testUnaryMinus() {
-        val expr = RealField.mstInField { unaryOperationFunction("-")(bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { unaryOperationFunction("-")(bindSymbol("x")) }.compile()
         assertEquals(-2.0, expr("x" to 2.0))
     }
 
     @Test
     fun testAdd() {
-        val expr = RealField.mstInField { binaryOperationFunction("+")(bindSymbol("x"), bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { binaryOperationFunction("+")(bindSymbol("x"), bindSymbol("x")) }.compile()
         assertEquals(4.0, expr("x" to 2.0))
     }
 
     @Test
     fun testSine() {
-        val expr = RealField.mstInField { unaryOperationFunction("sin")(bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { unaryOperationFunction("sin")(bindSymbol("x")) }.compile()
         assertEquals(0.0, expr("x" to 0.0))
     }
 
     @Test
     fun testMinus() {
-        val expr = RealField.mstInField { binaryOperationFunction("-")(bindSymbol("x"), bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { binaryOperationFunction("-")(bindSymbol("x"), bindSymbol("x")) }.compile()
         assertEquals(0.0, expr("x" to 2.0))
     }
 
     @Test
     fun testDivide() {
-        val expr = RealField.mstInField { binaryOperationFunction("/")(bindSymbol("x"), bindSymbol("x")) }.compile()
+        val expr = DoubleField.mstInField { binaryOperationFunction("/")(bindSymbol("x"), bindSymbol("x")) }.compile()
         assertEquals(1.0, expr("x" to 2.0))
     }
 
     @Test
     fun testPower() {
-        val expr = RealField
+        val expr = DoubleField
             .mstInField { binaryOperationFunction("pow")(bindSymbol("x"), number(2)) }
             .compile()
 

kmath-ast/src/jvmTest/kotlin/space/kscience/kmath/ast/ParserPrecedenceTest.kt

@@ -1,12 +1,12 @@
 package space.kscience.kmath.ast
 
+import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.Field
-import space.kscience.kmath.operations.RealField
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
 internal class ParserPrecedenceTest {
-    private val f: Field<Double> = RealField
+    private val f: Field<Double> = DoubleField
 
     @Test
     fun test1(): Unit = assertEquals(6.0, f.evaluate("2*2+2".parseMath()))

kmath-ast/src/jvmTest/kotlin/space/kscience/kmath/ast/ParserTest.kt

@@ -4,7 +4,7 @@ import space.kscience.kmath.complex.Complex
 import space.kscience.kmath.complex.ComplexField
 import space.kscience.kmath.expressions.invoke
 import space.kscience.kmath.operations.Algebra
-import space.kscience.kmath.operations.RealField
+import space.kscience.kmath.operations.DoubleField
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
@@ -33,7 +33,7 @@ internal class ParserTest {
     @Test
     fun `evaluate MST with unary function`() {
         val mst = "sin(0)".parseMath()
-        val res = RealField.evaluate(mst)
+        val res = DoubleField.evaluate(mst)
         assertEquals(0.0, res)
     }
 

kmath-commons/build.gradle.kts

@@ -12,6 +12,6 @@ dependencies {
     api("org.apache.commons:commons-math3:3.6.1")
 }
 
-readme{
+readme {
     maturity = ru.mipt.npm.gradle.Maturity.EXPERIMENTAL
 }

kmath-commons/src/main/kotlin/space/kscience/kmath/commons/integration/CMIntegrator.kt

@@ -0,0 +1,92 @@
+package space.kscience.kmath.commons.integration
+
+import org.apache.commons.math3.analysis.integration.IterativeLegendreGaussIntegrator
+import org.apache.commons.math3.analysis.integration.SimpsonIntegrator
+import space.kscience.kmath.integration.*
+import space.kscience.kmath.misc.UnstableKMathAPI
+
+/**
+ * Integration wrapper for Common-maths UnivariateIntegrator
+ */
+public class CMIntegrator(
+    private val defaultMaxCalls: Int = 200,
+    public val integratorBuilder: (Integrand) -> org.apache.commons.math3.analysis.integration.UnivariateIntegrator,
+) : UnivariateIntegrator<Double> {
+
+    public class TargetRelativeAccuracy(public val value: Double) : IntegrandFeature
+    public class TargetAbsoluteAccuracy(public val value: Double) : IntegrandFeature
+
+    public class MinIterations(public val value: Int) : IntegrandFeature
+    public class MaxIterations(public val value: Int) : IntegrandFeature
+
+    override fun integrate(integrand: UnivariateIntegrand<Double>): UnivariateIntegrand<Double> {
+        val integrator = integratorBuilder(integrand)
+        val maxCalls = integrand.getFeature<IntegrandMaxCalls>()?.maxCalls ?: defaultMaxCalls
+        val remainingCalls = maxCalls - integrand.calls
+        val range = integrand.getFeature<IntegrationRange<Double>>()?.range
+            ?: error("Integration range is not provided")
+        val res = integrator.integrate(remainingCalls, integrand.function, range.start, range.endInclusive)
+
+        return integrand +
+                IntegrandValue(res) +
+                IntegrandAbsoluteAccuracy(integrator.absoluteAccuracy) +
+                IntegrandRelativeAccuracy(integrator.relativeAccuracy) +
+                IntegrandCalls(integrator.evaluations + integrand.calls)
+    }
+
+
+    public companion object {
+        /**
+         * Create a Simpson integrator based on [SimpsonIntegrator]
+         */
+        public fun simpson(defaultMaxCalls: Int = 200): CMIntegrator = CMIntegrator(defaultMaxCalls) { integrand ->
+            val absoluteAccuracy = integrand.getFeature<TargetAbsoluteAccuracy>()?.value
+                ?: SimpsonIntegrator.DEFAULT_ABSOLUTE_ACCURACY
+            val relativeAccuracy = integrand.getFeature<TargetRelativeAccuracy>()?.value
+                ?: SimpsonIntegrator.DEFAULT_ABSOLUTE_ACCURACY
+            val minIterations = integrand.getFeature<MinIterations>()?.value
+                ?: SimpsonIntegrator.DEFAULT_MIN_ITERATIONS_COUNT
+            val maxIterations = integrand.getFeature<MaxIterations>()?.value
+                ?: SimpsonIntegrator.SIMPSON_MAX_ITERATIONS_COUNT
+
+            SimpsonIntegrator(relativeAccuracy, absoluteAccuracy, minIterations, maxIterations)
+        }
+
+        /**
+         * Create a Gauss-Legandre integrator based on [IterativeLegendreGaussIntegrator]
+         */
+        public fun legandre(numPoints: Int, defaultMaxCalls: Int = numPoints * 5): CMIntegrator =
+            CMIntegrator(defaultMaxCalls) { integrand ->
+                val absoluteAccuracy = integrand.getFeature<TargetAbsoluteAccuracy>()?.value
+                    ?: IterativeLegendreGaussIntegrator.DEFAULT_ABSOLUTE_ACCURACY
+                val relativeAccuracy = integrand.getFeature<TargetRelativeAccuracy>()?.value
+                    ?: IterativeLegendreGaussIntegrator.DEFAULT_ABSOLUTE_ACCURACY
+                val minIterations = integrand.getFeature<MinIterations>()?.value
+                    ?: IterativeLegendreGaussIntegrator.DEFAULT_MIN_ITERATIONS_COUNT
+                val maxIterations = integrand.getFeature<MaxIterations>()?.value
+                    ?: IterativeLegendreGaussIntegrator.DEFAULT_MAX_ITERATIONS_COUNT
+
+                IterativeLegendreGaussIntegrator(
+                    numPoints,
+                    relativeAccuracy,
+                    absoluteAccuracy,
+                    minIterations,
+                    maxIterations
+                )
+            }
+    }
+}
+
+@UnstableKMathAPI
+public var MutableList<IntegrandFeature>.targetAbsoluteAccuracy: Double?
+    get() = filterIsInstance<CMIntegrator.TargetAbsoluteAccuracy>().lastOrNull()?.value
+    set(value) {
+        value?.let { add(CMIntegrator.TargetAbsoluteAccuracy(value)) }
+    }
+
+@UnstableKMathAPI
+public var MutableList<IntegrandFeature>.targetRelativeAccuracy: Double?
+    get() = filterIsInstance<CMIntegrator.TargetRelativeAccuracy>().lastOrNull()?.value
+    set(value) {
+        value?.let { add(CMIntegrator.TargetRelativeAccuracy(value)) }
+    }

kmath-commons/src/main/kotlin/space/kscience/kmath/commons/integration/GaussRuleIntegrator.kt

@@ -0,0 +1,94 @@
+/* 
+ * Copyright 2015 Alexander Nozik.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package space.kscience.kmath.commons.integration
+
+import org.apache.commons.math3.analysis.integration.gauss.GaussIntegrator
+import org.apache.commons.math3.analysis.integration.gauss.GaussIntegratorFactory
+import space.kscience.kmath.integration.*
+
+/**
+ * A simple one-pass integrator based on Gauss rule
+ */
+public class GaussRuleIntegrator(
+    private val numpoints: Int,
+    private var type: GaussRule = GaussRule.LEGANDRE,
+) : UnivariateIntegrator<Double> {
+
+    override fun integrate(integrand: UnivariateIntegrand<Double>): UnivariateIntegrand<Double> {
+        val range = integrand.getFeature<IntegrationRange<Double>>()?.range
+            ?: error("Integration range is not provided")
+        val integrator: GaussIntegrator = getIntegrator(range)
+        //TODO check performance
+        val res: Double = integrator.integrate(integrand.function)
+        return integrand + IntegrandValue(res) + IntegrandCalls(integrand.calls + numpoints)
+    }
+
+    private fun getIntegrator(range: ClosedRange<Double>): GaussIntegrator {
+        return when (type) {
+            GaussRule.LEGANDRE -> factory.legendre(
+                numpoints,
+                range.start,
+                range.endInclusive
+            )
+            GaussRule.LEGANDREHP -> factory.legendreHighPrecision(
+                numpoints,
+                range.start,
+                range.endInclusive
+            )
+            GaussRule.UNIFORM -> GaussIntegrator(
+                getUniformRule(
+                    range.start,
+                    range.endInclusive,
+                    numpoints
+                )
+            )
+        }
+    }
+
+    private fun getUniformRule(
+        min: Double,
+        max: Double,
+        numPoints: Int,
+    ): org.apache.commons.math3.util.Pair<DoubleArray, DoubleArray> {
+        assert(numPoints > 2)
+        val points = DoubleArray(numPoints)
+        val weights = DoubleArray(numPoints)
+        val step = (max - min) / (numPoints - 1)
+        points[0] = min
+        for (i in 1 until numPoints) {
+            points[i] = points[i - 1] + step
+            weights[i] = step
+        }
+        return org.apache.commons.math3.util.Pair<DoubleArray, DoubleArray>(points, weights)
+    }
+
+    public enum class GaussRule {
+        UNIFORM, LEGANDRE, LEGANDREHP
+    }
+
+    public companion object {
+        private val factory: GaussIntegratorFactory = GaussIntegratorFactory()
+
+        public fun integrate(
+            range: ClosedRange<Double>,
+            numPoints: Int = 100,
+            type: GaussRule = GaussRule.LEGANDRE,
+            function: (Double) -> Double,
+        ): Double = GaussRuleIntegrator(numPoints, type).integrate(
+            UnivariateIntegrand(function, IntegrationRange(range))
+        ).value!!
+    }
+}

kmath-commons/src/main/kotlin/space/kscience/kmath/commons/linear/CMMatrix.kt

@@ -3,7 +3,8 @@ package space.kscience.kmath.commons.linear
 import org.apache.commons.math3.linear.*
 import space.kscience.kmath.linear.*
 import space.kscience.kmath.misc.UnstableKMathAPI
-import space.kscience.kmath.structures.RealBuffer
+import space.kscience.kmath.operations.DoubleField
+import space.kscience.kmath.structures.DoubleBuffer
 import kotlin.reflect.KClass
 import kotlin.reflect.cast
 
@@ -11,8 +12,90 @@ public inline class CMMatrix(public val origin: RealMatrix) : Matrix<Double> {
     public override val rowNum: Int get() = origin.rowDimension
     public override val colNum: Int get() = origin.columnDimension
 
+    public override operator fun get(i: Int, j: Int): Double = origin.getEntry(i, j)
+}
+
+public inline class CMVector(public val origin: RealVector) : Point<Double> {
+    public override val size: Int get() = origin.dimension
+
+    public override operator fun get(index: Int): Double = origin.getEntry(index)
+
+    public override operator fun iterator(): Iterator<Double> = origin.toArray().iterator()
+}
+
+public fun RealVector.toPoint(): CMVector = CMVector(this)
+
+public object CMLinearSpace : LinearSpace<Double, DoubleField> {
+    override val elementAlgebra: DoubleField get() = DoubleField
+
+    public override fun buildMatrix(
+        rows: Int,
+        columns: Int,
+        initializer: DoubleField.(i: Int, j: Int) -> Double,
+    ): CMMatrix {
+        val array = Array(rows) { i -> DoubleArray(columns) { j -> DoubleField.initializer(i, j) } }
+        return CMMatrix(Array2DRowRealMatrix(array))
+    }
+
+    @OptIn(UnstableKMathAPI::class)
+    public fun Matrix<Double>.toCM(): CMMatrix = when (val matrix = origin) {
+        is CMMatrix -> matrix
+        else -> {
+            //TODO add feature analysis
+            val array = Array(rowNum) { i -> DoubleArray(colNum) { j -> get(i, j) } }
+            Array2DRowRealMatrix(array).wrap()
+        }
+    }
+
+    public fun Point<Double>.toCM(): CMVector = if (this is CMVector) this else {
+        val array = DoubleArray(size) { this[it] }
+        ArrayRealVector(array).wrap()
+    }
+
+    internal fun RealMatrix.wrap(): CMMatrix = CMMatrix(this)
+    internal fun RealVector.wrap(): CMVector = CMVector(this)
+
+    override fun buildVector(size: Int, initializer: DoubleField.(Int) -> Double): Point<Double> =
+        ArrayRealVector(DoubleArray(size) { DoubleField.initializer(it) }).wrap()
+
+    override fun Matrix<Double>.plus(other: Matrix<Double>): CMMatrix =
+        toCM().origin.add(other.toCM().origin).wrap()
+
+    override fun Point<Double>.plus(other: Point<Double>): CMVector =
+        toCM().origin.add(other.toCM().origin).wrap()
+
+    override fun Point<Double>.minus(other: Point<Double>): CMVector =
+        toCM().origin.subtract(other.toCM().origin).wrap()
+
+    public override fun Matrix<Double>.dot(other: Matrix<Double>): CMMatrix =
+        toCM().origin.multiply(other.toCM().origin).wrap()
+
+    public override fun Matrix<Double>.dot(vector: Point<Double>): CMVector =
+        toCM().origin.preMultiply(vector.toCM().origin).wrap()
+
+    public override operator fun Matrix<Double>.minus(other: Matrix<Double>): CMMatrix =
+        toCM().origin.subtract(other.toCM().origin).wrap()
+
+    public override operator fun Matrix<Double>.times(value: Double): CMMatrix =
+        toCM().origin.scalarMultiply(value).wrap()
+
+    override fun Double.times(m: Matrix<Double>): CMMatrix =
+        m * this
+
+    override fun Point<Double>.times(value: Double): CMVector =
+        toCM().origin.mapMultiply(value).wrap()
+
+    override fun Double.times(v: Point<Double>): CMVector =
+        v * this
+
     @UnstableKMathAPI
-    override fun <T : Any> getFeature(type: KClass<T>): T? = when (type) {
+    override fun <F : Any> getFeature(structure: Matrix<Double>, type: KClass<F>): F? {
+        //Return the feature if it is intrinsic to the structure
+        structure.getFeature(type)?.let { return it }
+
+        val origin = structure.toCM().origin
+
+        return when (type) {
             DiagonalFeature::class -> if (origin is DiagonalMatrix) DiagonalFeature else null
 
             DeterminantFeature::class, LupDecompositionFeature::class -> object :
@@ -43,79 +126,15 @@ public inline class CMMatrix(public val origin: RealMatrix) : Matrix<Double> {
                 override val u: Matrix<Double> by lazy { CMMatrix(sv.u) }
                 override val s: Matrix<Double> by lazy { CMMatrix(sv.s) }
                 override val v: Matrix<Double> by lazy { CMMatrix(sv.v) }
-            override val singularValues: Point<Double> by lazy { RealBuffer(sv.singularValues) }
+                override val singularValues: Point<Double> by lazy { DoubleBuffer(sv.singularValues) }
             }
-
             else -> null
         }?.let(type::cast)
-
-    public override operator fun get(i: Int, j: Int): Double = origin.getEntry(i, j)
-}
-
-
-public fun RealMatrix.asMatrix(): CMMatrix = CMMatrix(this)
-
-public class CMVector(public val origin: RealVector) : Point<Double> {
-    public override val size: Int get() = origin.dimension
-
-    public override operator fun get(index: Int): Double = origin.getEntry(index)
-
-    public override operator fun iterator(): Iterator<Double> = origin.toArray().iterator()
-}
-
-public fun Point<Double>.toCM(): CMVector = if (this is CMVector) this else {
-    val array = DoubleArray(size) { this[it] }
-    CMVector(ArrayRealVector(array))
-}
-
-public fun RealVector.toPoint(): CMVector = CMVector(this)
-
-public object CMMatrixContext : MatrixContext<Double, CMMatrix> {
-    public override fun produce(rows: Int, columns: Int, initializer: (i: Int, j: Int) -> Double): CMMatrix {
-        val array = Array(rows) { i -> DoubleArray(columns) { j -> initializer(i, j) } }
-        return CMMatrix(Array2DRowRealMatrix(array))
     }
-
-    @OptIn(UnstableKMathAPI::class)
-    public fun Matrix<Double>.toCM(): CMMatrix = when (val matrix = origin) {
-        is CMMatrix -> matrix
-        else -> {
-            //TODO add feature analysis
-            val array = Array(rowNum) { i -> DoubleArray(colNum) { j -> get(i, j) } }
-            CMMatrix(Array2DRowRealMatrix(array))
-        }
-    }
-
-    override fun scale(a: Matrix<Double>, value: Double): Matrix<Double> = a.toCM().times(value)
-
-
-    public override fun Matrix<Double>.dot(other: Matrix<Double>): CMMatrix =
-        CMMatrix(toCM().origin.multiply(other.toCM().origin))
-
-    public override fun Matrix<Double>.dot(vector: Point<Double>): CMVector =
-        CMVector(toCM().origin.preMultiply(vector.toCM().origin))
-
-    public override operator fun Matrix<Double>.unaryMinus(): CMMatrix =
-        produce(rowNum, colNum) { i, j -> -get(i, j) }
-
-    public override fun add(a: Matrix<Double>, b: Matrix<Double>): CMMatrix =
-        CMMatrix(a.toCM().origin.multiply(b.toCM().origin))
-
-    public override operator fun Matrix<Double>.minus(b: Matrix<Double>): CMMatrix =
-        CMMatrix(toCM().origin.subtract(b.toCM().origin))
-
-//    public override fun multiply(a: Matrix<Double>, k: Number): CMMatrix =
-//        CMMatrix(a.toCM().origin.scalarMultiply(k.toDouble()))
-
-    public override operator fun Matrix<Double>.times(value: Double): CMMatrix =
-        produce(rowNum, colNum) { i, j -> get(i, j) * value }
 }
 
-public operator fun CMMatrix.plus(other: CMMatrix): CMMatrix =
+public operator fun CMMatrix.plus(other: CMMatrix): CMMatrix = CMMatrix(origin.add(other.origin))
-    CMMatrix(origin.add(other.origin))
 
-public operator fun CMMatrix.minus(other: CMMatrix): CMMatrix =
+public operator fun CMMatrix.minus(other: CMMatrix): CMMatrix = CMMatrix(origin.subtract(other.origin))
-    CMMatrix(origin.subtract(other.origin))
 
-public infix fun CMMatrix.dot(other: CMMatrix): CMMatrix =
+public infix fun CMMatrix.dot(other: CMMatrix): CMMatrix = CMMatrix(origin.multiply(other.origin))
-    CMMatrix(origin.multiply(other.origin))

kmath-commons/src/main/kotlin/space/kscience/kmath/commons/linear/CMSolver.kt

@@ -12,9 +12,9 @@ public enum class CMDecomposition {
     CHOLESKY
 }
 
-public fun CMMatrixContext.solver(
+public fun CMLinearSpace.solver(
     a: Matrix<Double>,
-    decomposition: CMDecomposition = CMDecomposition.LUP
+    decomposition: CMDecomposition = CMDecomposition.LUP,
 ): DecompositionSolver = when (decomposition) {
     CMDecomposition.LUP -> LUDecomposition(a.toCM().origin).solver
     CMDecomposition.RRQR -> RRQRDecomposition(a.toCM().origin).solver
@@ -23,19 +23,19 @@ public fun CMMatrixContext.solver(
     CMDecomposition.CHOLESKY -> CholeskyDecomposition(a.toCM().origin).solver
 }
 
-public fun CMMatrixContext.solve(
+public fun CMLinearSpace.solve(
     a: Matrix<Double>,
     b: Matrix<Double>,
-    decomposition: CMDecomposition = CMDecomposition.LUP
+    decomposition: CMDecomposition = CMDecomposition.LUP,
-): CMMatrix = solver(a, decomposition).solve(b.toCM().origin).asMatrix()
+): CMMatrix = solver(a, decomposition).solve(b.toCM().origin).wrap()
 
-public fun CMMatrixContext.solve(
+public fun CMLinearSpace.solve(
     a: Matrix<Double>,
     b: Point<Double>,
-    decomposition: CMDecomposition = CMDecomposition.LUP
+    decomposition: CMDecomposition = CMDecomposition.LUP,
 ): CMVector = solver(a, decomposition).solve(b.toCM().origin).toPoint()
 
