kmath-for-real refactoring

2020-11-29 13:32:20 +03:00 · 2020-11-29 13:32:20 +03:00 · 5b653f10d7
commit 5b653f10d7
parent c21e761a76
19 changed files with 310 additions and 94 deletions
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -27,6 +27,7 @@
 - Full autodiff refactoring based on `Symbol`
 - `kmath-prob` renamed to `kmath-stat`
 - Grid generators moved to `kmath-for-real`
+- Use `Point<Double>` instead of specialized type in `kmath-for-real`

 ### Deprecated

--- a/README.md
+++ b/README.md
@ -132,9 +132,17 @@ submit a feature request if you want something to be implemented first.
 <hr/>

 * ### [kmath-for-real](kmath-for-real)
-> 
+> Extension module that should be used to achieve numpy-like behavior. 
+All operations are specialized to work with `Double` numbers without declaring algebraic contexts.
+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
+> - [RealMatrix](kmath-for-real/src/commonMain/kotlin/kscience/kmath/real/RealMatrix.kt) : Numpy-like operations for 2d real structures
+> - [grids](kmath-for-real/src/commonMain/kotlin/kscience/kmath/structures/grids.kt) : Uniform grid generators
+
 <hr/>

 * ### [kmath-functions](kmath-functions)
@ -155,6 +163,12 @@ submit a feature request if you want something to be implemented first.
 > **Maturity**: EXPERIMENTAL
 <hr/>

+* ### [kmath-kotlingrad](kmath-kotlingrad)
+> 
+>
+> **Maturity**: EXPERIMENTAL
+<hr/>
+
 * ### [kmath-memory](kmath-memory)
 > 
 >
@ -167,7 +181,7 @@ submit a feature request if you want something to be implemented first.
 > **Maturity**: EXPERIMENTAL
 >
 > **Features:**
-> - [nd4jarraystrucure](kmath-nd4j/src/commonMain/kotlin/kscience/kmath/operations/Algebra.kt) : NDStructure wrapper for INDArray
+> - [nd4jarraystructure](kmath-nd4j/src/commonMain/kotlin/kscience/kmath/operations/Algebra.kt) : NDStructure wrapper for INDArray
 > - [nd4jarrayrings](kmath-nd4j/src/commonMain/kotlin/kscience/kmath/structures/NDStructure.kt) : 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

@ -211,20 +225,12 @@ Release artifacts are accessible from bintray with following configuration (see

 ```kotlin
 repositories {
-    jcenter()
-    maven("https://clojars.org/repo")
-    maven("https://dl.bintray.com/egor-bogomolov/astminer/")
-    maven("https://dl.bintray.com/hotkeytlt/maven")
-    maven("https://dl.bintray.com/kotlin/kotlin-eap")
-    maven("https://dl.bintray.com/kotlin/kotlinx")
    maven("https://dl.bintray.com/mipt-npm/kscience")
-    maven("https://jitpack.io")
-    mavenCentral()
 }

 dependencies {
-    api("kscience.kmath:kmath-core:0.2.0-dev-3")
-    // api("kscience.kmath:kmath-core-jvm:0.2.0-dev-3") for jvm-specific version
+    api("kscience.kmath:kmath-core:0.2.0-dev-4")
+    // api("kscience.kmath:kmath-core-jvm:0.2.0-dev-4") for jvm-specific version
 }
 ```

@ -236,15 +242,7 @@ Development builds are uploaded to the separate repository:

 ```kotlin
 repositories {
-    jcenter()
-    maven("https://clojars.org/repo")
-    maven("https://dl.bintray.com/egor-bogomolov/astminer/")
-    maven("https://dl.bintray.com/hotkeytlt/maven")
-    maven("https://dl.bintray.com/kotlin/kotlin-eap")
-    maven("https://dl.bintray.com/kotlin/kotlinx")
    maven("https://dl.bintray.com/mipt-npm/dev")
-    maven("https://jitpack.io")
-    mavenCentral()
 }
 ```

--- a/examples/build.gradle.kts
+++ b/examples/build.gradle.kts
@ -35,6 +35,9 @@ dependencies {
    implementation(project(":kmath-dimensions"))
    implementation(project(":kmath-ejml"))
    implementation(project(":kmath-nd4j"))
+
+    implementation(project(":kmath-for-real"))
+
    implementation("org.deeplearning4j:deeplearning4j-core:1.0.0-beta7")
    implementation("org.nd4j:nd4j-native:1.0.0-beta7")

@ -51,7 +54,11 @@ dependencies {
    implementation("org.jetbrains.kotlinx:kotlinx-io:0.2.0-npm-dev-11")
    implementation("org.jetbrains.kotlinx:kotlinx.benchmark.runtime:0.2.0-dev-20")
    implementation("org.slf4j:slf4j-simple:1.7.30")
-    "benchmarksImplementation"("org.jetbrains.kotlinx:kotlinx.benchmark.runtime-jvm:0.2.0-dev-8")
+
+    // plotting
+    implementation("kscience.plotlykt:plotlykt-server:0.3.1-dev")
+
+    "benchmarksImplementation"("org.jetbrains.kotlinx:kotlinx.benchmark.runtime-jvm:0.2.0-dev-20")
    "benchmarksImplementation"(sourceSets.main.get().output + sourceSets.main.get().runtimeClasspath)
 }