-public fun CMMatrixContext.inverse(
+public fun CMLinearSpace.inverse(
     a: Matrix<Double>,
-    decomposition: CMDecomposition = CMDecomposition.LUP
+    decomposition: CMDecomposition = CMDecomposition.LUP,
-): CMMatrix = solver(a, decomposition).inverse.asMatrix()
+): CMMatrix = solver(a, decomposition).inverse.wrap()

kmath-commons/src/main/kotlin/space/kscience/kmath/commons/optimization/CMOptimizationProblem.kt

@@ -19,7 +19,7 @@ import kotlin.reflect.KClass
 public operator fun PointValuePair.component1(): DoubleArray = point
 public operator fun PointValuePair.component2(): Double = value
 
-public class CMOptimizationProblem(override val symbols: List<Symbol>, ) :
+public class CMOptimizationProblem(override val symbols: List<Symbol>) :
     OptimizationProblem<Double>, SymbolIndexer, OptimizationFeature {
     private val optimizationData: HashMap<KClass<out OptimizationData>, OptimizationData> = HashMap()
     private var optimizatorBuilder: (() -> MultivariateOptimizer)? = null

kmath-commons/src/main/kotlin/space/kscience/kmath/commons/transform/Transformations.kt

@@ -10,6 +10,7 @@ import space.kscience.kmath.streaming.spread
 import space.kscience.kmath.structures.*
 
 
+
 /**
  * Streaming and buffer transformations
  */
@@ -17,7 +18,7 @@ public object Transformations {
     private fun Buffer<Complex>.toArray(): Array<org.apache.commons.math3.complex.Complex> =
         Array(size) { org.apache.commons.math3.complex.Complex(get(it).re, get(it).im) }
 
-    private fun Buffer<Double>.asArray() = if (this is RealBuffer) {
+    private fun Buffer<Double>.asArray() = if (this is DoubleBuffer) {
         array
     } else {
         DoubleArray(size) { i -> get(i) }
@@ -33,34 +34,34 @@ public object Transformations {
 
     public fun fourier(
         normalization: DftNormalization = DftNormalization.STANDARD,
-        direction: TransformType = TransformType.FORWARD
+        direction: TransformType = TransformType.FORWARD,
     ): SuspendBufferTransform<Complex, Complex> = {
         FastFourierTransformer(normalization).transform(it.toArray(), direction).asBuffer()
     }
 
     public fun realFourier(
         normalization: DftNormalization = DftNormalization.STANDARD,
-        direction: TransformType = TransformType.FORWARD
+        direction: TransformType = TransformType.FORWARD,
     ): SuspendBufferTransform<Double, Complex> = {
         FastFourierTransformer(normalization).transform(it.asArray(), direction).asBuffer()
     }
 
     public fun sine(
         normalization: DstNormalization = DstNormalization.STANDARD_DST_I,
-        direction: TransformType = TransformType.FORWARD
+        direction: TransformType = TransformType.FORWARD,
     ): SuspendBufferTransform<Double, Double> = {
         FastSineTransformer(normalization).transform(it.asArray(), direction).asBuffer()
     }
 
     public fun cosine(
         normalization: DctNormalization = DctNormalization.STANDARD_DCT_I,
-        direction: TransformType = TransformType.FORWARD
+        direction: TransformType = TransformType.FORWARD,
     ): SuspendBufferTransform<Double, Double> = {
         FastCosineTransformer(normalization).transform(it.asArray(), direction).asBuffer()
     }
 
     public fun hadamard(
-        direction: TransformType = TransformType.FORWARD
+        direction: TransformType = TransformType.FORWARD,
     ): SuspendBufferTransform<Double, Double> = {
         FastHadamardTransformer().transform(it.asArray(), direction).asBuffer()
     }
@@ -72,7 +73,7 @@ public object Transformations {
 @FlowPreview
 public fun Flow<Buffer<Complex>>.FFT(
     normalization: DftNormalization = DftNormalization.STANDARD,
-    direction: TransformType = TransformType.FORWARD
+    direction: TransformType = TransformType.FORWARD,
 ): Flow<Buffer<Complex>> {
     val transform = Transformations.fourier(normalization, direction)
     return map { transform(it) }
@@ -82,7 +83,7 @@ public fun Flow<Buffer<Complex>>.FFT(
 @JvmName("realFFT")
 public fun Flow<Buffer<Double>>.FFT(
     normalization: DftNormalization = DftNormalization.STANDARD,
-    direction: TransformType = TransformType.FORWARD
+    direction: TransformType = TransformType.FORWARD,
 ): Flow<Buffer<Complex>> {
     val transform = Transformations.realFourier(normalization, direction)
     return map(transform)
@@ -96,7 +97,7 @@ public fun Flow<Buffer<Double>>.FFT(
 public fun Flow<Double>.FFT(
     bufferSize: Int = Int.MAX_VALUE,
     normalization: DftNormalization = DftNormalization.STANDARD,
-    direction: TransformType = TransformType.FORWARD
+    direction: TransformType = TransformType.FORWARD,
 ): Flow<Complex> = chunked(bufferSize).FFT(normalization, direction).spread()
 
 /**

kmath-commons/src/test/kotlin/space/kscience/kmath/commons/expressions/DerivativeStructureExpressionTest.kt

@@ -27,10 +27,10 @@ internal class AutoDiffTest {
             val y = bindSymbol("y")
             val z = x * (-sin(x * y) + y) + 2.0
             println(z.derivative(x))
-            println(z.derivative(y,x))
+            println(z.derivative(y, x))
             assertEquals(z.derivative(x, y), z.derivative(y, x))
             //check that improper order cause failure
-            assertFails { z.derivative(x,x,y) }
+            assertFails { z.derivative(x, x, y) }
         }
     }
 

kmath-commons/src/test/kotlin/space/kscience/kmath/commons/integration/IntegrationTest.kt

@@ -0,0 +1,30 @@
+package space.kscience.kmath.commons.integration
+
+import org.junit.jupiter.api.Test
+import space.kscience.kmath.integration.integrate
+import space.kscience.kmath.misc.UnstableKMathAPI
+import space.kscience.kmath.operations.DoubleField.sin
+import kotlin.math.PI
+import kotlin.math.abs
+import kotlin.test.assertTrue
+
+@UnstableKMathAPI
+internal class IntegrationTest {
+    private val function: (Double) -> Double = { sin(it) }
+
+    @Test
+    fun simpson() {
+        val res = CMIntegrator.simpson().integrate(0.0..2 * PI, function)
+        assertTrue { abs(res) < 1e-3 }
+    }
+
+    @Test
+    fun customSimpson() {
+        val res = CMIntegrator.simpson().integrate(0.0..PI, function) {
+            targetRelativeAccuracy = 1e-4
+            targetAbsoluteAccuracy = 1e-4
+        }
+        assertTrue { abs(res - 2) < 1e-3 }
+        assertTrue { abs(res - 2) > 1e-12 }
+    }
+}

kmath-complex/README.md

@@ -2,13 +2,13 @@
 
 Complex and hypercomplex number systems in KMath:
 
- - [complex](src/commonMain/kotlin/kscience/kmath/complex/Complex.kt) : Complex Numbers
+ - [complex](src/commonMain/kotlin/space/kscience/kmath/complex/Complex.kt) : Complex Numbers
- - [quaternion](src/commonMain/kotlin/kscience/kmath/complex/Quaternion.kt) : Quaternions
+ - [quaternion](src/commonMain/kotlin/space/kscience/kmath/complex/Quaternion.kt) : Quaternions
 
 
 > #### Artifact:
 >
-> This module artifact: `space.kscience:kmath-complex:0.2.0`.
+> This module artifact: `space.kscience:kmath-complex:0.3.0-dev-3`.
 >
 > Bintray release version:        [ ![Download](https://api.bintray.com/packages/mipt-npm/kscience/kmath-complex/images/download.svg) ](https://bintray.com/mipt-npm/kscience/kmath-complex/_latestVersion)
 >
@@ -21,13 +21,10 @@ Complex and hypercomplex number systems in KMath:
 >     maven { url 'https://repo.kotlin.link' }
 >     maven { url 'https://dl.bintray.com/hotkeytlt/maven' }
 >     maven { url "https://dl.bintray.com/kotlin/kotlin-eap" } // include for builds based on kotlin-eap
->//     Uncomment if repo.kotlin.link is unavailable 
->//     maven { url 'https://dl.bintray.com/mipt-npm/kscience' }
->//     maven { url 'https://dl.bintray.com/mipt-npm/dev' }
 > }
 > 
 > dependencies {
->     implementation 'space.kscience:kmath-complex:0.2.0'
+>     implementation 'space.kscience:kmath-complex:0.3.0-dev-3'
 > }
 > ```
 > **Gradle Kotlin DSL:**
@@ -37,12 +34,9 @@ Complex and hypercomplex number systems in KMath:
 >     maven("https://repo.kotlin.link")
 >     maven("https://dl.bintray.com/kotlin/kotlin-eap") // include for builds based on kotlin-eap
 >     maven("https://dl.bintray.com/hotkeytlt/maven") // required for a
->//     Uncomment if repo.kotlin.link is unavailable 
->//     maven("https://dl.bintray.com/mipt-npm/kscience")
->//     maven("https://dl.bintray.com/mipt-npm/dev")
 > }
 > 
 > dependencies {
->     implementation("space.kscience:kmath-complex:0.2.0")
+>     implementation("space.kscience:kmath-complex:0.3.0-dev-3")
 > }
 > ```

kmath-complex/build.gradle.kts

@@ -25,12 +25,12 @@ readme {
     feature(
         id = "complex",
         description = "Complex Numbers",
-        ref = "src/commonMain/kotlin/kscience/kmath/complex/Complex.kt"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/complex/Complex.kt"
     )
 
     feature(
         id = "quaternion",
         description = "Quaternions",
-        ref = "src/commonMain/kotlin/kscience/kmath/complex/Quaternion.kt"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/complex/Quaternion.kt"
     )
 }

kmath-complex/src/commonMain/kotlin/space/kscience/kmath/complex/ComplexFieldND.kt

@@ -1,10 +1,10 @@
 package space.kscience.kmath.complex
 
 import space.kscience.kmath.misc.UnstableKMathAPI
-import space.kscience.kmath.nd.BufferedNDField
+import space.kscience.kmath.nd.AlgebraND
-import space.kscience.kmath.nd.NDAlgebra
+import space.kscience.kmath.nd.BufferND
-import space.kscience.kmath.nd.NDBuffer
+import space.kscience.kmath.nd.BufferedFieldND
-import space.kscience.kmath.nd.NDStructure
+import space.kscience.kmath.nd.StructureND
 import space.kscience.kmath.operations.ExtendedField
 import space.kscience.kmath.operations.NumbersAddOperations
 import space.kscience.kmath.structures.Buffer
@@ -16,16 +16,16 @@ import kotlin.contracts.contract
  * An optimized nd-field for complex numbers
  */
 @OptIn(UnstableKMathAPI::class)
-public class ComplexNDField(
+public class ComplexFieldND(
     shape: IntArray,
-) : BufferedNDField<Complex, ComplexField>(shape, ComplexField, Buffer.Companion::complex),
+) : BufferedFieldND<Complex, ComplexField>(shape, ComplexField, Buffer.Companion::complex),
-    NumbersAddOperations<NDStructure<Complex>>,
+    NumbersAddOperations<StructureND<Complex>>,
-    ExtendedField<NDStructure<Complex>> {
+    ExtendedField<StructureND<Complex>> {
 
-    override val zero: NDBuffer<Complex> by lazy { produce { zero } }
+    override val zero: BufferND<Complex> by lazy { produce { zero } }
-    override val one: NDBuffer<Complex> by lazy { produce { one } }
+    override val one: BufferND<Complex> by lazy { produce { one } }
 
-    override fun number(value: Number): NDBuffer<Complex> {
+    override fun number(value: Number): BufferND<Complex> {
         val d = value.toComplex() // minimize conversions
         return produce { d }
     }
@@ -34,15 +34,15 @@ public class ComplexNDField(
 //    @Suppress("OVERRIDE_BY_INLINE")
 //    override inline fun map(
 //        arg: AbstractNDBuffer<Double>,
-//        transform: RealField.(Double) -> Double,
+//        transform: DoubleField.(Double) -> Double,
 //    ): RealNDElement {
 //        check(arg)
-//        val array = RealBuffer(arg.strides.linearSize) { offset -> RealField.transform(arg.buffer[offset]) }
+//        val array = RealBuffer(arg.strides.linearSize) { offset -> DoubleField.transform(arg.buffer[offset]) }
 //        return BufferedNDFieldElement(this, array)
 //    }
 //
 //    @Suppress("OVERRIDE_BY_INLINE")
-//    override inline fun produce(initializer: RealField.(IntArray) -> Double): RealNDElement {
+//    override inline fun produce(initializer: DoubleField.(IntArray) -> Double): RealNDElement {
 //        val array = RealBuffer(strides.linearSize) { offset -> elementContext.initializer(strides.index(offset)) }
 //        return BufferedNDFieldElement(this, array)
 //    }
@@ -50,7 +50,7 @@ public class ComplexNDField(
 //    @Suppress("OVERRIDE_BY_INLINE")
 //    override inline fun mapIndexed(
 //        arg: AbstractNDBuffer<Double>,
-//        transform: RealField.(index: IntArray, Double) -> Double,
+//        transform: DoubleField.(index: IntArray, Double) -> Double,
 //    ): RealNDElement {
 //        check(arg)
 //        return BufferedNDFieldElement(
@@ -67,7 +67,7 @@ public class ComplexNDField(
 //    override inline fun combine(
 //        a: AbstractNDBuffer<Double>,
 //        b: AbstractNDBuffer<Double>,
-//        transform: RealField.(Double, Double) -> Double,
+//        transform: DoubleField.(Double, Double) -> Double,
 //    ): RealNDElement {
 //        check(a, b)
 //        val buffer = RealBuffer(strides.linearSize) { offset ->
@@ -76,44 +76,44 @@ public class ComplexNDField(
 //        return BufferedNDFieldElement(this, buffer)
 //    }
 
-    override fun power(arg: NDStructure<Complex>, pow: Number): NDBuffer<Complex> = arg.map { power(it, pow) }
+    override fun power(arg: StructureND<Complex>, pow: Number): BufferND<Complex> = arg.map { power(it, pow) }
 
-    override fun exp(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { exp(it) }
+    override fun exp(arg: StructureND<Complex>): BufferND<Complex> = arg.map { exp(it) }
 
-    override fun ln(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { ln(it) }
+    override fun ln(arg: StructureND<Complex>): BufferND<Complex> = arg.map { ln(it) }
 
-    override fun sin(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { sin(it) }
+    override fun sin(arg: StructureND<Complex>): BufferND<Complex> = arg.map { sin(it) }
-    override fun cos(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { cos(it) }
+    override fun cos(arg: StructureND<Complex>): BufferND<Complex> = arg.map { cos(it) }
-    override fun tan(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { tan(it) }
+    override fun tan(arg: StructureND<Complex>): BufferND<Complex> = arg.map { tan(it) }
-    override fun asin(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { asin(it) }
+    override fun asin(arg: StructureND<Complex>): BufferND<Complex> = arg.map { asin(it) }
-    override fun acos(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { acos(it) }
+    override fun acos(arg: StructureND<Complex>): BufferND<Complex> = arg.map { acos(it) }
-    override fun atan(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { atan(it) }
+    override fun atan(arg: StructureND<Complex>): BufferND<Complex> = arg.map { atan(it) }
 
-    override fun sinh(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { sinh(it) }
+    override fun sinh(arg: StructureND<Complex>): BufferND<Complex> = arg.map { sinh(it) }
-    override fun cosh(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { cosh(it) }
+    override fun cosh(arg: StructureND<Complex>): BufferND<Complex> = arg.map { cosh(it) }
-    override fun tanh(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { tanh(it) }
+    override fun tanh(arg: StructureND<Complex>): BufferND<Complex> = arg.map { tanh(it) }
-    override fun asinh(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { asinh(it) }
+    override fun asinh(arg: StructureND<Complex>): BufferND<Complex> = arg.map { asinh(it) }
-    override fun acosh(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { acosh(it) }
+    override fun acosh(arg: StructureND<Complex>): BufferND<Complex> = arg.map { acosh(it) }
-    override fun atanh(arg: NDStructure<Complex>): NDBuffer<Complex> = arg.map { atanh(it) }
+    override fun atanh(arg: StructureND<Complex>): BufferND<Complex> = arg.map { atanh(it) }
 }
 
 
 /**
  * Fast element production using function inlining
  */
-public inline fun BufferedNDField<Complex, ComplexField>.produceInline(initializer: ComplexField.(Int) -> Complex): NDBuffer<Complex> {
+public inline fun BufferedFieldND<Complex, ComplexField>.produceInline(initializer: ComplexField.(Int) -> Complex): BufferND<Complex> {
     contract { callsInPlace(initializer, InvocationKind.EXACTLY_ONCE) }
     val buffer = Buffer.complex(strides.linearSize) { offset -> ComplexField.initializer(offset) }
-    return NDBuffer(strides, buffer)
+    return BufferND(strides, buffer)
 }
 
 
-public fun NDAlgebra.Companion.complex(vararg shape: Int): ComplexNDField = ComplexNDField(shape)
+public fun AlgebraND.Companion.complex(vararg shape: Int): ComplexFieldND = ComplexFieldND(shape)
 
 /**
  * Produce a context for n-dimensional operations inside this real field
  */
-public inline fun <R> ComplexField.nd(vararg shape: Int, action: ComplexNDField.() -> R): R {
+public inline fun <R> ComplexField.nd(vararg shape: Int, action: ComplexFieldND.() -> R): R {
     contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
-    return ComplexNDField(shape).action()
+    return ComplexFieldND(shape).action()
 }

kmath-complex/src/commonMain/kotlin/space/kscience/kmath/complex/Quaternion.kt

@@ -172,7 +172,7 @@ public object QuaternionField : Field<Quaternion>, Norm<Quaternion, Quaternion>,
         else -> super<Field>.bindSymbol(value)
     }
 
-    override fun number(value: Number): Quaternion =value.toQuaternion()
+    override fun number(value: Number): Quaternion = value.toQuaternion()
 
     public override fun sinh(arg: Quaternion): Quaternion = (exp(arg) - exp(-arg)) / 2.0
     public override fun cosh(arg: Quaternion): Quaternion = (exp(arg) + exp(-arg)) / 2.0

kmath-core/README.md

@@ -0,0 +1,49 @@
+# The Core Module (`kmath-core`)
+
+The core features of KMath:
+
+ - [algebras](src/commonMain/kotlin/space/kscience/kmath/operations/Algebra.kt) : Algebraic structures like rings, spaces and fields.
+ - [nd](src/commonMain/kotlin/space/kscience/kmath/structures/StructureND.kt) : Many-dimensional structures and operations on them.
+ - [linear](src/commonMain/kotlin/space/kscience/kmath/operations/Algebra.kt) : Basic linear algebra operations (sums, products, etc.), backed by the `Space` API. Advanced linear algebra operations like matrix inversion and LU decomposition.
+ - [buffers](src/commonMain/kotlin/space/kscience/kmath/structures/Buffers.kt) : One-dimensional structure
+ - [expressions](src/commonMain/kotlin/space/kscience/kmath/expressions) : By writing a single mathematical expression once, users will be able to apply different types of 
+objects to the expression by providing a context. Expressions can be used for a wide variety of purposes from high 
+performance calculations to code generation.
+ - [domains](src/commonMain/kotlin/space/kscience/kmath/domains) : Domains
+ - [autodif](src/commonMain/kotlin/space/kscience/kmath/expressions/SimpleAutoDiff.kt) : Automatic differentiation
+
+
+> #### Artifact:
+>
+> This module artifact: `space.kscience:kmath-core:0.3.0-dev-3`.
+>
+> Bintray release version:        [ ![Download](https://api.bintray.com/packages/mipt-npm/kscience/kmath-core/images/download.svg) ](https://bintray.com/mipt-npm/kscience/kmath-core/_latestVersion)
+>
+> Bintray development version:    [ ![Download](https://api.bintray.com/packages/mipt-npm/dev/kmath-core/images/download.svg) ](https://bintray.com/mipt-npm/dev/kmath-core/_latestVersion)
+>
+> **Gradle:**
+>
+> ```gradle
+> repositories {
+>     maven { url 'https://repo.kotlin.link' }
+>     maven { url 'https://dl.bintray.com/hotkeytlt/maven' }
+>     maven { url "https://dl.bintray.com/kotlin/kotlin-eap" } // include for builds based on kotlin-eap
+> }
+> 
+> dependencies {
+>     implementation 'space.kscience:kmath-core:0.3.0-dev-3'
+> }
+> ```
+> **Gradle Kotlin DSL:**
+>
+> ```kotlin
+> repositories {
+>     maven("https://repo.kotlin.link")
+>     maven("https://dl.bintray.com/kotlin/kotlin-eap") // include for builds based on kotlin-eap
+>     maven("https://dl.bintray.com/hotkeytlt/maven") // required for a
+> }
+> 
+> dependencies {
+>     implementation("space.kscience:kmath-core:0.3.0-dev-3")
+> }
+> ```

kmath-core/build.gradle.kts

@@ -23,13 +23,13 @@ readme {
         description = """
             Algebraic structures like rings, spaces and fields.
         """.trimIndent(),
-        ref = "src/commonMain/kotlin/kscience/kmath/operations/Algebra.kt"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/operations/Algebra.kt"
     )
 
     feature(
         id = "nd",
         description = "Many-dimensional structures and operations on them.",
-        ref = "src/commonMain/kotlin/kscience/kmath/structures/NDStructure.kt"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/structures/StructureND.kt"
     )
 
     feature(
@@ -37,13 +37,13 @@ readme {
         description = """
             Basic linear algebra operations (sums, products, etc.), backed by the `Space` API. Advanced linear algebra operations like matrix inversion and LU decomposition.
         """.trimIndent(),
-        ref = "src/commonMain/kotlin/kscience/kmath/operations/Algebra.kt"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/operations/Algebra.kt"
     )
 
     feature(
         id = "buffers",
         description = "One-dimensional structure",
-        ref = "src/commonMain/kotlin/kscience/kmath/structures/Buffers.kt"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/structures/Buffers.kt"
     )
 
     feature(
@@ -53,18 +53,18 @@ readme {
             objects to the expression by providing a context. Expressions can be used for a wide variety of purposes from high 
             performance calculations to code generation.
         """.trimIndent(),
-        ref = "src/commonMain/kotlin/kscience/kmath/expressions"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/expressions"
     )
 
     feature(
         id = "domains",
         description = "Domains",
-        ref = "src/commonMain/kotlin/kscience/kmath/domains"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/domains"
     )
 
     feature(
         id = "autodif",
         description = "Automatic differentiation",
-        ref = "src/commonMain/kotlin/kscience/kmath/expressions/SimpleAutoDiff.kt"
+        ref = "src/commonMain/kotlin/space/kscience/kmath/expressions/SimpleAutoDiff.kt"
     )
 }

kmath-core/src/commonMain/kotlin/space/kscience/kmath/domains/DoubleDomain.kt

@@ -23,7 +23,7 @@ import space.kscience.kmath.misc.UnstableKMathAPI
  * @author Alexander Nozik
  */
 @UnstableKMathAPI
-public interface RealDomain : Domain<Double> {
+public interface DoubleDomain : Domain<Double> {
 
     /**
      * Global lower edge

kmath-core/src/commonMain/kotlin/space/kscience/kmath/domains/HyperSquareDomain.kt

@@ -27,7 +27,7 @@ import space.kscience.kmath.structures.indices
  * @author Alexander Nozik
  */
 @UnstableKMathAPI
-public class HyperSquareDomain(private val lower: Buffer<Double>, private val upper: Buffer<Double>) : RealDomain {
+public class HyperSquareDomain(private val lower: Buffer<Double>, private val upper: Buffer<Double>) : DoubleDomain {
     public override val dimension: Int get() = lower.size
 
     public override operator fun contains(point: Point<Double>): Boolean = point.indices.all { i ->

kmath-core/src/commonMain/kotlin/space/kscience/kmath/domains/UnconstrainedDomain.kt

@@ -19,7 +19,7 @@ import space.kscience.kmath.linear.Point
 import space.kscience.kmath.misc.UnstableKMathAPI
 
 @UnstableKMathAPI
-public class UnconstrainedDomain(public override val dimension: Int) : RealDomain {
+public class UnconstrainedDomain(public override val dimension: Int) : DoubleDomain {
     public override operator fun contains(point: Point<Double>): Boolean = true
 
     public override fun getLowerBound(num: Int): Double = Double.NEGATIVE_INFINITY

kmath-core/src/commonMain/kotlin/space/kscience/kmath/domains/UnivariateDomain.kt

@@ -4,7 +4,7 @@ import space.kscience.kmath.linear.Point
 import space.kscience.kmath.misc.UnstableKMathAPI
 
 @UnstableKMathAPI
-public inline class UnivariateDomain(public val range: ClosedFloatingPointRange<Double>) : RealDomain {
+public inline class UnivariateDomain(public val range: ClosedFloatingPointRange<Double>) : DoubleDomain {
     public override val dimension: Int get() = 1
 
     public operator fun contains(d: Double): Boolean = range.contains(d)

kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/DifferentiableExpression.kt

@@ -28,7 +28,7 @@ public fun <T, R : Expression<T>> DifferentiableExpression<T, R>.derivative(name
 /**
  * A [DifferentiableExpression] that defines only first derivatives
  */
-public abstract class FirstDerivativeExpression<T, R : Expression<T>> : DifferentiableExpression<T,R> {
+public abstract class FirstDerivativeExpression<T, R : Expression<T>> : DifferentiableExpression<T, R> {
     /**
      * Returns first derivative of this expression by given [symbol].
      */

kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/FunctionalExpressionAlgebra.kt

@@ -98,7 +98,7 @@ public open class FunctionalExpressionRing<T, A : Ring<T>>(
         super<FunctionalExpressionGroup>.binaryOperationFunction(operation)
 }
 
-public open class FunctionalExpressionField<T, A:  Field<T>>(
+public open class FunctionalExpressionField<T, A : Field<T>>(
     algebra: A,
 ) : FunctionalExpressionRing<T, A>(algebra), Field<Expression<T>>,
     ScaleOperations<Expression<T>> {

kmath-core/src/commonMain/kotlin/space/kscience/kmath/expressions/SimpleAutoDiff.kt

@@ -198,7 +198,7 @@ public open class SimpleAutoDiffField<T : Any, F : Field<T>>(
  * Example:
  * ```
  * val x by symbol // define variable(s) and their values
- * val y = RealField.withAutoDiff() { sqr(x) + 5 * x + 3 } // write formulate in deriv context
+ * val y = DoubleField.withAutoDiff() { sqr(x) + 5 * x + 3 } // write formulate in deriv context
  * assertEquals(17.0, y.x) // the value of result (y)
  * assertEquals(9.0, x.d)  // dy/dx
  * ```

kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/BufferMatrix.kt

@@ -1,144 +0,0 @@
-package space.kscience.kmath.linear
-
-import space.kscience.kmath.nd.NDStructure
-import space.kscience.kmath.nd.Structure2D
-import space.kscience.kmath.operations.Ring
-import space.kscience.kmath.operations.ScaleOperations
-import space.kscience.kmath.operations.invoke
-import space.kscience.kmath.structures.Buffer
-import space.kscience.kmath.structures.BufferFactory
-import space.kscience.kmath.structures.asSequence
-
-/**
- * Alias for [Structure2D] with more familiar name.
- *
- * @param T the type of items.
- */
-public typealias Matrix<T> = Structure2D<T>
-
-/**
- * Basic implementation of Matrix space based on [NDStructure]
- */
-public class BufferMatrixContext<T : Any, A>(
-    public override val elementContext: A,
-    private val bufferFactory: BufferFactory<T>,
-) : GenericMatrixContext<T, A, BufferMatrix<T>> where A : Ring<T>, A : ScaleOperations<T> {
-
-    public override fun produce(rows: Int, columns: Int, initializer: (i: Int, j: Int) -> T): BufferMatrix<T> {
-        val buffer = bufferFactory(rows * columns) { offset -> initializer(offset / columns, offset % columns) }
-        return BufferMatrix(rows, columns, buffer)
-    }
-
-    override fun scale(a: Matrix<T>, value: Double): Matrix<T> = elementContext {
-        produce(a.rowNum, a.colNum) { i, j ->
-            a[i, j] * value
-        }
-    }
-
-    public override fun point(size: Int, initializer: (Int) -> T): Point<T> = bufferFactory(size, initializer)
-
-    private fun Matrix<T>.toBufferMatrix(): BufferMatrix<T> = if (this is BufferMatrix) this else {
-        produce(rowNum, colNum) { i, j -> get(i, j) }
-    }
-
-    public fun one(rows: Int, columns: Int): Matrix<Double> = VirtualMatrix(rows, columns) { i, j ->
-        if (i == j) 1.0 else 0.0
-    } + DiagonalFeature
-
-    public override infix fun Matrix<T>.dot(other: Matrix<T>): BufferMatrix<T> {
-        require(colNum == other.rowNum) { "Matrix dot operation dimension mismatch: ($rowNum, $colNum) x (${other.rowNum}, ${other.colNum})" }
-        val bufferMatrix = toBufferMatrix()
-        val otherBufferMatrix = other.toBufferMatrix()
-        return elementContext {
-            produce(rowNum, other.colNum) { i, j ->
-                var res = one
-                for (l in 0 until colNum) {
-                    res += bufferMatrix[i, l] * otherBufferMatrix[l, j]
-                }
-                res
-            }
-        }
-    }
-
-    public override infix fun Matrix<T>.dot(vector: Point<T>): Point<T> {
-        require(colNum == vector.size) { "Matrix dot vector operation dimension mismatch: ($rowNum, $colNum) x (${vector.size})" }
-        val bufferMatrix = toBufferMatrix()
-        return elementContext {
-            bufferFactory(rowNum) { i ->
-                var res = one
-                for (j in 0 until colNum) {
-                    res += bufferMatrix[i, j] * vector[j]
-                }
-                res
-            }
-        }
-    }
-
-    override fun add(a: Matrix<T>, b: Matrix<T>): BufferMatrix<T> {
-        require(a.rowNum == b.rowNum) { "Row number mismatch in matrix addition. Left side: ${a.rowNum}, right side: ${b.rowNum}" }
-        require(a.colNum == b.colNum) { "Column number mismatch in matrix addition. Left side: ${a.colNum}, right side: ${b.colNum}" }
-        val aBufferMatrix = a.toBufferMatrix()
-        val bBufferMatrix = b.toBufferMatrix()
-        return elementContext {
-            produce(a.rowNum, a.colNum) { i, j ->
-                aBufferMatrix[i, j] + bBufferMatrix[i, j]
-            }
-        }
-    }
-
-//    override fun multiply(a: Matrix<T>, k: Number): BufferMatrix<T> {
-//        val aBufferMatrix = a.toBufferMatrix()
-//        return elementContext {
-//            produce(a.rowNum, a.colNum) { i, j -> aBufferMatrix[i, j] * k.toDouble() }
-//        }
-//    }
-
-    public companion object
-}
-
-public class BufferMatrix<T : Any>(
-    public override val rowNum: Int,
-    public override val colNum: Int,
-    public val buffer: Buffer<T>,
-) : Matrix<T> {
-
-    init {
-        require(buffer.size == rowNum * colNum) { "Dimension mismatch for matrix structure" }
-    }
-
-    override val shape: IntArray get() = intArrayOf(rowNum, colNum)
-
-    public override operator fun get(index: IntArray): T = get(index[0], index[1])
-    public override operator fun get(i: Int, j: Int): T = buffer[i * colNum + j]
-
-    public override fun elements(): Sequence<Pair<IntArray, T>> = sequence {
-        for (i in 0 until rowNum) for (j in 0 until colNum) yield(intArrayOf(i, j) to get(i, j))
-    }
-
-    public override fun equals(other: Any?): Boolean {
-        if (this === other) return true
-
-        return when (other) {
-            is NDStructure<*> -> NDStructure.contentEquals(this, other)
-            else -> false
-        }
-    }
-
-    override fun hashCode(): Int {
-        var result = rowNum
-        result = 31 * result + colNum
-        result = 31 * result + buffer.hashCode()
-        return result
-    }
-
-    public override fun toString(): String {
-        return if (rowNum <= 5 && colNum <= 5)
-            "Matrix(rowsNum = $rowNum, colNum = $colNum)\n" +
-                    rows.asSequence().joinToString(prefix = "(", postfix = ")", separator = "\n ") { buffer ->
-                        buffer.asSequence().joinToString(separator = "\t") { it.toString() }
-                    }
-        else "Matrix(rowsNum = $rowNum, colNum = $colNum)"
-    }
-
-
-}

kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/BufferedLinearSpace.kt

@@ -0,0 +1,83 @@
+package space.kscience.kmath.linear
+
+import space.kscience.kmath.nd.*
+import space.kscience.kmath.operations.Ring
+import space.kscience.kmath.operations.invoke
+import space.kscience.kmath.structures.Buffer
+import space.kscience.kmath.structures.BufferFactory
+import space.kscience.kmath.structures.VirtualBuffer
+import space.kscience.kmath.structures.indices
+
+
+public class BufferedLinearSpace<T : Any, A : Ring<T>>(
+    override val elementAlgebra: A,
+    private val bufferFactory: BufferFactory<T>,
+) : LinearSpace<T, A> {
+
+    private fun ndRing(
+        rows: Int,
+        cols: Int,
+    ): BufferedRingND<T, A> = AlgebraND.ring(elementAlgebra, bufferFactory, rows, cols)
+
+    override fun buildMatrix(rows: Int, columns: Int, initializer: A.(i: Int, j: Int) -> T): Matrix<T> =
+        ndRing(rows, columns).produce { (i, j) -> elementAlgebra.initializer(i, j) }.as2D()
+
+    override fun buildVector(size: Int, initializer: A.(Int) -> T): Point<T> =
+        bufferFactory(size) { elementAlgebra.initializer(it) }
+
+    override fun Matrix<T>.unaryMinus(): Matrix<T> = ndRing(rowNum, colNum).run {
+        unwrap().map { -it }.as2D()
+    }
+
+    override fun Matrix<T>.plus(other: Matrix<T>): Matrix<T> = ndRing(rowNum, colNum).run {
+        require(shape.contentEquals(other.shape)) { "Shape mismatch on Matrix::plus. Expected $shape but found ${other.shape}" }
+        unwrap().plus(other.unwrap()).as2D()
+    }
+
+    override fun Matrix<T>.minus(other: Matrix<T>): Matrix<T> = ndRing(rowNum, colNum).run {
+        require(shape.contentEquals(other.shape)) { "Shape mismatch on Matrix::minus. Expected $shape but found ${other.shape}" }
+        unwrap().minus(other.unwrap()).as2D()
+    }
+
+    private fun Buffer<T>.linearize() = if (this is VirtualBuffer) {
+        buildVector(size) { get(it) }
+    } else {
+        this
+    }
+
+    override fun Matrix<T>.dot(other: Matrix<T>): Matrix<T> {
+        require(colNum == other.rowNum) { "Matrix dot operation dimension mismatch: ($rowNum, $colNum) x (${other.rowNum}, ${other.colNum})" }
+        return elementAlgebra {
+            val rows = this@dot.rows.map { it.linearize() }
+            val columns = other.columns.map { it.linearize() }
+            buildMatrix(rowNum, other.colNum) { i, j ->
+                val r = rows[i]
+                val c = columns[j]
+                var res = zero
+                for (l in r.indices) {
+                    res += r[l] * c[l]
+                }
+                res
+            }
+        }
+    }
+
+    override fun Matrix<T>.dot(vector: Point<T>): Point<T> {
+        require(colNum == vector.size) { "Matrix dot vector operation dimension mismatch: ($rowNum, $colNum) x (${vector.size})" }
+        return elementAlgebra {
+            val rows = this@dot.rows.map { it.linearize() }
+            buildVector(rowNum) { i ->
+                val r = rows[i]
+                var res = zero
+                for (j in r.indices) {
+                    res += r[j] * vector[j]
+                }
+                res
+            }
+        }
+    }
+
+    override fun Matrix<T>.times(value: T): Matrix<T> = ndRing(rowNum, colNum).run {
+        unwrap().map { it * value }.as2D()
+    }
+}

kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/LinearSolver.kt

@@ -1,25 +1,33 @@
 package space.kscience.kmath.linear
 
-import space.kscience.kmath.structures.Buffer
+import space.kscience.kmath.nd.as1D
-import space.kscience.kmath.structures.VirtualBuffer
-
-public typealias Point<T> = Buffer<T>
 
 /**
  * A group of methods to resolve equation A dot X = B, where A and B are matrices or vectors
  */
 public interface LinearSolver<T : Any> {
+    /**
+     * Solve a dot x = b matrix equation and return x
+     */
     public fun solve(a: Matrix<T>, b: Matrix<T>): Matrix<T>
-    public fun solve(a: Matrix<T>, b: Point<T>): Point<T> = solve(a, b.asMatrix()).asPoint()
+
-    public fun inverse(a: Matrix<T>): Matrix<T>
+    /**
+     * Solve a dot x = b vector equation and return b
+     */
+    public fun solve(a: Matrix<T>, b: Point<T>): Point<T> = solve(a, b.asMatrix()).asVector()
+
+    /**
+     * Get inverse of a matrix
+     */
+    public fun inverse(matrix: Matrix<T>): Matrix<T>
 }
 
 /**
  * Convert matrix to vector if it is possible
  */
-public fun <T : Any> Matrix<T>.asPoint(): Point<T> =
+public fun <T : Any> Matrix<T>.asVector(): Point<T> =
     if (this.colNum == 1)
-        VirtualBuffer(rowNum) { get(it, 0) }
+        as1D()
     else
         error("Can't convert matrix with more than one column to vector")
 

kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/LinearSpace.kt

@@ -0,0 +1,202 @@
+package space.kscience.kmath.linear
+
+import space.kscience.kmath.misc.UnstableKMathAPI
+import space.kscience.kmath.nd.*
+import space.kscience.kmath.operations.*
+import space.kscience.kmath.structures.Buffer
+import space.kscience.kmath.structures.BufferFactory
+import space.kscience.kmath.structures.DoubleBuffer
+import kotlin.reflect.KClass
+
+/**
+ * Alias for [Structure2D] with more familiar name.
+ *
+ * @param T the type of items.
+ */
+public typealias Matrix<T> = Structure2D<T>
+
+/**
+ * Alias or using [Buffer] as a point/vector in a many-dimensional space.
+ */
+public typealias Point<T> = Buffer<T>
+
+/**
+ * Basic operations on matrices and vectors. Operates on [Matrix].
+ *
+ * @param T the type of items in the matrices.
+ * @param M the type of operated matrices.
+ */
+public interface LinearSpace<T : Any, out A : Ring<T>> {
+    public val elementAlgebra: A
+
+    /**
+     * Produces a matrix with this context and given dimensions.
+     */
+    public fun buildMatrix(rows: Int, columns: Int, initializer: A.(i: Int, j: Int) -> T): Matrix<T>
+
+    /**
+     * Produces a point compatible with matrix space (and possibly optimized for it).
+     */
+    public fun buildVector(size: Int, initializer: A.(Int) -> T): Point<T>
+
+    public operator fun Matrix<T>.unaryMinus(): Matrix<T> = buildMatrix(rowNum, colNum) { i, j ->
+        -get(i, j)
+    }
+
+    public operator fun Point<T>.unaryMinus(): Point<T> = buildVector(size) {
+        -get(it)
+    }
+
+    /**
+     * Matrix sum
+     */
+    public operator fun Matrix<T>.plus(other: Matrix<T>): Matrix<T> = buildMatrix(rowNum, colNum) { i, j ->
+        get(i, j) + other[i, j]
+    }
+
+
+    /**
+     * Vector sum
+     */
+    public operator fun Point<T>.plus(other: Point<T>): Point<T> = buildVector(size) {
+        get(it) + other[it]
+    }
+
+    /**
+     * Matrix subtraction
+     */
+    public operator fun Matrix<T>.minus(other: Matrix<T>): Matrix<T> = buildMatrix(rowNum, colNum) { i, j ->
+        get(i, j) - other[i, j]
+    }
+
+    /**
+     * Vector subtraction
+     */
+    public operator fun Point<T>.minus(other: Point<T>): Point<T> = buildVector(size) {
+        get(it) - other[it]
+    }
+
+
+    /**
+     * Computes the dot product of this matrix and another one.
+     *
+     * @receiver the multiplicand.
+     * @param other the multiplier.
+     * @return the dot product.
+     */
+    public infix fun Matrix<T>.dot(other: Matrix<T>): Matrix<T> {
+        require(colNum == other.rowNum) { "Matrix dot operation dimension mismatch: ($rowNum, $colNum) x (${other.rowNum}, ${other.colNum})" }
+        return elementAlgebra {
+            buildMatrix(rowNum, other.colNum) { i, j ->
+                var res = zero
+                for (l in 0 until colNum) {
+                    res += this@dot[i, l] * other[l, j]
+                }
+                res
+            }
+        }
+    }
+
+    /**
+     * Computes the dot product of this matrix and a vector.
+     *
+     * @receiver the multiplicand.
+     * @param vector the multiplier.
+     * @return the dot product.
+     */
+    public infix fun Matrix<T>.dot(vector: Point<T>): Point<T> {
+        require(colNum == vector.size) { "Matrix dot vector operation dimension mismatch: ($rowNum, $colNum) x (${vector.size})" }
+        return elementAlgebra {
+            buildVector(rowNum) { i ->
+                var res = one
+                for (j in 0 until colNum) {
+                    res += this@dot[i, j] * vector[j]
+                }
+                res
+            }
+        }
+    }
+
+    /**
+     * Multiplies a matrix by its element.
+     *
+     * @receiver the multiplicand.
+     * @param value the multiplier.
+     * @receiver the product.
+     */
+    public operator fun Matrix<T>.times(value: T): Matrix<T> =
+        buildMatrix(rowNum, colNum) { i, j -> get(i, j) * value }
+
+    /**
+     * Multiplies an element by a matrix of it.
+     *
+     * @receiver the multiplicand.
+     * @param m the multiplier.
+     * @receiver the product.
+     */
+    public operator fun T.times(m: Matrix<T>): Matrix<T> = m * this
+
+    /**
+     * Multiplies a vector by its element.
+     *
+     * @receiver the multiplicand.
+     * @param value the multiplier.
+     * @receiver the product.
+     */
+    public operator fun Point<T>.times(value: T): Point<T> =
+        buildVector(size) { i -> get(i) * value }
+
+    /**
+     * Multiplies an element by a vector of it.
+     *
+     * @receiver the multiplicand.
+     * @param v the multiplier.
+     * @receiver the product.
+     */
+    public operator fun T.times(v: Point<T>): Point<T> = v * this
+
+    /**
+     * Get a feature of the structure in this scope. Structure features take precedence other context features
+     *
+     * @param F the type of feature.
+     * @param structure the structure.
+     * @param type the [KClass] instance of [F].
+     * @return a feature object or `null` if it isn't present.
+     */
+    @UnstableKMathAPI
+    public fun <F : Any> getFeature(structure: Matrix<T>, type: KClass<F>): F? = structure.getFeature(type)
+
+    public companion object {
+
+        /**
+         * A structured matrix with custom buffer
+         */
+        public fun <T : Any, A : Ring<T>> buffered(
+            algebra: A,
+            bufferFactory: BufferFactory<T> = Buffer.Companion::boxing,
+        ): LinearSpace<T, A> = BufferedLinearSpace(algebra, bufferFactory)
+
+        public val real: LinearSpace<Double, DoubleField> = buffered(DoubleField, ::DoubleBuffer)
+
+        /**
+         * Automatic buffered matrix, unboxed if it is possible
+         */
+        public inline fun <reified T : Any, A : Ring<T>> auto(ring: A): LinearSpace<T, A> =
+            buffered(ring, Buffer.Companion::auto)
+    }
+}
+
+/**
+ * Get a feature of the structure in this scope. Structure features take precedence other context features
+ *
+ * @param T the type of items in the matrices.
+ * @param F the type of feature.
+ * @return a feature object or `null` if it isn't present.
+ */
+@UnstableKMathAPI
+public inline fun <T : Any, reified F : Any> LinearSpace<T, *>.getFeature(structure: Matrix<T>): F? =
+    getFeature(structure, F::class)
+
+
+public operator fun <LS : LinearSpace<*, *>, R> LS.invoke(block: LS.() -> R): R = run(block)
+

kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/LupDecomposition.kt

@@ -3,8 +3,8 @@ package space.kscience.kmath.linear
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.nd.getFeature
 import space.kscience.kmath.operations.*
-import space.kscience.kmath.structures.Buffer
 import space.kscience.kmath.structures.BufferAccessor2D
+import space.kscience.kmath.structures.DoubleBuffer
 import space.kscience.kmath.structures.MutableBuffer
 import space.kscience.kmath.structures.MutableBufferFactory
 
@@ -12,7 +12,7 @@ import space.kscience.kmath.structures.MutableBufferFactory
  * Common implementation of [LupDecompositionFeature].
  */
 public class LupDecomposition<T : Any>(
-    public val context: MatrixContext<T, Matrix<T>>,
+    public val context: LinearSpace<T, *>,
     public val elementContext: Field<T>,
     public val lu: Matrix<T>,
     public val pivot: IntArray,
@@ -62,15 +62,14 @@ public class LupDecomposition<T : Any>(
 }
 
 @PublishedApi
-internal fun <T : Comparable<T>, F : Field<T>> GenericMatrixContext<T, F, *>.abs(value: T): T =
+internal fun <T : Comparable<T>> LinearSpace<T, Ring<T>>.abs(value: T): T =
-    if (value > elementContext.zero) value else elementContext { -value }
+    if (value > elementAlgebra.zero) value else elementAlgebra { -value }
 
 /**
  * Create a lup decomposition of generic matrix.
  */
-public fun <T : Comparable<T>> MatrixContext<T, Matrix<T>>.lup(
+public fun <T : Comparable<T>> LinearSpace<T, Field<T>>.lup(
     factory: MutableBufferFactory<T>,
-    elementContext: Field<T>,
     matrix: Matrix<T>,
     checkSingular: (T) -> Boolean,
 ): LupDecomposition<T> {
@@ -80,7 +79,7 @@ public fun <T : Comparable<T>> MatrixContext<T, Matrix<T>>.lup(
 
     //TODO just waits for KEEP-176
     BufferAccessor2D(matrix.rowNum, matrix.colNum, factory).run {
-        elementContext {
+        elementAlgebra {
             val lu = create(matrix)
 
             // Initialize permutation array and parity
@@ -142,18 +141,18 @@ public fun <T : Comparable<T>> MatrixContext<T, Matrix<T>>.lup(
                 for (row in col + 1 until m) lu[row, col] /= luDiag
             }
 
-            return LupDecomposition(this@lup, elementContext, lu.collect(), pivot, even)
+            return LupDecomposition(this@lup, elementAlgebra, lu.collect(), pivot, even)
         }
     }
 }
 
-public inline fun <reified T : Comparable<T>, F : Field<T>> GenericMatrixContext<T, F, Matrix<T>>.lup(
+public inline fun <reified T : Comparable<T>> LinearSpace<T, Field<T>>.lup(
     matrix: Matrix<T>,
     noinline checkSingular: (T) -> Boolean,
-): LupDecomposition<T> = lup(MutableBuffer.Companion::auto, elementContext, matrix, checkSingular)
+): LupDecomposition<T> = lup(MutableBuffer.Companion::auto, matrix, checkSingular)
 
-public fun MatrixContext<Double, Matrix<Double>>.lup(matrix: Matrix<Double>): LupDecomposition<Double> =
+public fun LinearSpace<Double, DoubleField>.lup(matrix: Matrix<Double>): LupDecomposition<Double> =
-    lup(Buffer.Companion::real, RealField, matrix) { it < 1e-11 }
+    lup(::DoubleBuffer, matrix) { it < 1e-11 }
 
 public fun <T : Any> LupDecomposition<T>.solveWithLup(
     factory: MutableBufferFactory<T>,
@@ -198,7 +197,7 @@ public fun <T : Any> LupDecomposition<T>.solveWithLup(
                 }
             }
 
-            return context.produce(pivot.size, matrix.colNum) { i, j -> bp[i, j] }
+            return context.buildMatrix(pivot.size, matrix.colNum) { i, j -> bp[i, j] }
         }
     }
 }
@@ -210,18 +209,18 @@ public inline fun <reified T : Any> LupDecomposition<T>.solveWithLup(matrix: Mat
  * Solves a system of linear equations *ax = b** using LUP decomposition.
  */
 @OptIn(UnstableKMathAPI::class)
-public inline fun <reified T : Comparable<T>, F : Field<T>> GenericMatrixContext<T, F, Matrix<T>>.solveWithLup(
+public inline fun <reified T : Comparable<T>> LinearSpace<T, Field<T>>.solveWithLup(
     a: Matrix<T>,
     b: Matrix<T>,
     noinline bufferFactory: MutableBufferFactory<T> = MutableBuffer.Companion::auto,
     noinline checkSingular: (T) -> Boolean,
 ): Matrix<T> {
     // Use existing decomposition if it is provided by matrix
-    val decomposition = a.getFeature() ?: lup(bufferFactory, elementContext, a, checkSingular)
+    val decomposition = a.getFeature() ?: lup(bufferFactory, a, checkSingular)
     return decomposition.solveWithLup(bufferFactory, b)
 }
 
-public inline fun <reified T : Comparable<T>, F : Field<T>> GenericMatrixContext<T, F, Matrix<T>>.inverseWithLup(
+public inline fun <reified T : Comparable<T>> LinearSpace<T, Field<T>>.inverseWithLup(
     matrix: Matrix<T>,
     noinline bufferFactory: MutableBufferFactory<T> = MutableBuffer.Companion::auto,
     noinline checkSingular: (T) -> Boolean,
@@ -229,15 +228,15 @@ public inline fun <reified T : Comparable<T>, F : Field<T>> GenericMatrixContext
 
 
 @OptIn(UnstableKMathAPI::class)
-public fun RealMatrixContext.solveWithLup(a: Matrix<Double>, b: Matrix<Double>): Matrix<Double> {
+public fun LinearSpace<Double, DoubleField>.solveWithLup(a: Matrix<Double>, b: Matrix<Double>): Matrix<Double> {
     // Use existing decomposition if it is provided by matrix
-    val bufferFactory: MutableBufferFactory<Double> = MutableBuffer.Companion::real
+    val bufferFactory: MutableBufferFactory<Double> = ::DoubleBuffer
-    val decomposition: LupDecomposition<Double> = a.getFeature() ?: lup(bufferFactory, RealField, a) { it < 1e-11 }
+    val decomposition: LupDecomposition<Double> = a.getFeature() ?: lup(bufferFactory, a) { it < 1e-11 }
     return decomposition.solveWithLup(bufferFactory, b)
 }
 
 /**
  * Inverses a square matrix using LUP decomposition. Non square matrix will throw a error.
  */
-public fun RealMatrixContext.inverseWithLup(matrix: Matrix<Double>): Matrix<Double> =
+public fun LinearSpace<Double, DoubleField>.inverseWithLup(matrix: Matrix<Double>): Matrix<Double> =
     solveWithLup(matrix, one(matrix.rowNum, matrix.colNum))

kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/MatrixBuilder.kt

@@ -1,46 +1,43 @@
 package space.kscience.kmath.linear
 
-import space.kscience.kmath.nd.Structure2D
+import space.kscience.kmath.misc.UnstableKMathAPI
-import space.kscience.kmath.structures.Buffer
+import space.kscience.kmath.operations.Ring
-import space.kscience.kmath.structures.BufferFactory
-import space.kscience.kmath.structures.asBuffer
 
-public class MatrixBuilder(public val rows: Int, public val columns: Int) {
+public class MatrixBuilder<T : Any, A : Ring<T>>(
-    public operator fun <T : Any> invoke(vararg elements: T): Matrix<T> {
+    public val linearSpace: LinearSpace<T, A>,
+    public val rows: Int,
+    public val columns: Int,
+) {
+    public operator fun invoke(vararg elements: T): Matrix<T> {
         require(rows * columns == elements.size) { "The number of elements ${elements.size} is not equal $rows * $columns" }
-        val buffer = elements.asBuffer()
+        return linearSpace.buildMatrix(rows, columns) { i, j -> elements[i * columns + j] }
-        return BufferMatrix(rows, columns, buffer)
     }
 
     //TODO add specific matrix builder functions like diagonal, etc
 }
 
-public fun Structure2D.Companion.build(rows: Int, columns: Int): MatrixBuilder = MatrixBuilder(rows, columns)
+/**
+ * Create a matrix builder with given number of rows and columns
+ */
+@UnstableKMathAPI
+public fun <T : Any, A : Ring<T>> LinearSpace<T, A>.matrix(rows: Int, columns: Int): MatrixBuilder<T, A> =
+    MatrixBuilder(this, rows, columns)
 
-public fun <T : Any> Structure2D.Companion.row(vararg values: T): Matrix<T> {
+@UnstableKMathAPI
-    val buffer = values.asBuffer()
+public fun <T : Any> LinearSpace<T, Ring<T>>.vector(vararg elements: T): Point<T> {
-    return BufferMatrix(1, values.size, buffer)
+    return buildVector(elements.size) { elements[it] }
 }
 
-public inline fun <reified T : Any> Structure2D.Companion.row(
+public inline fun <T : Any> LinearSpace<T, Ring<T>>.row(
     size: Int,
-    factory: BufferFactory<T> = Buffer.Companion::auto,
+    crossinline builder: (Int) -> T,
-    noinline builder: (Int) -> T,
+): Matrix<T> = buildMatrix(1, size) { _, j -> builder(j) }
-): Matrix<T> {
-    val buffer = factory(size, builder)
-    return BufferMatrix(1, size, buffer)
-}
 
-public fun <T : Any> Structure2D.Companion.column(vararg values: T): Matrix<T> {
+public fun <T : Any> LinearSpace<T, Ring<T>>.row(vararg values: T): Matrix<T> = row(values.size, values::get)
-    val buffer = values.asBuffer()
-    return BufferMatrix(values.size, 1, buffer)
-}
 
-public inline fun <reified T : Any> Structure2D.Companion.column(
+public inline fun <T : Any> LinearSpace<T, Ring<T>>.column(
     size: Int,
-    factory: BufferFactory<T> = Buffer.Companion::auto,
+    crossinline builder: (Int) -> T,
-    noinline builder: (Int) -> T,
+): Matrix<T> = buildMatrix(size, 1) { i, _ -> builder(i) }
-): Matrix<T> {
+
-    val buffer = factory(size, builder)
+public fun <T : Any> LinearSpace<T, Ring<T>>.column(vararg values: T): Matrix<T> = column(values.size, values::get)
-    return BufferMatrix(size, 1, buffer)
-}

kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/MatrixContext.kt

@@ -1,173 +0,0 @@
-package space.kscience.kmath.linear
-
-import space.kscience.kmath.misc.UnstableKMathAPI
-import space.kscience.kmath.operations.*
-import space.kscience.kmath.structures.Buffer
-import space.kscience.kmath.structures.BufferFactory
-import space.kscience.kmath.structures.asSequence
-import kotlin.reflect.KClass
-
-/**
- * Basic operations on matrices. Operates on [Matrix].
- *
- * @param T the type of items in the matrices.
- * @param M the type of operated matrices.
- */
-public interface MatrixContext<T : Any, out M : Matrix<T>> : GroupOperations<Matrix<T>>, ScaleOperations<Matrix<T>> {
-    /**
-     * Produces a matrix with this context and given dimensions.
-     */
-    public fun produce(rows: Int, columns: Int, initializer: (i: Int, j: Int) -> T): M
-
-    /**
-     * Produces a point compatible with matrix space (and possibly optimized for it).
-     */
-    public fun point(size: Int, initializer: (Int) -> T): Point<T> = Buffer.boxing(size, initializer)
-
-    @Suppress("UNCHECKED_CAST")
-    public override fun binaryOperationFunction(operation: String): (left: Matrix<T>, right: Matrix<T>) -> M =
-        when (operation) {
-            "dot" -> { left, right -> left dot right }
-            else -> super<GroupOperations>.binaryOperationFunction(operation) as (Matrix<T>, Matrix<T>) -> M
-        }
-
-    /**
-     * Computes the dot product of this matrix and another one.
-     *
-     * @receiver the multiplicand.
-     * @param other the multiplier.
-     * @return the dot product.
-     */
-    public infix fun Matrix<T>.dot(other: Matrix<T>): M
-
-    /**
-     * Computes the dot product of this matrix and a vector.
-     *
-     * @receiver the multiplicand.
-     * @param vector the multiplier.
-     * @return the dot product.
-     */
-    public infix fun Matrix<T>.dot(vector: Point<T>): Point<T>
-
-    /**
-     * Multiplies a matrix by its element.
-     *
-     * @receiver the multiplicand.
-     * @param value the multiplier.
-     * @receiver the product.
-     */
-    public operator fun Matrix<T>.times(value: T): M
-
-    /**
-     * Multiplies an element by a matrix of it.
-     *
-     * @receiver the multiplicand.
-     * @param m the multiplier.
-     * @receiver the product.
-     */
-    public operator fun T.times(m: Matrix<T>): M = m * this
-
-    /**
-     * Gets a feature from the matrix. This function may return some additional features to
-     * [kscience.kmath.nd.NDStructure.getFeature].
-     *
-     * @param F the type of feature.
-     * @param m the matrix.
-     * @param type the [KClass] instance of [F].
-     * @return a feature object or `null` if it isn't present.
-     */
-    @UnstableKMathAPI
-    public fun <F : Any> getFeature(m: Matrix<T>, type: KClass<F>): F? = m.getFeature(type)
-
-    public companion object {
-
-        /**
-         * A structured matrix with custom buffer
-         */
-        public fun <T : Any, A> buffered(
-            ring: A,
-            bufferFactory: BufferFactory<T> = Buffer.Companion::boxing,
-        ): GenericMatrixContext<T, A, BufferMatrix<T>> where A : Ring<T>, A: ScaleOperations<T> = BufferMatrixContext(ring, bufferFactory)
-
-        /**
-         * Automatic buffered matrix, unboxed if it is possible
-         */
-        public inline fun <reified T : Any, A> auto(ring: A): GenericMatrixContext<T, A, BufferMatrix<T>> where A : Ring<T>, A: ScaleOperations<T> =
-            buffered(ring, Buffer.Companion::auto)
-    }
-}
-
-/**
- * Gets a feature from the matrix. This function may return some additional features to
- * [kscience.kmath.nd.NDStructure.getFeature].
- *
- * @param T the type of items in the matrices.
- * @param M the type of operated matrices.
- * @param F the type of feature.
- * @receiver the [MatrixContext] of [T].
- * @param m the matrix.
- * @return a feature object or `null` if it isn't present.
- */
-@UnstableKMathAPI
-public inline fun <T : Any, reified F : Any> MatrixContext<T, *>.getFeature(m: Matrix<T>): F? =
-    getFeature(m, F::class)
-
-/**
- * Partial implementation of [MatrixContext] for matrices of [Ring].
- *
- * @param T the type of items in the matrices.
- * @param A the type of ring of matrix elements.
- * @param M the type of operated matrices.
- */
-public interface GenericMatrixContext<T : Any, A, out M : Matrix<T>> : MatrixContext<T, M> where A : Ring<T>, A : ScaleOperations<T>{
-    /**
-     * The ring over matrix elements.
-     */
-    public val elementContext: A
-
-    public override infix fun Matrix<T>.dot(other: Matrix<T>): M {
-        //TODO add typed error
-        require(colNum == other.rowNum) { "Matrix dot operation dimension mismatch: ($rowNum, $colNum) x (${other.rowNum}, ${other.colNum})" }
-
-        return produce(rowNum, other.colNum) { i, j ->
-            val row = rows[i]
-            val column = other.columns[j]
-            elementContext { sum(row.asSequence().zip(column.asSequence(), ::multiply)) }
-        }
-    }
-
-    public override infix fun Matrix<T>.dot(vector: Point<T>): Point<T> {
-        //TODO add typed error
-        require(colNum == vector.size) { "Matrix dot vector operation dimension mismatch: ($rowNum, $colNum) x (${vector.size})" }
-
-        return point(rowNum) { i ->
-            val row = rows[i]
-            elementContext { sum(row.asSequence().zip(vector.asSequence(), ::multiply)) }
-        }
-    }
-
-    public override operator fun Matrix<T>.unaryMinus(): M =
-        produce(rowNum, colNum) { i, j -> elementContext { -get(i, j) } }
-
-    public override fun add(a: Matrix<T>, b: Matrix<T>): M {
-        require(a.rowNum == b.rowNum && a.colNum == b.colNum) {
-            "Matrix operation dimension mismatch. [${a.rowNum},${a.colNum}] + [${b.rowNum},${b.colNum}]"
-        }
-
-        return produce(a.rowNum, a.colNum) { i, j -> elementContext { a[i, j] + b[i, j] } }
-    }
-
-    public override operator fun Matrix<T>.minus(b: Matrix<T>): M {
-        require(rowNum == b.rowNum && colNum == b.colNum) {
-            "Matrix operation dimension mismatch. [$rowNum,$colNum] - [${b.rowNum},${b.colNum}]"
-        }
-
-        return produce(rowNum, colNum) { i, j -> elementContext { get(i, j) + b[i, j] } }
-    }
-//
-//    public override fun multiply(a: Matrix<T>, k: Number): M =
-//        produce(a.rowNum, a.colNum) { i, j -> elementContext { a[i, j] * k } }
-
-    public override operator fun Matrix<T>.times(value: T): M =
-        produce(rowNum, colNum) { i, j -> elementContext { get(i, j) * value } }
-}

kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/MatrixWrapper.kt

@@ -1,14 +1,9 @@
 package space.kscience.kmath.linear
 
 import space.kscience.kmath.misc.UnstableKMathAPI
-import space.kscience.kmath.nd.Structure2D
 import space.kscience.kmath.nd.getFeature
 import space.kscience.kmath.operations.Ring
-import space.kscience.kmath.operations.ScaleOperations
-import space.kscience.kmath.structures.asBuffer
-import kotlin.math.sqrt
 import kotlin.reflect.KClass
-import kotlin.reflect.safeCast
 
 /**
  * A [Matrix] that holds [MatrixFeature] objects.
@@ -24,11 +19,10 @@ public class MatrixWrapper<T : Any> internal constructor(
      * Get the first feature matching given class. Does not guarantee that matrix has only one feature matching the criteria
      */
     @UnstableKMathAPI
-    override fun <T : Any> getFeature(type: KClass<T>): T? = type.safeCast(features.find { type.isInstance(it) })
+    @Suppress("UNCHECKED_CAST")
+    override fun <T : Any> getFeature(type: KClass<T>): T? = features.singleOrNull { type.isInstance(it) } as? T
         ?: origin.getFeature(type)
 
-    override fun equals(other: Any?): Boolean = origin == other
-    override fun hashCode(): Int = origin.hashCode()
     override fun toString(): String {
         return "MatrixWrapper(matrix=$origin, features=$features)"
     }
@@ -61,35 +55,25 @@ public operator fun <T : Any> Matrix<T>.plus(newFeatures: Collection<MatrixFeatu
         MatrixWrapper(this, newFeatures.toSet())
     }
 
-/**
- * Build a square matrix from given elements.
- */
-public fun <T : Any> Structure2D.Companion.square(vararg elements: T): Matrix<T> {
-    val size: Int = sqrt(elements.size.toDouble()).toInt()
-    require(size * size == elements.size) { "The number of elements ${elements.size} is not a full square" }
-    val buffer = elements.asBuffer()
-    return BufferMatrix(size, size, buffer)
-}
-
 /**
  * Diagonal matrix of ones. The matrix is virtual no actual matrix is created
  */
-public fun <T : Any, A> GenericMatrixContext<T, A, *>.one(
+public fun <T : Any> LinearSpace<T, Ring<T>>.one(
     rows: Int,
     columns: Int,
-): Matrix<T> where A : Ring<T>, A : ScaleOperations<T> = VirtualMatrix(rows, columns) { i, j ->
+): Matrix<T> = VirtualMatrix(rows, columns) { i, j ->
-    if (i == j) elementContext.one else elementContext.zero
+    if (i == j) elementAlgebra.one else elementAlgebra.zero
 } + UnitFeature
 
 
 /**
  * A virtual matrix of zeroes
  */
-public fun <T : Any, A> GenericMatrixContext<T, A, *>.zero(
+public fun <T : Any> LinearSpace<T, Ring<T>>.zero(
     rows: Int,
     columns: Int,
-): Matrix<T> where A : Ring<T>, A : ScaleOperations<T> = VirtualMatrix(rows, columns) { _, _ ->
+): Matrix<T> = VirtualMatrix(rows, columns) { _, _ ->
-    elementContext.zero
+    elementAlgebra.zero
 } + ZeroFeature
 
 public class TransposedFeature<T : Any>(public val original: Matrix<T>) : MatrixFeature

kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/RealMatrixContext.kt

@@ -1,85 +0,0 @@
-package space.kscience.kmath.linear
-
-import space.kscience.kmath.operations.ScaleOperations
-import space.kscience.kmath.structures.RealBuffer
-
-public object RealMatrixContext : MatrixContext<Double, BufferMatrix<Double>>, ScaleOperations<Matrix<Double>> {
-
-    public override fun produce(
-        rows: Int,
-        columns: Int,
-        initializer: (i: Int, j: Int) -> Double,
-    ): BufferMatrix<Double> {
-        val buffer = RealBuffer(rows * columns) { offset -> initializer(offset / columns, offset % columns) }
-        return BufferMatrix(rows, columns, buffer)
-    }
-
-    public fun Matrix<Double>.toBufferMatrix(): BufferMatrix<Double> = if (this is BufferMatrix) this else {
-        produce(rowNum, colNum) { i, j -> get(i, j) }
-    }
-
-    public fun one(rows: Int, columns: Int): Matrix<Double> = VirtualMatrix(rows, columns) { i, j ->
-        if (i == j) 1.0 else 0.0
-    } + DiagonalFeature
-
-    override fun Matrix<Double>.unaryMinus(): Matrix<Double> = produce(rowNum, colNum) { i, j -> -get(i, j) }
-
-    public override infix fun Matrix<Double>.dot(other: Matrix<Double>): BufferMatrix<Double> {
-        require(colNum == other.rowNum) { "Matrix dot operation dimension mismatch: ($rowNum, $colNum) x (${other.rowNum}, ${other.colNum})" }
-        val bufferMatrix = toBufferMatrix()
-        val otherBufferMatrix = other.toBufferMatrix()
-        return produce(rowNum, other.colNum) { i, j ->
-            var res = 0.0
-            for (l in 0 until colNum) {
-                res += bufferMatrix[i, l] * otherBufferMatrix[l, j]
-            }
-            res
-        }
-    }
-
-    public override infix fun Matrix<Double>.dot(vector: Point<Double>): Point<Double> {
-        require(colNum == vector.size) { "Matrix dot vector operation dimension mismatch: ($rowNum, $colNum) x (${vector.size})" }
-        val bufferMatrix = toBufferMatrix()
-        return RealBuffer(rowNum) { i ->
-            var res = 0.0
-            for (j in 0 until colNum) {
-                res += bufferMatrix[i, j] * vector[j]
-            }
-            res
-        }
-    }
-
-    override fun add(a: Matrix<Double>, b: Matrix<Double>): BufferMatrix<Double> {
-        require(a.rowNum == b.rowNum) { "Row number mismatch in matrix addition. Left side: ${a.rowNum}, right side: ${b.rowNum}" }
-        require(a.colNum == b.colNum) { "Column number mismatch in matrix addition. Left side: ${a.colNum}, right side: ${b.colNum}" }
-        val aBufferMatrix = a.toBufferMatrix()
-        val bBufferMatrix = b.toBufferMatrix()
-        return produce(a.rowNum, a.colNum) { i, j ->
-            aBufferMatrix[i, j] + bBufferMatrix[i, j]
-        }
-    }
-
-    override fun scale(a: Matrix<Double>, value: Double): BufferMatrix<Double> {
-        val bufferMatrix = a.toBufferMatrix()
-        return produce(a.rowNum, a.colNum) { i, j -> bufferMatrix[i, j] * value }
-    }
-
-    override fun Matrix<Double>.times(value: Double): BufferMatrix<Double> = scale(this, value)
-
-//
-//    override fun multiply(a: Matrix<Double>, k: Number): BufferMatrix<Double> {
-//        val aBufferMatrix = a.toBufferMatrix()
-//        return produce(a.rowNum, a.colNum) { i, j -> aBufferMatrix[i, j] * k.toDouble() }
-//    }
-//
-//    override fun divide(a: Matrix<Double>, k: Number): BufferMatrix<Double> {
-//        val aBufferMatrix = a.toBufferMatrix()
-//        return produce(a.rowNum, a.colNum) { i, j -> aBufferMatrix[i, j] / k.toDouble() }
-//    }
-}
-
-
-/**
- * Partially optimized real-valued matrix
- */
-public val MatrixContext.Companion.real: RealMatrixContext get() = RealMatrixContext

kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/VectorSpace.kt

@@ -1,72 +0,0 @@
-package space.kscience.kmath.linear
-
-import space.kscience.kmath.operations.Group
-import space.kscience.kmath.operations.RealField
-import space.kscience.kmath.operations.ScaleOperations
-import space.kscience.kmath.operations.invoke
-import space.kscience.kmath.structures.Buffer
-import space.kscience.kmath.structures.BufferFactory
-
-/**
- * A linear space for vectors.
- * Could be used on any point-like structure
- */
-public interface VectorSpace<T : Any, A> : Group<Point<T>>, ScaleOperations<Point<T>>
-        where A : Group<T>, A : ScaleOperations<T> {
-    public val size: Int
-    public val algebra: A
-    override val zero: Point<T> get() = produce { algebra.zero }
-
-    public fun produce(initializer: A.(Int) -> T): Point<T>
-
-    override fun add(a: Point<T>, b: Point<T>): Point<T> = produce { algebra { a[it] + b[it] } }
-
-    override fun scale(a: Point<T>, value: Double): Point<T> = produce { algebra.scale(a[it], value) }
-
-    override fun Point<T>.unaryMinus(): Point<T> = produce { -get(it) }
-
-    //TODO add basis
-
-    public companion object {
-        private val realSpaceCache: MutableMap<Int, BufferVectorSpace<Double, RealField>> = hashMapOf()
-
-        /**
-         * Non-boxing double vector space
-         */
-        public fun real(size: Int): BufferVectorSpace<Double, RealField> = realSpaceCache.getOrPut(size) {
-            BufferVectorSpace(
-                size,
-                RealField,
-                Buffer.Companion::auto
-            )
-        }
-
-        /**
-         * A structured vector space with custom buffer
-         */
-        public fun <T : Any, A> buffered(
-            size: Int,
-            space: A,
-            bufferFactory: BufferFactory<T> = Buffer.Companion::boxing,
-        ): BufferVectorSpace<T, A> where A : Group<T>, A : ScaleOperations<T> =
-            BufferVectorSpace(size, space, bufferFactory)
-
-        /**
-         * Automatic buffered vector, unboxed if it is possible
-         */
-        public inline fun <reified T : Any, A> auto(
-            size: Int,
-            space: A,
-        ): VectorSpace<T, A> where A : Group<T>, A : ScaleOperations<T> =
-            buffered(size, space, Buffer.Companion::auto)
-    }
-}
-
-
-public class BufferVectorSpace<T : Any, A>(
-    override val size: Int,
-    override val algebra: A,
-    public val bufferFactory: BufferFactory<T>,
-) : VectorSpace<T, A> where A : Group<T>, A : ScaleOperations<T> {
-    override fun produce(initializer: A.(Int) -> T): Buffer<T> = bufferFactory(size) { algebra.initializer(it) }
-}

kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/VirtualMatrix.kt

@@ -8,29 +8,10 @@ package space.kscience.kmath.linear
 public class VirtualMatrix<T : Any>(
     override val rowNum: Int,
     override val colNum: Int,
-    public val generator: (i: Int, j: Int) -> T
+    public val generator: (i: Int, j: Int) -> T,
 ) : Matrix<T> {
 
     override val shape: IntArray get() = intArrayOf(rowNum, colNum)
 
     override operator fun get(i: Int, j: Int): T = generator(i, j)
-
-    override fun equals(other: Any?): Boolean {
-        if (this === other) return true
-        if (other !is Matrix<*>) return false
-
-        if (rowNum != other.rowNum) return false
-        if (colNum != other.colNum) return false
-
-        return elements().all { (index, value) -> value == other[index] }
-    }
-
-    override fun hashCode(): Int {
-        var result = rowNum
-        result = 31 * result + colNum
-        result = 31 * result + generator.hashCode()
-        return result
-    }
-
-
 }

kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/AlgebraND.kt

@@ -1,7 +1,9 @@
 package space.kscience.kmath.nd
 
+import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.operations.*
 import space.kscience.kmath.structures.*
+import kotlin.reflect.KClass
 
 /**
  * An exception is thrown when the expected ans actual shape of NDArray differs.
@@ -19,7 +21,7 @@ public class ShapeMismatchException(public val expected: IntArray, public val ac
  * @param C the type of the element context.
  * @param N the type of the structure.
  */
-public interface NDAlgebra<T, C: Algebra<T>> {
+public interface AlgebraND<T, C : Algebra<T>> {
     /**
      * The shape of ND-structures this algebra operates on.
      */
@@ -33,42 +35,66 @@ public interface NDAlgebra<T, C: Algebra<T>> {
     /**
      * Produces a new NDStructure using given initializer function.
      */
-    public fun produce(initializer: C.(IntArray) -> T): NDStructure<T>
+    public fun produce(initializer: C.(IntArray) -> T): StructureND<T>
 
     /**
      * Maps elements from one structure to another one by applying [transform] to them.
      */
-    public fun NDStructure<T>.map(transform: C.(T) -> T): NDStructure<T>
+    public fun StructureND<T>.map(transform: C.(T) -> T): StructureND<T>
 
     /**
      * Maps elements from one structure to another one by applying [transform] to them alongside with their indices.
      */
-    public fun NDStructure<T>.mapIndexed(transform: C.(index: IntArray, T) -> T): NDStructure<T>
+    public fun StructureND<T>.mapIndexed(transform: C.(index: IntArray, T) -> T): StructureND<T>
 
     /**
      * Combines two structures into one.
      */
-    public fun combine(a: NDStructure<T>, b: NDStructure<T>, transform: C.(T, T) -> T): NDStructure<T>
+    public fun combine(a: StructureND<T>, b: StructureND<T>, transform: C.(T, T) -> T): StructureND<T>
 
     /**
-     * Element-wise invocation of function working on [T] on a [NDStructure].
+     * Element-wise invocation of function working on [T] on a [StructureND].
      */
-    public operator fun Function1<T, T>.invoke(structure: NDStructure<T>): NDStructure<T> =
+    public operator fun Function1<T, T>.invoke(structure: StructureND<T>): StructureND<T> =
         structure.map { value -> this@invoke(value) }
 
+    /**
+     * Get a feature of the structure in this scope. Structure features take precedence other context features
+     *
+     * @param F the type of feature.
+     * @param structure the structure.
+     * @param type the [KClass] instance of [F].
+     * @return a feature object or `null` if it isn't present.
+     */
+    @UnstableKMathAPI
+    public fun <F : Any> getFeature(structure: StructureND<T>, type: KClass<F>): F? = structure.getFeature(type)
+
     public companion object
 }
 
+
+/**
+ * Get a feature of the structure in this scope. Structure features take precedence other context features
+ *
+ * @param T the type of items in the matrices.
+ * @param F the type of feature.
+ * @return a feature object or `null` if it isn't present.
+ */
+@UnstableKMathAPI
+public inline fun <T : Any, reified F : Any> AlgebraND<T, *>.getFeature(structure: StructureND<T>): F? =
+    getFeature(structure, F::class)
+
 /**
  * Checks if given elements are consistent with this context.
  *
  * @param structures the structures to check.
  * @return the array of valid structures.
  */
-internal fun <T, C: Algebra<T>> NDAlgebra<T, C>.checkShape(vararg structures: NDStructure<T>): Array<out NDStructure<T>> = structures
+internal fun <T, C : Algebra<T>> AlgebraND<T, C>.checkShape(vararg structures: StructureND<T>): Array<out StructureND<T>> =
-    .map(NDStructure<T>::shape)
+    structures
+        .map(StructureND<T>::shape)
         .singleOrNull { !shape.contentEquals(it) }
-    ?.let<IntArray, Array<out NDStructure<T>>> { throw ShapeMismatchException(shape, it) }
+        ?.let<IntArray, Array<out StructureND<T>>> { throw ShapeMismatchException(shape, it) }
         ?: structures
 
 /**
@@ -77,19 +103,19 @@ internal fun <T, C: Algebra<T>> NDAlgebra<T, C>.checkShape(vararg structures: ND
  * @param element the structure to check.
  * @return the valid structure.
  */
-internal fun <T, C: Algebra<T>> NDAlgebra<T, C>.checkShape(element: NDStructure<T>): NDStructure<T> {
+internal fun <T, C : Algebra<T>> AlgebraND<T, C>.checkShape(element: StructureND<T>): StructureND<T> {
     if (!element.shape.contentEquals(shape)) throw ShapeMismatchException(shape, element.shape)
     return element
 }
 
 /**
- * Space of [NDStructure].
+ * Space of [StructureND].
  *
  * @param T the type of the element contained in ND structure.
  * @param N the type of ND structure.
  * @param S the type of space of structure elements.
  */
-public interface NDGroup<T, S : Group<T>> : Group<NDStructure<T>>, NDAlgebra<T, S> {
+public interface GroupND<T, S : Group<T>> : Group<StructureND<T>>, AlgebraND<T, S> {
     /**
      * Element-wise addition.
      *
@@ -97,7 +123,7 @@ public interface NDGroup<T, S : Group<T>> : Group<NDStructure<T>>, NDAlgebra<T,
      * @param b the augend.
      * @return the sum.
      */
-    public override fun add(a: NDStructure<T>, b: NDStructure<T>): NDStructure<T> =
+    public override fun add(a: StructureND<T>, b: StructureND<T>): StructureND<T> =
         combine(a, b) { aValue, bValue -> add(aValue, bValue) }
 
 //    /**
@@ -118,7 +144,7 @@ public interface NDGroup<T, S : Group<T>> : Group<NDStructure<T>>, NDAlgebra<T,
      * @param arg the augend.
      * @return the sum.
      */
-    public operator fun NDStructure<T>.plus(arg: T): NDStructure<T> = this.map { value -> add(arg, value) }
+    public operator fun StructureND<T>.plus(arg: T): StructureND<T> = this.map { value -> add(arg, value) }
 
     /**
      * Subtracts an element from ND structure of it.
@@ -127,7 +153,7 @@ public interface NDGroup<T, S : Group<T>> : Group<NDStructure<T>>, NDAlgebra<T,
      * @param arg the divisor.
      * @return the quotient.
      */
-    public operator fun NDStructure<T>.minus(arg: T): NDStructure<T> = this.map { value -> add(arg, -value) }
+    public operator fun StructureND<T>.minus(arg: T): StructureND<T> = this.map { value -> add(arg, -value) }
 
     /**
      * Adds an element to ND structure of it.
@@ -136,7 +162,7 @@ public interface NDGroup<T, S : Group<T>> : Group<NDStructure<T>>, NDAlgebra<T,
      * @param arg the augend.
      * @return the sum.
      */
-    public operator fun T.plus(arg: NDStructure<T>): NDStructure<T> = arg.map { value -> add(this@plus, value) }
+    public operator fun T.plus(arg: StructureND<T>): StructureND<T> = arg.map { value -> add(this@plus, value) }
 
     /**
      * Subtracts an ND structure from an element of it.
@@ -145,19 +171,19 @@ public interface NDGroup<T, S : Group<T>> : Group<NDStructure<T>>, NDAlgebra<T,
      * @param arg the divisor.
      * @return the quotient.
      */
-    public operator fun T.minus(arg: NDStructure<T>): NDStructure<T> = arg.map { value -> add(-this@minus, value) }
+    public operator fun T.minus(arg: StructureND<T>): StructureND<T> = arg.map { value -> add(-this@minus, value) }
 
     public companion object
 }
 
 /**
- * Ring of [NDStructure].
+ * Ring of [StructureND].
  *
  * @param T the type of the element contained in ND structure.
  * @param N the type of ND structure.
  * @param R the type of ring of structure elements.
  */
-public interface NDRing<T, R : Ring<T>> : Ring<NDStructure<T>>, NDGroup<T, R> {
+public interface RingND<T, R : Ring<T>> : Ring<StructureND<T>>, GroupND<T, R> {
     /**
      * Element-wise multiplication.
      *
@@ -165,7 +191,7 @@ public interface NDRing<T, R : Ring<T>> : Ring<NDStructure<T>>, NDGroup<T, R> {
      * @param b the multiplier.
      * @return the product.
      */
-    public override fun multiply(a: NDStructure<T>, b: NDStructure<T>): NDStructure<T> =
+    public override fun multiply(a: StructureND<T>, b: StructureND<T>): StructureND<T> =
         combine(a, b) { aValue, bValue -> multiply(aValue, bValue) }
 
     //TODO move to extensions after KEEP-176
@@ -177,7 +203,7 @@ public interface NDRing<T, R : Ring<T>> : Ring<NDStructure<T>>, NDGroup<T, R> {
      * @param arg the multiplier.
      * @return the product.
      */
-    public operator fun NDStructure<T>.times(arg: T): NDStructure<T> = this.map { value -> multiply(arg, value) }
+    public operator fun StructureND<T>.times(arg: T): StructureND<T> = this.map { value -> multiply(arg, value) }
 
     /**
      * Multiplies an element by a ND structure of it.
@@ -186,19 +212,19 @@ public interface NDRing<T, R : Ring<T>> : Ring<NDStructure<T>>, NDGroup<T, R> {
      * @param arg the multiplier.
      * @return the product.
      */
-    public operator fun T.times(arg: NDStructure<T>): NDStructure<T> = arg.map { value -> multiply(this@times, value) }
+    public operator fun T.times(arg: StructureND<T>): StructureND<T> = arg.map { value -> multiply(this@times, value) }
 
     public companion object
 }
 
 /**
- * Field of [NDStructure].
+ * Field of [StructureND].
  *
  * @param T the type of the element contained in ND structure.
  * @param N the type of ND structure.
  * @param F the type field of structure elements.
  */
-public interface NDField<T, F : Field<T>> : Field<NDStructure<T>>, NDRing<T, F>, ScaleOperations<NDStructure<T>> {
+public interface FieldND<T, F : Field<T>> : Field<StructureND<T>>, RingND<T, F>, ScaleOperations<StructureND<T>> {
     /**
      * Element-wise division.
      *
@@ -206,7 +232,7 @@ public interface NDField<T, F : Field<T>> : Field<NDStructure<T>>, NDRing<T, F>,
      * @param b the divisor.
      * @return the quotient.
      */
-    public override fun divide(a: NDStructure<T>, b: NDStructure<T>): NDStructure<T> =
+    public override fun divide(a: StructureND<T>, b: StructureND<T>): StructureND<T> =
         combine(a, b) { aValue, bValue -> divide(aValue, bValue) }
 
     //TODO move to extensions after KEEP-176
@@ -217,7 +243,7 @@ public interface NDField<T, F : Field<T>> : Field<NDStructure<T>>, NDRing<T, F>,
      * @param arg the divisor.
      * @return the quotient.
      */
-    public operator fun NDStructure<T>.div(arg: T): NDStructure<T> = this.map { value -> divide(arg, value) }
+    public operator fun StructureND<T>.div(arg: T): StructureND<T> = this.map { value -> divide(arg, value) }
 
     /**
      * Divides an element by an ND structure of it.
@@ -226,7 +252,7 @@ public interface NDField<T, F : Field<T>> : Field<NDStructure<T>>, NDRing<T, F>,
      * @param arg the divisor.
      * @return the quotient.
      */
-    public operator fun T.div(arg: NDStructure<T>): NDStructure<T> = arg.map { divide(it, this@div) }
+    public operator fun T.div(arg: StructureND<T>): StructureND<T> = arg.map { divide(it, this@div) }
 
 //    @ThreadLocal
 //    public companion object {

kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/BufferAlgebraND.kt

@@ -6,132 +6,132 @@ import space.kscience.kmath.structures.BufferFactory
 import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
 
-public interface BufferNDAlgebra<T, A : Algebra<T>> : NDAlgebra<T, A> {
+public interface BufferAlgebraND<T, A : Algebra<T>> : AlgebraND<T, A> {
     public val strides: Strides
     public val bufferFactory: BufferFactory<T>
 
-    override fun produce(initializer: A.(IntArray) -> T): NDBuffer<T> = NDBuffer(
+    override fun produce(initializer: A.(IntArray) -> T): BufferND<T> = BufferND(
         strides,
         bufferFactory(strides.linearSize) { offset ->
             elementContext.initializer(strides.index(offset))
         }
     )
 
-    public val NDStructure<T>.buffer: Buffer<T>
+    public val StructureND<T>.buffer: Buffer<T>
         get() = when {
-            !shape.contentEquals(this@BufferNDAlgebra.shape) -> throw ShapeMismatchException(
+            !shape.contentEquals(this@BufferAlgebraND.shape) -> throw ShapeMismatchException(
-                this@BufferNDAlgebra.shape,
+                this@BufferAlgebraND.shape,
                 shape
             )
-            this is NDBuffer && this.strides == this@BufferNDAlgebra.strides -> this.buffer
+            this is BufferND && this.strides == this@BufferAlgebraND.strides -> this.buffer
             else -> bufferFactory(strides.linearSize) { offset -> get(strides.index(offset)) }
         }
 
-    override fun NDStructure<T>.map(transform: A.(T) -> T): NDBuffer<T> {
+    override fun StructureND<T>.map(transform: A.(T) -> T): BufferND<T> {
         val buffer = bufferFactory(strides.linearSize) { offset ->
             elementContext.transform(buffer[offset])
         }
-        return NDBuffer(strides, buffer)
+        return BufferND(strides, buffer)
     }
 
-    override fun NDStructure<T>.mapIndexed(transform: A.(index: IntArray, T) -> T): NDBuffer<T> {
+    override fun StructureND<T>.mapIndexed(transform: A.(index: IntArray, T) -> T): BufferND<T> {
         val buffer = bufferFactory(strides.linearSize) { offset ->
             elementContext.transform(
                 strides.index(offset),
                 buffer[offset]
             )
         }
-        return NDBuffer(strides, buffer)
+        return BufferND(strides, buffer)
     }
 
-    override fun combine(a: NDStructure<T>, b: NDStructure<T>, transform: A.(T, T) -> T): NDBuffer<T> {
+    override fun combine(a: StructureND<T>, b: StructureND<T>, transform: A.(T, T) -> T): BufferND<T> {
         val buffer = bufferFactory(strides.linearSize) { offset ->
             elementContext.transform(a.buffer[offset], b.buffer[offset])
         }
-        return NDBuffer(strides, buffer)
+        return BufferND(strides, buffer)
     }
 }
 
-public open class BufferedNDGroup<T, A : Group<T>>(
+public open class BufferedGroupND<T, A : Group<T>>(
     final override val shape: IntArray,
     final override val elementContext: A,
     final override val bufferFactory: BufferFactory<T>,
-) : NDGroup<T, A>, BufferNDAlgebra<T, A> {
+) : GroupND<T, A>, BufferAlgebraND<T, A> {
     override val strides: Strides = DefaultStrides(shape)
-    override val zero: NDBuffer<T> by lazy { produce { zero } }
+    override val zero: BufferND<T> by lazy { produce { zero } }
-    override fun NDStructure<T>.unaryMinus(): NDStructure<T> = produce { -get(it) }
+    override fun StructureND<T>.unaryMinus(): StructureND<T> = produce { -get(it) }
 }
 
-public open class BufferedNDRing<T, R : Ring<T>>(
+public open class BufferedRingND<T, R : Ring<T>>(
     shape: IntArray,
     elementContext: R,
     bufferFactory: BufferFactory<T>,
-) : BufferedNDGroup<T, R>(shape, elementContext, bufferFactory), NDRing<T, R> {
+) : BufferedGroupND<T, R>(shape, elementContext, bufferFactory), RingND<T, R> {
-    override val one: NDBuffer<T> by lazy { produce { one } }
+    override val one: BufferND<T> by lazy { produce { one } }
 }
 
-public open class BufferedNDField<T, R : Field<T>>(
+public open class BufferedFieldND<T, R : Field<T>>(
     shape: IntArray,
     elementContext: R,
     bufferFactory: BufferFactory<T>,
-) : BufferedNDRing<T, R>(shape, elementContext, bufferFactory), NDField<T, R> {
+) : BufferedRingND<T, R>(shape, elementContext, bufferFactory), FieldND<T, R> {
 
-    override fun scale(a: NDStructure<T>, value: Double): NDStructure<T> = a.map { it * value }
+    override fun scale(a: StructureND<T>, value: Double): StructureND<T> = a.map { it * value }
 }
 
-// space factories
+// group factories
-public fun <T, A : Group<T>> NDAlgebra.Companion.space(
+public fun <T, A : Group<T>> AlgebraND.Companion.group(
     space: A,
     bufferFactory: BufferFactory<T>,
     vararg shape: Int,
-): BufferedNDGroup<T, A> = BufferedNDGroup(shape, space, bufferFactory)
+): BufferedGroupND<T, A> = BufferedGroupND(shape, space, bufferFactory)
 
-public inline fun <T, A : Group<T>, R> A.ndSpace(
+public inline fun <T, A : Group<T>, R> A.ndGroup(
     noinline bufferFactory: BufferFactory<T>,
     vararg shape: Int,
-    action: BufferedNDGroup<T, A>.() -> R,
+    action: BufferedGroupND<T, A>.() -> R,
 ): R {
     contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
-    return NDAlgebra.space(this, bufferFactory, *shape).run(action)
+    return AlgebraND.group(this, bufferFactory, *shape).run(action)
 }
 
 //ring factories
-public fun <T, A : Ring<T>> NDAlgebra.Companion.ring(
+public fun <T, A : Ring<T>> AlgebraND.Companion.ring(
     ring: A,
     bufferFactory: BufferFactory<T>,
     vararg shape: Int,
-): BufferedNDRing<T, A> = BufferedNDRing(shape, ring, bufferFactory)
+): BufferedRingND<T, A> = BufferedRingND(shape, ring, bufferFactory)
 
 public inline fun <T, A : Ring<T>, R> A.ndRing(
     noinline bufferFactory: BufferFactory<T>,
     vararg shape: Int,
-    action: BufferedNDRing<T, A>.() -> R,
+    action: BufferedRingND<T, A>.() -> R,
 ): R {
     contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
-    return NDAlgebra.ring(this, bufferFactory, *shape).run(action)
+    return AlgebraND.ring(this, bufferFactory, *shape).run(action)
 }
 
 //field factories
-public fun <T, A : Field<T>> NDAlgebra.Companion.field(
+public fun <T, A : Field<T>> AlgebraND.Companion.field(
     field: A,
     bufferFactory: BufferFactory<T>,
     vararg shape: Int,
-): BufferedNDField<T, A> = BufferedNDField(shape, field, bufferFactory)
+): BufferedFieldND<T, A> = BufferedFieldND(shape, field, bufferFactory)
 
 @Suppress("UNCHECKED_CAST")
-public inline fun <reified T : Any, A : Field<T>> NDAlgebra.Companion.auto(
+public inline fun <reified T : Any, A : Field<T>> AlgebraND.Companion.auto(
     field: A,
     vararg shape: Int,
-): NDField<T, A> = when (field) {
+): FieldND<T, A> = when (field) {
-    RealField -> RealNDField(shape) as NDField<T, A>
+    DoubleField -> DoubleFieldND(shape) as FieldND<T, A>
-    else -> BufferedNDField(shape, field, Buffer.Companion::auto)
+    else -> BufferedFieldND(shape, field, Buffer.Companion::auto)
 }
 
 public inline fun <T, A : Field<T>, R> A.ndField(
     noinline bufferFactory: BufferFactory<T>,
     vararg shape: Int,
-    action: BufferedNDField<T, A>.() -> R,
+    action: BufferedFieldND<T, A>.() -> R,
 ): R {
     contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
-    return NDAlgebra.field(this, bufferFactory, *shape).run(action)
+    return AlgebraND.field(this, bufferFactory, *shape).run(action)
 }

kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/BufferND.kt

@@ -0,0 +1,48 @@
+package space.kscience.kmath.nd
+
+import space.kscience.kmath.structures.Buffer
+import space.kscience.kmath.structures.BufferFactory
+
+/**
+ * Represents [StructureND] over [Buffer].
+ *
+ * @param T the type of items.
+ * @param strides The strides to access elements of [Buffer] by linear indices.
+ * @param buffer The underlying buffer.
+ */
+public class BufferND<T>(
+    public val strides: Strides,
+    public val buffer: Buffer<T>,
+) : StructureND<T> {
+
+    init {
+        if (strides.linearSize != buffer.size) {
+            error("Expected buffer side of ${strides.linearSize}, but found ${buffer.size}")
+        }
+    }
+
+    override operator fun get(index: IntArray): T = buffer[strides.offset(index)]
+
+    override val shape: IntArray get() = strides.shape
+
+    override fun elements(): Sequence<Pair<IntArray, T>> = strides.indices().map {
+        it to this[it]
+    }
+
+    override fun toString(): String = StructureND.toString(this)
+}
+
+/**
+ * Transform structure to a new structure using provided [BufferFactory] and optimizing if argument is [BufferND]
+ */
+public inline fun <T, reified R : Any> StructureND<T>.mapToBuffer(
+    factory: BufferFactory<R> = Buffer.Companion::auto,
+    crossinline transform: (T) -> R,
+): BufferND<R> {
+    return if (this is BufferND<T>)
+        BufferND(this.strides, factory.invoke(strides.linearSize) { transform(buffer[it]) })
+    else {
+        val strides = DefaultStrides(shape)
+        BufferND(strides, factory.invoke(strides.linearSize) { transform(get(strides.index(it))) })
+    }
+}

kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/DoubleFieldND.kt

@@ -0,0 +1,110 @@
+package space.kscience.kmath.nd
+
+import space.kscience.kmath.misc.UnstableKMathAPI
+import space.kscience.kmath.operations.DoubleField
+import space.kscience.kmath.operations.ExtendedField
+import space.kscience.kmath.operations.NumbersAddOperations
+import space.kscience.kmath.operations.ScaleOperations
+import space.kscience.kmath.structures.DoubleBuffer
+import kotlin.contracts.InvocationKind
+import kotlin.contracts.contract
+
+@OptIn(UnstableKMathAPI::class)
+public class DoubleFieldND(
+    shape: IntArray,
+) : BufferedFieldND<Double, DoubleField>(shape, DoubleField, ::DoubleBuffer),
+    NumbersAddOperations<StructureND<Double>>,
+    ScaleOperations<StructureND<Double>>,
+    ExtendedField<StructureND<Double>> {
+
+    override val zero: BufferND<Double> by lazy { produce { zero } }
+    override val one: BufferND<Double> by lazy { produce { one } }
+
+    override fun number(value: Number): BufferND<Double> {
+        val d = value.toDouble() // minimize conversions
+        return produce { d }
+    }
+
+    override val StructureND<Double>.buffer: DoubleBuffer
+        get() = when {
+            !shape.contentEquals(this@DoubleFieldND.shape) -> throw ShapeMismatchException(
+                this@DoubleFieldND.shape,
+                shape
+            )
+            this is BufferND && this.strides == this@DoubleFieldND.strides -> this.buffer as DoubleBuffer
+            else -> DoubleBuffer(strides.linearSize) { offset -> get(strides.index(offset)) }
+        }
+
+    @Suppress("OVERRIDE_BY_INLINE")
+    override inline fun StructureND<Double>.map(
+        transform: DoubleField.(Double) -> Double,
+    ): BufferND<Double> {
+        val buffer = DoubleBuffer(strides.linearSize) { offset -> DoubleField.transform(buffer.array[offset]) }
+        return BufferND(strides, buffer)
+    }
+
+    @Suppress("OVERRIDE_BY_INLINE")
+    override inline fun produce(initializer: DoubleField.(IntArray) -> Double): BufferND<Double> {
+        val array = DoubleArray(strides.linearSize) { offset ->
+            val index = strides.index(offset)
+            DoubleField.initializer(index)
+        }
+        return BufferND(strides, DoubleBuffer(array))
+    }
+
+    @Suppress("OVERRIDE_BY_INLINE")
+    override inline fun StructureND<Double>.mapIndexed(
+        transform: DoubleField.(index: IntArray, Double) -> Double,
+    ): BufferND<Double> = BufferND(
+        strides,
+        buffer = DoubleBuffer(strides.linearSize) { offset ->
+            DoubleField.transform(
+                strides.index(offset),
+                buffer.array[offset]
+            )
+        })
+
+    @Suppress("OVERRIDE_BY_INLINE")
+    override inline fun combine(
+        a: StructureND<Double>,
+        b: StructureND<Double>,
+        transform: DoubleField.(Double, Double) -> Double,
+    ): BufferND<Double> {
+        val buffer = DoubleBuffer(strides.linearSize) { offset ->
+            DoubleField.transform(a.buffer.array[offset], b.buffer.array[offset])
+        }
+        return BufferND(strides, buffer)
+    }
+
+    override fun scale(a: StructureND<Double>, value: Double): StructureND<Double> = a.map { it * value }
+
+    override fun power(arg: StructureND<Double>, pow: Number): BufferND<Double> = arg.map { power(it, pow) }
+
+    override fun exp(arg: StructureND<Double>): BufferND<Double> = arg.map { exp(it) }
+
+    override fun ln(arg: StructureND<Double>): BufferND<Double> = arg.map { ln(it) }
+
+    override fun sin(arg: StructureND<Double>): BufferND<Double> = arg.map { sin(it) }
+    override fun cos(arg: StructureND<Double>): BufferND<Double> = arg.map { cos(it) }
+    override fun tan(arg: StructureND<Double>): BufferND<Double> = arg.map { tan(it) }
+    override fun asin(arg: StructureND<Double>): BufferND<Double> = arg.map { asin(it) }
+    override fun acos(arg: StructureND<Double>): BufferND<Double> = arg.map { acos(it) }
+    override fun atan(arg: StructureND<Double>): BufferND<Double> = arg.map { atan(it) }
+
+    override fun sinh(arg: StructureND<Double>): BufferND<Double> = arg.map { sinh(it) }
+    override fun cosh(arg: StructureND<Double>): BufferND<Double> = arg.map { cosh(it) }
+    override fun tanh(arg: StructureND<Double>): BufferND<Double> = arg.map { tanh(it) }
+    override fun asinh(arg: StructureND<Double>): BufferND<Double> = arg.map { asinh(it) }
+    override fun acosh(arg: StructureND<Double>): BufferND<Double> = arg.map { acosh(it) }
+    override fun atanh(arg: StructureND<Double>): BufferND<Double> = arg.map { atanh(it) }
+}
+
+public fun AlgebraND.Companion.real(vararg shape: Int): DoubleFieldND = DoubleFieldND(shape)
+
+/**
+ * Produce a context for n-dimensional operations inside this real field
+ */
+public inline fun <R> DoubleField.nd(vararg shape: Int, action: DoubleFieldND.() -> R): R {
+    contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
+    return DoubleFieldND(shape).run(action)
+}

kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/RealNDField.kt

@@ -1,111 +0,0 @@
-package space.kscience.kmath.nd
-
-import space.kscience.kmath.misc.UnstableKMathAPI
-import space.kscience.kmath.operations.ExtendedField
-import space.kscience.kmath.operations.NumbersAddOperations
-import space.kscience.kmath.operations.RealField
-import space.kscience.kmath.operations.ScaleOperations
-import space.kscience.kmath.structures.Buffer
-import space.kscience.kmath.structures.RealBuffer
-import kotlin.contracts.InvocationKind
-import kotlin.contracts.contract
-
-@OptIn(UnstableKMathAPI::class)
-public class RealNDField(
-    shape: IntArray,
-) : BufferedNDField<Double, RealField>(shape, RealField, Buffer.Companion::real),
-    NumbersAddOperations<NDStructure<Double>>,
-    ScaleOperations<NDStructure<Double>>,
-    ExtendedField<NDStructure<Double>> {
-
-    override val zero: NDBuffer<Double> by lazy { produce { zero } }
-    override val one: NDBuffer<Double> by lazy { produce { one } }
-
-    override fun number(value: Number): NDBuffer<Double> {
-        val d = value.toDouble() // minimize conversions
-        return produce { d }
-    }
-
-    override val NDStructure<Double>.buffer: RealBuffer
-        get() = when {
-            !shape.contentEquals(this@RealNDField.shape) -> throw ShapeMismatchException(
-                this@RealNDField.shape,
-                shape
-            )
-            this is NDBuffer && this.strides == this@RealNDField.strides -> this.buffer as RealBuffer
-            else -> RealBuffer(strides.linearSize) { offset -> get(strides.index(offset)) }
-        }
-
-    @Suppress("OVERRIDE_BY_INLINE")
-    override inline fun NDStructure<Double>.map(
-        transform: RealField.(Double) -> Double,
-    ): NDBuffer<Double> {
-        val buffer = RealBuffer(strides.linearSize) { offset -> RealField.transform(buffer.array[offset]) }
-        return NDBuffer(strides, buffer)
-    }
-
-    @Suppress("OVERRIDE_BY_INLINE")
-    override inline fun produce(initializer: RealField.(IntArray) -> Double): NDBuffer<Double> {
-        val array = DoubleArray(strides.linearSize) { offset ->
-            val index = strides.index(offset)
-            RealField.initializer(index)
-        }
-        return NDBuffer(strides, RealBuffer(array))
-    }
-
-    @Suppress("OVERRIDE_BY_INLINE")
-    override inline fun NDStructure<Double>.mapIndexed(
-        transform: RealField.(index: IntArray, Double) -> Double,
-    ): NDBuffer<Double> = NDBuffer(
-        strides,
-        buffer = RealBuffer(strides.linearSize) { offset ->
-            RealField.transform(
-                strides.index(offset),
-                buffer.array[offset]
-            )
-        })
-
-    @Suppress("OVERRIDE_BY_INLINE")
-    override inline fun combine(
-        a: NDStructure<Double>,
-        b: NDStructure<Double>,
-        transform: RealField.(Double, Double) -> Double,
-    ): NDBuffer<Double> {
-        val buffer = RealBuffer(strides.linearSize) { offset ->
-            RealField.transform(a.buffer.array[offset], b.buffer.array[offset])
-        }
-        return NDBuffer(strides, buffer)
-    }
-
-    override fun scale(a: NDStructure<Double>, value: Double): NDStructure<Double> = a.map { it * value }
-
-    override fun power(arg: NDStructure<Double>, pow: Number): NDBuffer<Double> = arg.map { power(it, pow) }
-
-    override fun exp(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { exp(it) }
-
-    override fun ln(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { ln(it) }
-
-    override fun sin(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { sin(it) }
-    override fun cos(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { cos(it) }
-    override fun tan(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { tan(it) }
-    override fun asin(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { asin(it) }
-    override fun acos(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { acos(it) }
-    override fun atan(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { atan(it) }
-
-    override fun sinh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { sinh(it) }
-    override fun cosh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { cosh(it) }
-    override fun tanh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { tanh(it) }
-    override fun asinh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { asinh(it) }
-    override fun acosh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { acosh(it) }
-    override fun atanh(arg: NDStructure<Double>): NDBuffer<Double> = arg.map { atanh(it) }
-}
-
-public fun NDAlgebra.Companion.real(vararg shape: Int): RealNDField = RealNDField(shape)
-
-/**
- * Produce a context for n-dimensional operations inside this real field
- */
-public inline fun <R> RealField.nd(vararg shape: Int, action: RealNDField.() -> R): R {
-    contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
-    return RealNDField(shape).run(action)
-}

kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/ShortRingND.kt

@@ -9,15 +9,15 @@ import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
 
 @OptIn(UnstableKMathAPI::class)
-public class ShortNDRing(
+public class ShortRingND(
     shape: IntArray,
-) : BufferedNDRing<Short, ShortRing>(shape, ShortRing, Buffer.Companion::auto),
+) : BufferedRingND<Short, ShortRing>(shape, ShortRing, Buffer.Companion::auto),
-    NumbersAddOperations<NDStructure<Short>> {
+    NumbersAddOperations<StructureND<Short>> {
 
-    override val zero: NDBuffer<Short> by lazy { produce { zero } }
+    override val zero: BufferND<Short> by lazy { produce { zero } }
-    override val one: NDBuffer<Short> by lazy { produce { one } }
+    override val one: BufferND<Short> by lazy { produce { one } }
 
-    override fun number(value: Number): NDBuffer<Short> {
+    override fun number(value: Number): BufferND<Short> {
         val d = value.toShort() // minimize conversions
         return produce { d }
     }
@@ -26,11 +26,11 @@ public class ShortNDRing(
 /**
  * Fast element production using function inlining.
  */
-public inline fun BufferedNDRing<Short, ShortRing>.produceInline(crossinline initializer: ShortRing.(Int) -> Short): NDBuffer<Short> {
+public inline fun BufferedRingND<Short, ShortRing>.produceInline(crossinline initializer: ShortRing.(Int) -> Short): BufferND<Short> {
-    return NDBuffer(strides, ShortBuffer(ShortArray(strides.linearSize) { offset -> ShortRing.initializer(offset) }))
+    return BufferND(strides, ShortBuffer(ShortArray(strides.linearSize) { offset -> ShortRing.initializer(offset) }))
 }
 
-public inline fun <R> ShortRing.nd(vararg shape: Int, action: ShortNDRing.() -> R): R {
+public inline fun <R> ShortRing.nd(vararg shape: Int, action: ShortRingND.() -> R): R {
     contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
-    return ShortNDRing(shape).run(action)
+    return ShortRingND(shape).run(action)
 }

kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/Structure1D.kt

@@ -6,7 +6,7 @@ import space.kscience.kmath.structures.asSequence
 /**
  * A structure that is guaranteed to be one-dimensional
  */
-public interface Structure1D<T> : NDStructure<T>, Buffer<T> {
+public interface Structure1D<T> : StructureND<T>, Buffer<T> {
     public override val dimension: Int get() = 1
 
     public override operator fun get(index: IntArray): T {
@@ -20,7 +20,7 @@ public interface Structure1D<T> : NDStructure<T>, Buffer<T> {
 /**
  * A 1D wrapper for nd-structure
  */
-private inline class Structure1DWrapper<T>(val structure: NDStructure<T>) : Structure1D<T> {
+private inline class Structure1DWrapper<T>(val structure: StructureND<T>) : Structure1D<T> {
     override val shape: IntArray get() = structure.shape
     override val size: Int get() = structure.shape[0]
 
@@ -43,14 +43,25 @@ private inline class Buffer1DWrapper<T>(val buffer: Buffer<T>) : Structure1D<T>
 }
 
 /**
- * Represent a [NDStructure] as [Structure1D]. Throw error in case of dimension mismatch
+ * Represent a [StructureND] as [Structure1D]. Throw error in case of dimension mismatch
  */
-public fun <T> NDStructure<T>.as1D(): Structure1D<T> = if (shape.size == 1) {
+public fun <T> StructureND<T>.as1D(): Structure1D<T> = this as? Structure1D<T> ?: if (shape.size == 1) {
-    if (this is NDBuffer) Buffer1DWrapper(this.buffer) else Structure1DWrapper(this)
+    when (this) {
-} else
+        is BufferND -> Buffer1DWrapper(this.buffer)
-    error("Can't create 1d-structure from ${shape.size}d-structure")
+        else -> Structure1DWrapper(this)
+    }
+} else error("Can't create 1d-structure from ${shape.size}d-structure")
 
 /**
  * Represent this buffer as 1D structure
  */
 public fun <T> Buffer<T>.asND(): Structure1D<T> = Buffer1DWrapper(this)
+
+/**
+ * Expose inner buffer of this [Structure1D] if possible
+ */
+internal fun <T : Any> Structure1D<T>.unwrap(): Buffer<T> = when {
+    this is Buffer1DWrapper<T> -> buffer
+    this is Structure1DWrapper && structure is BufferND<T> -> structure.buffer
+    else -> this
+}

kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/Structure2D.kt

@@ -1,16 +1,16 @@
 package space.kscience.kmath.nd
 
-import space.kscience.kmath.linear.BufferMatrix
+import space.kscience.kmath.misc.UnstableKMathAPI
-import space.kscience.kmath.linear.RealMatrixContext
 import space.kscience.kmath.structures.Buffer
 import space.kscience.kmath.structures.VirtualBuffer
+import kotlin.reflect.KClass
 
 /**
  * A structure that is guaranteed to be two-dimensional.
  *
  * @param T the type of items.
  */
-public interface Structure2D<T> : NDStructure<T> {
+public interface Structure2D<T> : StructureND<T> {
     /**
      * The number of rows in this structure.
      */
@@ -26,14 +26,14 @@ public interface Structure2D<T> : NDStructure<T> {
     /**
      * The buffer of rows of this structure. It gets elements from the structure dynamically.
      */
-    public val rows: Buffer<Buffer<T>>
+    public val rows: List<Buffer<T>>
-        get() = VirtualBuffer(rowNum) { i -> VirtualBuffer(colNum) { j -> get(i, j) } }
+        get() = List(rowNum) { i -> VirtualBuffer(colNum) { j -> get(i, j) } }
 
     /**
      * The buffer of columns of this structure. It gets elements from the structure dynamically.
      */
-    public val columns: Buffer<Buffer<T>>
+    public val columns: List<Buffer<T>>
-        get() = VirtualBuffer(colNum) { j -> VirtualBuffer(rowNum) { i -> get(i, j) } }
+        get() = List(colNum) { j -> VirtualBuffer(rowNum) { i -> get(i, j) } }
 
     /**
      * Retrieves an element from the structure by two indices.
@@ -54,21 +54,13 @@ public interface Structure2D<T> : NDStructure<T> {
             for (j in 0 until colNum) yield(intArrayOf(i, j) to get(i, j))
     }
 
-    public companion object {
+    public companion object
-        public inline fun real(
-            rows: Int,
-            columns: Int,
-            crossinline init: (i: Int, j: Int) -> Double,
-        ): BufferMatrix<Double> = RealMatrixContext.produce(rows,columns) { i, j ->
-            init(i, j)
-        }
-    }
 }
 
 /**
  * A 2D wrapper for nd-structure
  */
-private inline class Structure2DWrapper<T>(val structure: NDStructure<T>) : Structure2D<T> {
+private inline class Structure2DWrapper<T>(val structure: StructureND<T>) : Structure2D<T> {
     override val shape: IntArray get() = structure.shape
 
     override val rowNum: Int get() = shape[0]
@@ -76,20 +68,23 @@ private inline class Structure2DWrapper<T>(val structure: NDStructure<T>) : Stru
 
     override operator fun get(i: Int, j: Int): T = structure[i, j]
 
+    @UnstableKMathAPI
+    override fun <F : Any> getFeature(type: KClass<F>): F? = structure.getFeature(type)
+
     override fun elements(): Sequence<Pair<IntArray, T>> = structure.elements()
 }
 
 /**
- * Represent a [NDStructure] as [Structure1D]. Throw error in case of dimension mismatch
+ * Represent a [StructureND] as [Structure1D]. Throw error in case of dimension mismatch
  */
-public fun <T> NDStructure<T>.as2D(): Structure2D<T> = if (shape.size == 2)
+public fun <T> StructureND<T>.as2D(): Structure2D<T> = this as? Structure2D<T> ?: when (shape.size) {
-    Structure2DWrapper(this)
+    2 -> Structure2DWrapper(this)
-else
+    else -> error("Can't create 2d-structure from ${shape.size}d-structure")
-    error("Can't create 2d-structure from ${shape.size}d-structure")
+}
 
 /**
- * Alias for [Structure2D] with more familiar name.
+ * Expose inner [StructureND] if possible
- *
- * @param T the type of items in the matrix.
  */
-public typealias Matrix<T> = Structure2D<T>
+internal fun <T> Structure2D<T>.unwrap(): StructureND<T> =
+    if (this is Structure2DWrapper) structure
+    else this

kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/StructureND.kt

@@ -3,8 +3,6 @@ package space.kscience.kmath.nd
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.structures.Buffer
 import space.kscience.kmath.structures.BufferFactory
-import space.kscience.kmath.structures.MutableBuffer
-import space.kscience.kmath.structures.asSequence
 import kotlin.jvm.JvmName
 import kotlin.native.concurrent.ThreadLocal
 import kotlin.reflect.KClass
@@ -14,9 +12,11 @@ import kotlin.reflect.KClass
  * of dimensions and items in an array is defined by its shape, which is a sequence of non-negative integers that
  * specify the sizes of each dimension.
  *
+ * StructureND is in general identity-free. [StructureND.contentEquals] should be used in tests to compare contents.
+ *
  * @param T the type of items.
  */
-public interface NDStructure<T> {
+public interface StructureND<T> {
     /**
      * The shape of structure, i.e. non-empty sequence of non-negative integers that specify sizes of dimensions of
      * this structure.
@@ -43,42 +43,57 @@ public interface NDStructure<T> {
      */
     public fun elements(): Sequence<Pair<IntArray, T>>
 
-    //force override equality and hash code
-    public override fun equals(other: Any?): Boolean
-    public override fun hashCode(): Int
-
     /**
-     * Feature is additional property or hint that does not directly affect the structure, but could in some cases help
+     * Feature is some additional strucure information which allows to access it special properties or hints.
-     * optimize operations and performance. If the feature is not present, null is defined.
+     * If the feature is not present, null is returned.
      */
     @UnstableKMathAPI
-    public fun <T : Any> getFeature(type: KClass<T>): T? = null
+    public fun <F : Any> getFeature(type: KClass<F>): F? = null
 
     public companion object {
         /**
-         * Indicates whether some [NDStructure] is equal to another one.
+         * Indicates whether some [StructureND] is equal to another one.
          */
-        public fun contentEquals(st1: NDStructure<*>, st2: NDStructure<*>): Boolean {
+        public fun <T : Any> contentEquals(st1: StructureND<T>, st2: StructureND<T>): Boolean {
             if (st1 === st2) return true
 
             // fast comparison of buffers if possible
-            if (st1 is NDBuffer && st2 is NDBuffer && st1.strides == st2.strides)
+            if (st1 is BufferND && st2 is BufferND && st1.strides == st2.strides)
-                return st1.buffer.contentEquals(st2.buffer)
+                return Buffer.contentEquals(st1.buffer, st2.buffer)
 
             //element by element comparison if it could not be avoided
             return st1.elements().all { (index, value) -> value == st2[index] }
         }
 
+        /**
+         * Debug output to string
+         */
+        public fun toString(structure: StructureND<*>): String {
+            val bufferRepr: String = when (structure.shape.size) {
+                1 -> (0 until structure.shape[0]).map { structure[it] }
+                    .joinToString(prefix = "[", postfix = "]", separator = ", ")
+                2 -> (0 until structure.shape[0]).joinToString(prefix = "[", postfix = "]", separator = ", ") { i ->
+                    (0 until structure.shape[1]).joinToString(prefix = "[", postfix = "]", separator = ", ") { j ->
+                        structure[i, j].toString()
+                    }
+                }
+                else -> "..."
+            }
+            val className = structure::class.simpleName ?: "StructureND"
+
+            return "$className(shape=${structure.shape.contentToString()}, buffer=$bufferRepr)"
+        }
+
         /**
          * Creates a NDStructure with explicit buffer factory.
          *
          * Strides should be reused if possible.
          */
-        public fun <T> build(
+        public fun <T> buffered(
             strides: Strides,
             bufferFactory: BufferFactory<T> = Buffer.Companion::boxing,
             initializer: (IntArray) -> T,
-        ): NDBuffer<T> = NDBuffer(strides, bufferFactory(strides.linearSize) { i -> initializer(strides.index(i)) })
+        ): BufferND<T> = BufferND(strides, bufferFactory(strides.linearSize) { i -> initializer(strides.index(i)) })
 
         /**
          * Inline create NDStructure with non-boxing buffer implementation if it is possible
@@ -86,37 +101,37 @@ public interface NDStructure<T> {
         public inline fun <reified T : Any> auto(
             strides: Strides,
             crossinline initializer: (IntArray) -> T,
-        ): NDBuffer<T> = NDBuffer(strides, Buffer.auto(strides.linearSize) { i -> initializer(strides.index(i)) })
+        ): BufferND<T> = BufferND(strides, Buffer.auto(strides.linearSize) { i -> initializer(strides.index(i)) })
 
         public inline fun <T : Any> auto(
             type: KClass<T>,
             strides: Strides,
             crossinline initializer: (IntArray) -> T,
-        ): NDBuffer<T> = NDBuffer(strides, Buffer.auto(type, strides.linearSize) { i -> initializer(strides.index(i)) })
+        ): BufferND<T> = BufferND(strides, Buffer.auto(type, strides.linearSize) { i -> initializer(strides.index(i)) })
 
-        public fun <T> build(
+        public fun <T> buffered(
             shape: IntArray,
             bufferFactory: BufferFactory<T> = Buffer.Companion::boxing,
             initializer: (IntArray) -> T,
-        ): NDBuffer<T> = build(DefaultStrides(shape), bufferFactory, initializer)
+        ): BufferND<T> = buffered(DefaultStrides(shape), bufferFactory, initializer)
 
         public inline fun <reified T : Any> auto(
             shape: IntArray,
             crossinline initializer: (IntArray) -> T,
-        ): NDBuffer<T> = auto(DefaultStrides(shape), initializer)
+        ): BufferND<T> = auto(DefaultStrides(shape), initializer)
 
         @JvmName("autoVarArg")
         public inline fun <reified T : Any> auto(
             vararg shape: Int,
             crossinline initializer: (IntArray) -> T,
-        ): NDBuffer<T> =
+        ): BufferND<T> =
             auto(DefaultStrides(shape), initializer)
 
         public inline fun <T : Any> auto(
             type: KClass<T>,
             vararg shape: Int,
             crossinline initializer: (IntArray) -> T,
-        ): NDBuffer<T> = auto(type, DefaultStrides(shape), initializer)
+        ): BufferND<T> = auto(type, DefaultStrides(shape), initializer)
     }
 }
 
@@ -126,15 +141,15 @@ public interface NDStructure<T> {
  * @param index the indices.
  * @return the value.
  */
-public operator fun <T> NDStructure<T>.get(vararg index: Int): T = get(index)
+public operator fun <T> StructureND<T>.get(vararg index: Int): T = get(index)
 
 @UnstableKMathAPI
-public inline fun <reified T : Any> NDStructure<*>.getFeature(): T? = getFeature(T::class)
+public inline fun <reified T : Any> StructureND<*>.getFeature(): T? = getFeature(T::class)
 
 /**
- * Represents mutable [NDStructure].
+ * Represents mutable [StructureND].
  */
-public interface MutableNDStructure<T> : NDStructure<T> {
+public interface MutableStructureND<T> : StructureND<T> {
     /**
      * Inserts an item at the specified indices.
      *
@@ -147,7 +162,7 @@ public interface MutableNDStructure<T> : NDStructure<T> {
 /**
  * Transform a structure element-by element in place.
  */
-public inline fun <T> MutableNDStructure<T>.mapInPlace(action: (IntArray, T) -> T): Unit =
+public inline fun <T> MutableStructureND<T>.mapInPlace(action: (IntArray, T) -> T): Unit =
     elements().forEach { (index, oldValue) -> this[index] = action(index, oldValue) }
 
 /**
@@ -251,97 +266,10 @@ public class DefaultStrides private constructor(override val shape: IntArray) :
     }
 }
 
-/**
+public inline fun <reified T : Any> StructureND<T>.combine(
- * Represents [NDStructure] over [Buffer].
+    struct: StructureND<T>,
- *
- * @param T the type of items.
- * @param strides The strides to access elements of [Buffer] by linear indices.
- * @param buffer The underlying buffer.
- */
-public open class NDBuffer<T>(
-    public val strides: Strides,
-    buffer: Buffer<T>,
-) : NDStructure<T> {
-
-    init {
-        if (strides.linearSize != buffer.size) {
-            error("Expected buffer side of ${strides.linearSize}, but found ${buffer.size}")
-        }
-    }
-
-    public open val buffer: Buffer<T> = buffer
-
-    override operator fun get(index: IntArray): T = buffer[strides.offset(index)]
-
-    override val shape: IntArray get() = strides.shape
-
-    override fun elements(): Sequence<Pair<IntArray, T>> = strides.indices().map {
-        it to this[it]
-    }
-
-    override fun equals(other: Any?): Boolean {
-        return NDStructure.contentEquals(this, other as? NDStructure<*> ?: return false)
-    }
-
-    override fun hashCode(): Int {
-        var result = strides.hashCode()
-        result = 31 * result + buffer.hashCode()
-        return result
-    }
-
-    override fun toString(): String {
-        val bufferRepr: String = when (shape.size) {
-            1 -> buffer.asSequence().joinToString(prefix = "[", postfix = "]", separator = ", ")
-            2 -> (0 until shape[0]).joinToString(prefix = "[", postfix = "]", separator = ", ") { i ->
-                (0 until shape[1]).joinToString(prefix = "[", postfix = "]", separator = ", ") { j ->
-                    val offset = strides.offset(intArrayOf(i, j))
-                    buffer[offset].toString()
-                }
-            }
-            else -> "..."
-        }
-        return "NDBuffer(shape=${shape.contentToString()}, buffer=$bufferRepr)"
-    }
-}
-
-/**
- * Transform structure to a new structure using provided [BufferFactory] and optimizing if argument is [NDBuffer]
- */
-public inline fun <T, reified R : Any> NDStructure<T>.mapToBuffer(
-    factory: BufferFactory<R> = Buffer.Companion::auto,
-    crossinline transform: (T) -> R,
-): NDBuffer<R> {
-    return if (this is NDBuffer<T>)
-        NDBuffer(this.strides, factory.invoke(strides.linearSize) { transform(buffer[it]) })
-    else {
-        val strides = DefaultStrides(shape)
-        NDBuffer(strides, factory.invoke(strides.linearSize) { transform(get(strides.index(it))) })
-    }
-}
-
-/**
- * Mutable ND buffer based on linear [MutableBuffer].
- */
-public class MutableNDBuffer<T>(
-    strides: Strides,
-    buffer: MutableBuffer<T>,
-) : NDBuffer<T>(strides, buffer), MutableNDStructure<T> {
-
-    init {
-        require(strides.linearSize == buffer.size) {
-            "Expected buffer side of ${strides.linearSize}, but found ${buffer.size}"
-        }
-    }
-
-    override val buffer: MutableBuffer<T> = super.buffer as MutableBuffer<T>
-
-    override operator fun set(index: IntArray, value: T): Unit = buffer.set(strides.offset(index), value)
-}
-
-public inline fun <reified T : Any> NDStructure<T>.combine(
-    struct: NDStructure<T>,
     crossinline block: (T, T) -> T,
-): NDStructure<T> {
+): StructureND<T> {
     require(shape.contentEquals(struct.shape)) { "Shape mismatch in structure combination" }
-    return NDStructure.auto(shape) { block(this[it], struct[it]) }
+    return StructureND.auto(shape) { block(this[it], struct[it]) }
 }

kmath-core/src/commonMain/kotlin/space/kscience/kmath/operations/AlgebraElements.kt

@@ -41,7 +41,7 @@ public interface AlgebraElement<T, C : Algebra<T>> {
  */
 @UnstableKMathAPI
 public operator fun <T : AlgebraElement<T, S>, S : NumbersAddOperations<T>> T.minus(b: T): T =
-    context.add(this, context.run { -b})
+    context.add(this, context.run { -b })
 
 /**
  * Adds element to this one.

kmath-core/src/commonMain/kotlin/space/kscience/kmath/operations/BigInt.kt

@@ -1,8 +1,8 @@
 package space.kscience.kmath.operations
 
 import space.kscience.kmath.misc.UnstableKMathAPI
-import space.kscience.kmath.nd.BufferedNDRing
+import space.kscience.kmath.nd.AlgebraND
-import space.kscience.kmath.nd.NDAlgebra
+import space.kscience.kmath.nd.BufferedRingND
 import space.kscience.kmath.operations.BigInt.Companion.BASE
 import space.kscience.kmath.operations.BigInt.Companion.BASE_SIZE
 import space.kscience.kmath.structures.Buffer
@@ -464,5 +464,5 @@ public inline fun Buffer.Companion.bigInt(size: Int, initializer: (Int) -> BigIn
 public inline fun MutableBuffer.Companion.bigInt(size: Int, initializer: (Int) -> BigInt): MutableBuffer<BigInt> =
     boxing(size, initializer)
 
-public fun NDAlgebra.Companion.bigInt(vararg shape: Int): BufferedNDRing<BigInt, BigIntField> =
+public fun AlgebraND.Companion.bigInt(vararg shape: Int): BufferedRingND<BigInt, BigIntField> =
-    BufferedNDRing(shape, BigIntField, Buffer.Companion::bigInt)
+    BufferedRingND(shape, BigIntField, Buffer.Companion::bigInt)

kmath-core/src/commonMain/kotlin/space/kscience/kmath/operations/numbers.kt

@@ -55,7 +55,7 @@ public interface ExtendedField<T> : ExtendedFieldOperations<T>, Field<T>, Numeri
  * A field for [Double] without boxing. Does not produce appropriate field element.
  */
 @Suppress("EXTENSION_SHADOWED_BY_MEMBER", "OVERRIDE_BY_INLINE", "NOTHING_TO_INLINE")
-public object RealField : ExtendedField<Double>, Norm<Double, Double>, ScaleOperations<Double> {
+public object DoubleField : ExtendedField<Double>, Norm<Double, Double>, ScaleOperations<Double> {
     public override val zero: Double = 0.0
     public override val one: Double = 1.0
 

kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/Buffer.kt

@@ -17,7 +17,9 @@ public typealias BufferFactory<T> = (Int, (Int) -> T) -> Buffer<T>
 public typealias MutableBufferFactory<T> = (Int, (Int) -> T) -> MutableBuffer<T>
 
 /**
- * A generic immutable random-access structure for both primitives and objects.
+ * A generic read-only random-access structure for both primitives and objects.
+ *
+ * [Buffer] is in general identity-free. [Buffer.contentEquals] should be used for content equality checks.
  *
  * @param T the type of elements contained in the buffer.
  */
@@ -37,49 +39,46 @@ public interface Buffer<out T> {
      */
     public operator fun iterator(): Iterator<T>
 
-    /**
-     * Checks content equality with another buffer.
-     */
-    public fun contentEquals(other: Buffer<*>): Boolean =
-        asSequence().mapIndexed { index, value -> value == other[index] }.all { it }
-
     public companion object {
+
         /**
-         * Creates a [RealBuffer] with the specified [size], where each element is calculated by calling the specified
+         * Check the element-by-element match of content of two buffers.
-         * [initializer] function.
          */
-        public inline fun real(size: Int, initializer: (Int) -> Double): RealBuffer =
+        public fun <T: Any> contentEquals(first: Buffer<T>, second: Buffer<T>): Boolean{
-            RealBuffer(size) { initializer(it) }
+            if (first.size != second.size) return false
+            for (i in first.indices) {
+                if (first[i] != second[i]) return false
+            }
+            return true
+        }
 
         /**
          * Creates a [ListBuffer] of given type [T] with given [size]. Each element is calculated by calling the
          * specified [initializer] function.
          */
         public inline fun <T> boxing(size: Int, initializer: (Int) -> T): Buffer<T> =
-            ListBuffer(List(size, initializer))
+            List(size, initializer).asBuffer()
-
-        // TODO add resolution based on Annotation or companion resolution
 
         /**
          * Creates a [Buffer] of given [type]. If the type is primitive, specialized buffers are used ([IntBuffer],
-         * [RealBuffer], etc.), [ListBuffer] is returned otherwise.
+         * [DoubleBuffer], etc.), [ListBuffer] is returned otherwise.
          *
          * The [size] is specified, and each element is calculated by calling the specified [initializer] function.
          */
         @Suppress("UNCHECKED_CAST")
         public inline fun <T : Any> auto(type: KClass<T>, size: Int, initializer: (Int) -> T): Buffer<T> =
             when (type) {
-                Double::class -> RealBuffer(size) { initializer(it) as Double } as Buffer<T>
+                Double::class -> MutableBuffer.double(size) { initializer(it) as Double } as Buffer<T>
-                Short::class -> ShortBuffer(size) { initializer(it) as Short } as Buffer<T>
+                Short::class -> MutableBuffer.short(size) { initializer(it) as Short } as Buffer<T>
-                Int::class -> IntBuffer(size) { initializer(it) as Int } as Buffer<T>
+                Int::class -> MutableBuffer.int(size) { initializer(it) as Int } as Buffer<T>
-                Long::class -> LongBuffer(size) { initializer(it) as Long } as Buffer<T>
+                Long::class -> MutableBuffer.long(size) { initializer(it) as Long } as Buffer<T>
-                Float::class -> FloatBuffer(size) { initializer(it) as Float } as Buffer<T>
+                Float::class -> MutableBuffer.float(size) { initializer(it) as Float } as Buffer<T>
                 else -> boxing(size, initializer)
             }
 
         /**
          * Creates a [Buffer] of given type [T]. If the type is primitive, specialized buffers are used ([IntBuffer],
-         * [RealBuffer], etc.), [ListBuffer] is returned otherwise.
+         * [DoubleBuffer], etc.), [ListBuffer] is returned otherwise.
          *
          * The [size] is specified, and each element is calculated by calling the specified [initializer] function.
          */
@@ -89,21 +88,6 @@ public interface Buffer<out T> {
     }
 }
 
-/**
- * Creates a sequence that returns all elements from this [Buffer].
- */
-public fun <T> Buffer<T>.asSequence(): Sequence<T> = Sequence(::iterator)
-
-/**
- * Creates an iterable that returns all elements from this [Buffer].
- */
-public fun <T> Buffer<T>.asIterable(): Iterable<T> = Iterable(::iterator)
-
-/**
- * Converts this [Buffer] to a new [List]
- */
-public fun <T> Buffer<T>.toList(): List<T> = asSequence().toList()
-
 /**
  * Returns an [IntRange] of the valid indices for this [Buffer].
  */
@@ -126,6 +110,44 @@ public interface MutableBuffer<T> : Buffer<T> {
     public fun copy(): MutableBuffer<T>
 
     public companion object {
+
+        /**
+         * Creates a [DoubleBuffer] with the specified [size], where each element is calculated by calling the specified
+         * [initializer] function.
+         */
+        public inline fun double(size: Int, initializer: (Int) -> Double): DoubleBuffer =
+            DoubleBuffer(size, initializer)
+
+        /**
+         * Creates a [ShortBuffer] with the specified [size], where each element is calculated by calling the specified
+         * [initializer] function.
+         */
+        public inline fun short(size: Int, initializer: (Int) -> Short): ShortBuffer =
+            ShortBuffer(size, initializer)
+
+        /**
+         * Creates a [IntBuffer] with the specified [size], where each element is calculated by calling the specified
+         * [initializer] function.
+         */
+        public inline fun int(size: Int, initializer: (Int) -> Int): IntBuffer =
+            IntBuffer(size, initializer)
+
+        /**
+         * Creates a [LongBuffer] with the specified [size], where each element is calculated by calling the specified
+         * [initializer] function.
+         */
+        public inline fun long(size: Int, initializer: (Int) -> Long): LongBuffer =
+            LongBuffer(size, initializer)
+
+
+        /**
+         * Creates a [FloatBuffer] with the specified [size], where each element is calculated by calling the specified
+         * [initializer] function.
+         */
+        public inline fun float(size: Int, initializer: (Int) -> Float): FloatBuffer =
+            FloatBuffer(size, initializer)
+
+
         /**
          * Create a boxing mutable buffer of given type
          */
@@ -134,37 +156,30 @@ public interface MutableBuffer<T> : Buffer<T> {
 
         /**
          * Creates a [MutableBuffer] of given [type]. If the type is primitive, specialized buffers are used
-         * ([IntBuffer], [RealBuffer], etc.), [ListBuffer] is returned otherwise.
+         * ([IntBuffer], [DoubleBuffer], etc.), [ListBuffer] is returned otherwise.
          *
          * The [size] is specified, and each element is calculated by calling the specified [initializer] function.
          */
         @Suppress("UNCHECKED_CAST")
         public inline fun <T : Any> auto(type: KClass<out T>, size: Int, initializer: (Int) -> T): MutableBuffer<T> =
             when (type) {
-                Double::class -> RealBuffer(size) { initializer(it) as Double } as MutableBuffer<T>
+                Double::class -> double(size) { initializer(it) as Double } as MutableBuffer<T>
-                Short::class -> ShortBuffer(size) { initializer(it) as Short } as MutableBuffer<T>
+                Short::class -> short(size) { initializer(it) as Short } as MutableBuffer<T>
-                Int::class -> IntBuffer(size) { initializer(it) as Int } as MutableBuffer<T>
+                Int::class -> int(size) { initializer(it) as Int } as MutableBuffer<T>
-                Float::class -> FloatBuffer(size) { initializer(it) as Float } as MutableBuffer<T>
+                Float::class -> float(size) { initializer(it) as Float } as MutableBuffer<T>
-                Long::class -> LongBuffer(size) { initializer(it) as Long } as MutableBuffer<T>
+                Long::class -> long(size) { initializer(it) as Long } as MutableBuffer<T>
                 else -> boxing(size, initializer)
             }
 
         /**
          * Creates a [MutableBuffer] of given type [T]. If the type is primitive, specialized buffers are used
-         * ([IntBuffer], [RealBuffer], etc.), [ListBuffer] is returned otherwise.
+         * ([IntBuffer], [DoubleBuffer], etc.), [ListBuffer] is returned otherwise.
          *
          * The [size] is specified, and each element is calculated by calling the specified [initializer] function.
          */
         @Suppress("UNCHECKED_CAST")
         public inline fun <reified T : Any> auto(size: Int, initializer: (Int) -> T): MutableBuffer<T> =
             auto(T::class, size, initializer)
-
-        /**
-         * Creates a [RealBuffer] with the specified [size], where each element is calculated by calling the specified
-         * [initializer] function.
-         */
-        public inline fun real(size: Int, initializer: (Int) -> Double): RealBuffer =
-            RealBuffer(size) { initializer(it) }
     }
 }
 
@@ -187,15 +202,6 @@ public inline class ListBuffer<T>(public val list: List<T>) : Buffer<T> {
  */
 public fun <T> List<T>.asBuffer(): ListBuffer<T> = ListBuffer(this)
 
-/**
- * Creates a new [ListBuffer] with the specified [size], where each element is calculated by calling the specified
- * [init] function.
- *
- * The function [init] is called for each array element sequentially starting from the first one.
- * It should return the value for an array element given its index.
- */
-public inline fun <T> ListBuffer(size: Int, init: (Int) -> T): ListBuffer<T> = List(size, init).asBuffer()
-
 /**
  * [MutableBuffer] implementation over [MutableList].
  *
@@ -216,16 +222,20 @@ public inline class MutableListBuffer<T>(public val list: MutableList<T>) : Muta
     override fun copy(): MutableBuffer<T> = MutableListBuffer(ArrayList(list))
 }
 
+/**
+ * Returns an [ListBuffer] that wraps the original list.
+ */
+public fun <T> MutableList<T>.asMutableBuffer(): MutableListBuffer<T> = MutableListBuffer(this)
+
 /**
  * [MutableBuffer] implementation over [Array].
  *
  * @param T the type of elements contained in the buffer.
  * @property array The underlying array.
  */
-public class ArrayBuffer<T>(private val array: Array<T>) : MutableBuffer<T> {
+public class ArrayBuffer<T>(internal val array: Array<T>) : MutableBuffer<T> {
     // Can't inline because array is invariant
-    override val size: Int
+    override val size: Int get() = array.size
-        get() = array.size
 
     override operator fun get(index: Int): T = array[index]
 
@@ -243,16 +253,6 @@ public class ArrayBuffer<T>(private val array: Array<T>) : MutableBuffer<T> {
  */
 public fun <T> Array<T>.asBuffer(): ArrayBuffer<T> = ArrayBuffer(this)
 
-/**
- * Creates a new [ArrayBuffer] with the specified [size], where each element is calculated by calling the specified
- * [init] function.
- *
- * The function [init] is called for each array element sequentially starting from the first one.
- * It should return the value for an array element given its index.
- */
-public inline fun <reified T> ArrayBuffer(size: Int, init: (Int) -> T): ArrayBuffer<T> =
-    Array(size) { i -> init(i) }.asBuffer()
-
 /**
  * Immutable wrapper for [MutableBuffer].
  *
@@ -280,27 +280,9 @@ public class VirtualBuffer<T>(override val size: Int, private val generator: (In
     }
 
     override operator fun iterator(): Iterator<T> = (0 until size).asSequence().map(generator).iterator()
-
-    override fun contentEquals(other: Buffer<*>): Boolean {
-        return if (other is VirtualBuffer) {
-            this.size == other.size && this.generator == other.generator
-        } else {
-            super.contentEquals(other)
-        }
-    }
 }
 
 /**
  * Convert this buffer to read-only buffer.
  */
 public fun <T> Buffer<T>.asReadOnly(): Buffer<T> = if (this is MutableBuffer) ReadOnlyBuffer(this) else this
-
-/**
- * Typealias for buffer transformations.
- */
-public typealias BufferTransform<T, R> = (Buffer<T>) -> Buffer<R>
-
-/**
- * Typealias for buffer transformations with suspend function.
- */
-public typealias SuspendBufferTransform<T, R> = suspend (Buffer<T>) -> Buffer<R>

kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/BufferAccessor2D.kt

@@ -1,8 +1,8 @@
 package space.kscience.kmath.structures
 
 import space.kscience.kmath.nd.DefaultStrides
-import space.kscience.kmath.nd.NDStructure
 import space.kscience.kmath.nd.Structure2D
+import space.kscience.kmath.nd.StructureND
 import space.kscience.kmath.nd.as2D
 
 /**
@@ -13,10 +13,10 @@ internal class BufferAccessor2D<T : Any>(
     public val colNum: Int,
     val factory: MutableBufferFactory<T>,
 ) {
-    public operator fun Buffer<T>.get(i: Int, j: Int): T = get(i + colNum * j)
+    public operator fun Buffer<T>.get(i: Int, j: Int): T = get(i * colNum + j)
 
     public operator fun MutableBuffer<T>.set(i: Int, j: Int, value: T) {
-        set(i + colNum * j, value)
+        set(i * colNum + j, value)
     }
 
     public inline fun create(crossinline init: (i: Int, j: Int) -> T): MutableBuffer<T> =
@@ -25,7 +25,7 @@ internal class BufferAccessor2D<T : Any>(
     public fun create(mat: Structure2D<T>): MutableBuffer<T> = create { i, j -> mat[i, j] }
 
     //TODO optimize wrapper
-    public fun MutableBuffer<T>.collect(): Structure2D<T> = NDStructure.build(
+    public fun MutableBuffer<T>.collect(): Structure2D<T> = StructureND.buffered(
         DefaultStrides(intArrayOf(rowNum, colNum)),
         factory
     ) { (i, j) ->

kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/DoubleBuffer.kt

@@ -0,0 +1,56 @@
+package space.kscience.kmath.structures
+
+/**
+ * Specialized [MutableBuffer] implementation over [DoubleArray].
+ *
+ * @property array the underlying array.
+ */
+@Suppress("OVERRIDE_BY_INLINE")
+public inline class DoubleBuffer(public val array: DoubleArray) : MutableBuffer<Double> {
+    override val size: Int get() = array.size
+
+    override operator fun get(index: Int): Double = array[index]
+
+    override operator fun set(index: Int, value: Double) {
+        array[index] = value
+    }
+
+    override operator fun iterator(): DoubleIterator = array.iterator()
+
+    override fun copy(): DoubleBuffer = DoubleBuffer(array.copyOf())
+}
+
+/**
+ * Creates a new [DoubleBuffer] with the specified [size], where each element is calculated by calling the specified
+ * [init] function.
+ *
+ * The function [init] is called for each array element sequentially starting from the first one.
+ * It should return the value for an buffer element given its index.
+ */
+public inline fun DoubleBuffer(size: Int, init: (Int) -> Double): DoubleBuffer = DoubleBuffer(DoubleArray(size) { init(it) })
+
+/**
+ * Returns a new [DoubleBuffer] of given elements.
+ */
+public fun DoubleBuffer(vararg doubles: Double): DoubleBuffer = DoubleBuffer(doubles)
+
+/**
+ * Simplified [DoubleBuffer] to array comparison
+ */
+public fun DoubleBuffer.contentEquals(vararg doubles: Double): Boolean = array.contentEquals(doubles)
+
+/**
+ * Returns a new [DoubleArray] containing all of the elements of this [Buffer].
+ */
+public fun Buffer<Double>.toDoubleArray(): DoubleArray = when (this) {
+    is DoubleBuffer -> array.copyOf()
+    else -> DoubleArray(size, ::get)
+}
+
+/**
+ * Returns [DoubleBuffer] over this array.
+ *
+ * @receiver the array.
+ * @return the new buffer.
+ */
+public fun DoubleArray.asBuffer(): DoubleBuffer = DoubleBuffer(this)

kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/DoubleBufferField.kt

@@ -0,0 +1,272 @@
+package space.kscience.kmath.structures
+
+import space.kscience.kmath.operations.ExtendedField
+import space.kscience.kmath.operations.ExtendedFieldOperations
+import kotlin.math.*
+
+/**
+ * [ExtendedFieldOperations] over [DoubleBuffer].
+ */
+public object DoubleBufferFieldOperations : ExtendedFieldOperations<Buffer<Double>> {
+    override fun Buffer<Double>.unaryMinus(): DoubleBuffer = if (this is DoubleBuffer) {
+        DoubleBuffer(size) { -array[it] }
+    } else {
+        DoubleBuffer(size) { -get(it) }
+    }
+
+    public override fun add(a: Buffer<Double>, b: Buffer<Double>): DoubleBuffer {
+        require(b.size == a.size) {
+            "The size of the first buffer ${a.size} should be the same as for second one: ${b.size} "
+        }
+
+        return if (a is DoubleBuffer && b is DoubleBuffer) {
+            val aArray = a.array
+            val bArray = b.array
+            DoubleBuffer(DoubleArray(a.size) { aArray[it] + bArray[it] })
+        } else DoubleBuffer(DoubleArray(a.size) { a[it] + b[it] })
+    }
+//
+//    public override fun multiply(a: Buffer<Double>, k: Number): RealBuffer {
+//        val kValue = k.toDouble()
+//
+//        return if (a is RealBuffer) {
+//            val aArray = a.array
+//            RealBuffer(DoubleArray(a.size) { aArray[it] * kValue })
+//        } else RealBuffer(DoubleArray(a.size) { a[it] * kValue })
+//    }
+//
+//    public override fun divide(a: Buffer<Double>, k: Number): RealBuffer {
+//        val kValue = k.toDouble()
+//
+//        return if (a is RealBuffer) {
+//            val aArray = a.array
+//            RealBuffer(DoubleArray(a.size) { aArray[it] / kValue })
+//        } else RealBuffer(DoubleArray(a.size) { a[it] / kValue })
+//    }
+
+    public override fun multiply(a: Buffer<Double>, b: Buffer<Double>): DoubleBuffer {
+        require(b.size == a.size) {
+            "The size of the first buffer ${a.size} should be the same as for second one: ${b.size} "
+        }
+
+        return if (a is DoubleBuffer && b is DoubleBuffer) {
+            val aArray = a.array
+            val bArray = b.array
+            DoubleBuffer(DoubleArray(a.size) { aArray[it] * bArray[it] })
+        } else
+            DoubleBuffer(DoubleArray(a.size) { a[it] * b[it] })
+    }
+
+    public override fun divide(a: Buffer<Double>, b: Buffer<Double>): DoubleBuffer {
+        require(b.size == a.size) {
+            "The size of the first buffer ${a.size} should be the same as for second one: ${b.size} "
+        }
+
+        return if (a is DoubleBuffer && b is DoubleBuffer) {
+            val aArray = a.array
+            val bArray = b.array
+            DoubleBuffer(DoubleArray(a.size) { aArray[it] / bArray[it] })
+        } else DoubleBuffer(DoubleArray(a.size) { a[it] / b[it] })
+    }
+
+    public override fun sin(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { sin(array[it]) })
+    } else DoubleBuffer(DoubleArray(arg.size) { sin(arg[it]) })
+
+    public override fun cos(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { cos(array[it]) })
+    } else DoubleBuffer(DoubleArray(arg.size) { cos(arg[it]) })
+
+    public override fun tan(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { tan(array[it]) })
+    } else DoubleBuffer(DoubleArray(arg.size) { tan(arg[it]) })
+
+    public override fun asin(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { asin(array[it]) })
+    } else
+        DoubleBuffer(DoubleArray(arg.size) { asin(arg[it]) })
+
+    public override fun acos(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { acos(array[it]) })
+    } else
+        DoubleBuffer(DoubleArray(arg.size) { acos(arg[it]) })
+
+    public override fun atan(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { atan(array[it]) })
+    } else
+        DoubleBuffer(DoubleArray(arg.size) { atan(arg[it]) })
+
+    public override fun sinh(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { sinh(array[it]) })
+    } else
+        DoubleBuffer(DoubleArray(arg.size) { sinh(arg[it]) })
+
+    public override fun cosh(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { cosh(array[it]) })
+    } else
+        DoubleBuffer(DoubleArray(arg.size) { cosh(arg[it]) })
+
+    public override fun tanh(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { tanh(array[it]) })
+    } else
+        DoubleBuffer(DoubleArray(arg.size) { tanh(arg[it]) })
+
+    public override fun asinh(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { asinh(array[it]) })
+    } else
+        DoubleBuffer(DoubleArray(arg.size) { asinh(arg[it]) })
+
+    public override fun acosh(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { acosh(array[it]) })
+    } else
+        DoubleBuffer(DoubleArray(arg.size) { acosh(arg[it]) })
+
+    public override fun atanh(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { atanh(array[it]) })
+    } else
+        DoubleBuffer(DoubleArray(arg.size) { atanh(arg[it]) })
+
+    public override fun power(arg: Buffer<Double>, pow: Number): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { array[it].pow(pow.toDouble()) })
+    } else
+        DoubleBuffer(DoubleArray(arg.size) { arg[it].pow(pow.toDouble()) })
+
+    public override fun exp(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { exp(array[it]) })
+    } else DoubleBuffer(DoubleArray(arg.size) { exp(arg[it]) })
+
+    public override fun ln(arg: Buffer<Double>): DoubleBuffer = if (arg is DoubleBuffer) {
+        val array = arg.array
+        DoubleBuffer(DoubleArray(arg.size) { ln(array[it]) })
+    } else
+        DoubleBuffer(DoubleArray(arg.size) { ln(arg[it]) })
+}
+
+/**
+ * [ExtendedField] over [DoubleBuffer].
+ *
+ * @property size the size of buffers to operate on.
+ */
+public class DoubleBufferField(public val size: Int) : ExtendedField<Buffer<Double>> {
+    public override val zero: Buffer<Double> by lazy { DoubleBuffer(size) { 0.0 } }
+    public override val one: Buffer<Double> by lazy { DoubleBuffer(size) { 1.0 } }
+
+    override fun number(value: Number): Buffer<Double> = DoubleBuffer(size) { value.toDouble() }
+
+    override fun Buffer<Double>.unaryMinus(): Buffer<Double> = DoubleBufferFieldOperations.run {
+        -this@unaryMinus
+    }
+
+    public override fun add(a: Buffer<Double>, b: Buffer<Double>): DoubleBuffer {
+        require(a.size == size) { "The buffer size ${a.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.add(a, b)
+    }
+
+    public override fun scale(a: Buffer<Double>, value: Double): DoubleBuffer {
+        require(a.size == size) { "The buffer size ${a.size} does not match context size $size" }
+
+        return if (a is DoubleBuffer) {
+            val aArray = a.array
+            DoubleBuffer(DoubleArray(a.size) { aArray[it] * value })
+        } else DoubleBuffer(DoubleArray(a.size) { a[it] * value })
+    }
+
+    public override fun multiply(a: Buffer<Double>, b: Buffer<Double>): DoubleBuffer {
+        require(a.size == size) { "The buffer size ${a.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.multiply(a, b)
+    }
+
+    public override fun divide(a: Buffer<Double>, b: Buffer<Double>): DoubleBuffer {
+        require(a.size == size) { "The buffer size ${a.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.divide(a, b)
+    }
+
+    public override fun sin(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.sin(arg)
+    }
+
+    public override fun cos(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.cos(arg)
+    }
+
+    public override fun tan(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.tan(arg)
+    }
+
+    public override fun asin(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.asin(arg)
+    }
+
+    public override fun acos(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.acos(arg)
+    }
+
+    public override fun atan(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.atan(arg)
+    }
+
+    public override fun sinh(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.sinh(arg)
+    }
+
+    public override fun cosh(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.cosh(arg)
+    }
+
+    public override fun tanh(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.tanh(arg)
+    }
+
+    public override fun asinh(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.asinh(arg)
+    }
+
+    public override fun acosh(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.acosh(arg)
+    }
+
+    public override fun atanh(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.atanh(arg)
+    }
+
+    public override fun power(arg: Buffer<Double>, pow: Number): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.power(arg, pow)
+    }
+
+    public override fun exp(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.exp(arg)
+    }
+
+    public override fun ln(arg: Buffer<Double>): DoubleBuffer {
+        require(arg.size == size) { "The buffer size ${arg.size} does not match context size $size" }
+        return DoubleBufferFieldOperations.ln(arg)
+    }
+}

kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/FlaggedBuffer.kt

@@ -48,7 +48,7 @@ public fun FlaggedBuffer<*>.isMissing(index: Int): Boolean = hasFlag(index, Valu
 /**
  * A real buffer which supports flags for each value like NaN or Missing
  */
-public class FlaggedRealBuffer(public val values: DoubleArray, public val flags: ByteArray) : FlaggedBuffer<Double?>,
+public class FlaggedDoubleBuffer(public val values: DoubleArray, public val flags: ByteArray) : FlaggedBuffer<Double?>,
     Buffer<Double?> {
     init {
         require(values.size == flags.size) { "Values and flags must have the same dimensions" }
@@ -65,7 +65,7 @@ public class FlaggedRealBuffer(public val values: DoubleArray, public val flags:
     }.iterator()
 }
 
-public inline fun FlaggedRealBuffer.forEachValid(block: (Double) -> Unit) {
+public inline fun FlaggedDoubleBuffer.forEachValid(block: (Double) -> Unit) {
     indices
         .asSequence()
         .filter(::isValid)

kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/FloatBuffer.kt

@@ -36,10 +36,12 @@ public inline fun FloatBuffer(size: Int, init: (Int) -> Float): FloatBuffer = Fl
 public fun FloatBuffer(vararg floats: Float): FloatBuffer = FloatBuffer(floats)
 
 /**
- * Returns a [FloatArray] containing all of the elements of this [MutableBuffer].
+ * Returns a new [FloatArray] containing all of the elements of this [Buffer].
  */
-public val MutableBuffer<out Float>.array: FloatArray
+public fun Buffer<Float>.toFloatArray(): FloatArray = when (this) {
-    get() = (if (this is FloatBuffer) array else FloatArray(size) { get(it) })
+    is FloatBuffer -> array.copyOf()
+    else -> FloatArray(size, ::get)
+}
 
 /**
  * Returns [FloatBuffer] over this array.

kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/IntBuffer.kt

@@ -35,10 +35,12 @@ public inline fun IntBuffer(size: Int, init: (Int) -> Int): IntBuffer = IntBuffe
 public fun IntBuffer(vararg ints: Int): IntBuffer = IntBuffer(ints)
 
 /**
- * Returns a [IntArray] containing all of the elements of this [MutableBuffer].
+ * Returns a new [IntArray] containing all of the elements of this [Buffer].
  */
-public val MutableBuffer<out Int>.array: IntArray
+public fun Buffer<Int>.toIntArray(): IntArray = when (this) {
-    get() = (if (this is IntBuffer) array else IntArray(size) { get(it) })
+    is IntBuffer -> array.copyOf()
+    else -> IntArray(size, ::get)
+}
 
 /**
  * Returns [IntBuffer] over this array.