--- a/examples/src/main/kotlin/kscience/kmath/commons/fit/fitWithAutoDiff.kt
+++ b/examples/src/main/kotlin/kscience/kmath/commons/fit/fitWithAutoDiff.kt
@ -0,0 +1,101 @@
+package kscience.kmath.commons.fit
+
+import kotlinx.html.br
+import kotlinx.html.h3
+import kscience.kmath.commons.optimization.chiSquared
+import kscience.kmath.commons.optimization.minimize
+import kscience.kmath.expressions.symbol
+import kscience.kmath.real.RealVector
+import kscience.kmath.real.map
+import kscience.kmath.real.step
+import kscience.kmath.stat.*
+import kscience.kmath.structures.asIterable
+import kscience.kmath.structures.toList
+import kscience.plotly.*
+import kscience.plotly.models.ScatterMode
+import kscience.plotly.models.TraceValues
+import kotlin.math.pow
+import kotlin.math.sqrt
+
+//Forward declaration of symbols that will be used in expressions.
+// This declaration is required for
+private val a by symbol
+private val b by symbol
+private val c by symbol
+
+/**
+ * Shortcut to use buffers in plotly
+ */
+operator fun TraceValues.invoke(vector: RealVector) {
+    numbers = vector.asIterable()
+}
+
+/**
+ * Least squares fie with auto-differentiation. Uses `kmath-commons` and `kmath-for-real` modules.
+ */
+fun main() {
+
+    //A generator for a normally distributed values
+    val generator = Distribution.normal()
+
+    //A chain/flow of random values with the given seed
+    val chain = generator.sample(RandomGenerator.default(112667))
+
+
+    //Create a uniformly distributed x values like numpy.arrange
+    val x = 1.0..100.0 step 1.0
+
+
+    //Perform an operation on each x value (much more effective, than numpy)
+    val y = x.map {
+        val value = it.pow(2) + it + 1
+        value + chain.nextDouble() * sqrt(value)
+    }
+    // this will also work, but less effective:
+    // val y = x.pow(2)+ x + 1 + chain.nextDouble()
+
+    // create same errors for all xs
+    val yErr = y.map { sqrt(it) }//RealVector.same(x.size, sigma)
+
+    // compute differentiable chi^2 sum for given model ax^2 + bx + c
+    val chi2 = Fitting.chiSquared(x, y, yErr) { x1 ->
+        //bind variables to autodiff context
+        val a = bind(a)
+        val b = bind(b)
+        //Include default value for c if it is not provided as a parameter
+        val c = bindOrNull(c) ?: one
+        a * x1.pow(2) + b * x1 + c
+    }
+
+    //minimize the chi^2 in given starting point. Derivatives are not required, they are already included.
+    val result: OptimizationResult<Double> = chi2.minimize(a to 1.5, b to 0.9, c to 1.0)
+
+    val page = Plotly.page {
+        plot {
+            scatter {
+                mode = ScatterMode.markers
+                x(x)
+                y(y)
+                error_y {
+                    array = yErr.toList()
+                }
+                name = "data"
+            }
+            scatter {
+                mode = ScatterMode.lines
+                x(x)
+                y(x.map { result.point[a]!! * it.pow(2) + result.point[b]!! * it + 1 })
+                name = "fit"
+            }
+        }
+        br()
+        h3{
+            +"Fit result: $result"
+        }
+        h3{
+            +"Chi2/dof = ${result.value / (x.size - 3)}"
+        }
+    }
+
+    page.makeFile()
+}
--- a/examples/src/main/kotlin/kscience/kmath/commons/prob/DistributionBenchmark.kt
+++ b/examples/src/main/kotlin/kscience/kmath/commons/prob/DistributionBenchmark.kt
--- a/examples/src/main/kotlin/kscience/kmath/commons/prob/DistributionDemo.kt
+++ b/examples/src/main/kotlin/kscience/kmath/commons/prob/DistributionDemo.kt
@ -1,14 +1,17 @@
-package kscience.kmath.commons.prob
+package kscience.kmath.stat

 import kotlinx.coroutines.runBlocking
 import kscience.kmath.chains.Chain
 import kscience.kmath.chains.collectWithState
-import kscience.kmath.stat.Distribution
-import kscience.kmath.stat.RandomGenerator
-import kscience.kmath.stat.normal

+/**
+ * The state of distribution averager
+ */
 private data class AveragingChainState(var num: Int = 0, var value: Double = 0.0)

+/**
+ * Averaging
+ */
 private fun Chain<Double>.mean(): Chain<Double> = collectWithState(AveragingChainState(), { it.copy() }) { chain ->
    val next = chain.next()
    num++
--- a/kmath-core/README.md
+++ b/kmath-core/README.md
@ -12,7 +12,7 @@ The core features of KMath:

 > #### Artifact:
 >
-> This module artifact: `kscience.kmath:kmath-core:0.2.0-dev-3`.
+> This module artifact: `kscience.kmath:kmath-core:0.2.0-dev-4`.
 >
 > 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)
 >
@ -30,7 +30,7 @@ The core features of KMath:
 > }
 > 
 > dependencies {
->     implementation 'kscience.kmath:kmath-core:0.2.0-dev-3'
+>     implementation 'kscience.kmath:kmath-core:0.2.0-dev-4'
 > }
 > ```
 > **Gradle Kotlin DSL:**
@ -44,6 +44,6 @@ The core features of KMath:
 > }
 > 
 > dependencies {
->     implementation("kscience.kmath:kmath-core:0.2.0-dev-3")
+>     implementation("kscience.kmath:kmath-core:0.2.0-dev-4")
 > }
 > ```
--- a/kmath-core/src/commonMain/kotlin/kscience/kmath/linear/VectorSpace.kt
+++ b/kmath-core/src/commonMain/kotlin/kscience/kmath/linear/VectorSpace.kt
@ -15,7 +15,7 @@ public interface VectorSpace<T : Any, S : Space<T>> : Space<Point<T>> {
    public val space: S
    override val zero: Point<T> get() = produce { space.zero }

-    public fun produce(initializer: (Int) -> T): Point<T>
+    public fun produce(initializer: S.(Int) -> T): Point<T>

    /**
     * Produce a space-element of this vector space for expressions
@ -48,7 +48,7 @@ public interface VectorSpace<T : Any, S : Space<T>> : Space<Point<T>> {
        public fun <T : Any, S : Space<T>> buffered(
            size: Int,
            space: S,
-            bufferFactory: BufferFactory<T> = Buffer.Companion::boxing
+            bufferFactory: BufferFactory<T> = Buffer.Companion::boxing,
        ): BufferVectorSpace<T, S> = BufferVectorSpace(size, space, bufferFactory)

        /**
@ -63,8 +63,8 @@ public interface VectorSpace<T : Any, S : Space<T>> : Space<Point<T>> {
 public class BufferVectorSpace<T : Any, S : Space<T>>(
    override val size: Int,
    override val space: S,
-    public val bufferFactory: BufferFactory<T>
+    public val bufferFactory: BufferFactory<T>,
 ) : VectorSpace<T, S> {
-    override fun produce(initializer: (Int) -> T): Buffer<T> = bufferFactory(size, initializer)
+    override fun produce(initializer: S.(Int) -> T): Buffer<T> = bufferFactory(size) { space.initializer(it) }
    //override fun produceElement(initializer: (Int) -> T): Vector<T, S> = BufferVector(this, produce(initializer))
 }
--- a/kmath-core/src/commonMain/kotlin/kscience/kmath/misc/annotations.kt
+++ b/kmath-core/src/commonMain/kotlin/kscience/kmath/misc/annotations.kt
@ -0,0 +1,4 @@
+package kscience.kmath.misc
+
+@RequiresOptIn("This API is unstable and could change in future", RequiresOptIn.Level.WARNING)
+public annotation class UnstableKMathAPI
--- a/kmath-core/src/commonMain/kotlin/kscience/kmath/structures/Buffers.kt
+++ b/kmath-core/src/commonMain/kotlin/kscience/kmath/structures/Buffers.kt
@ -102,6 +102,11 @@ public fun <T> Buffer<T>.asSequence(): Sequence<T> = Sequence(::iterator)
 */
 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].
 */
--- a/kmath-coroutines/src/commonMain/kotlin/kscience/kmath/chains/Chain.kt
+++ b/kmath-coroutines/src/commonMain/kotlin/kscience/kmath/chains/Chain.kt
@ -47,7 +47,7 @@ public fun <T> Iterator<T>.asChain(): Chain<T> = SimpleChain { next() }
 public fun <T> Sequence<T>.asChain(): Chain<T> = iterator().asChain()

 /**
- * A simple chain of independent tokens
+ * A simple chain of independent tokens. [fork] returns the same chain.
 */
 public class SimpleChain<out R>(private val gen: suspend () -> R) : Chain<R> {
    public override suspend fun next(): R = gen()
--- a/kmath-for-real/README.md
+++ b/kmath-for-real/README.md
@ -0,0 +1,44 @@
+# Real number specialization module (`kmath-for-real`)
+
+ - [RealVector](src/commonMain/kotlin/kscience/kmath/real/RealVector.kt) : Numpy-like operations for Buffers/Points
+ - [RealMatrix](src/commonMain/kotlin/kscience/kmath/real/RealMatrix.kt) : Numpy-like operations for 2d real structures
+ - [grids](src/commonMain/kotlin/kscience/kmath/structures/grids.kt) : Uniform grid generators
+
+
+> #### Artifact:
+>
+> This module artifact: `kscience.kmath:kmath-for-real:0.2.0-dev-4`.
+>
+> Bintray release version:        [ ![Download](https://api.bintray.com/packages/mipt-npm/kscience/kmath-for-real/images/download.svg) ](https://bintray.com/mipt-npm/kscience/kmath-for-real/_latestVersion)
+>
+> Bintray development version:    [ ![Download](https://api.bintray.com/packages/mipt-npm/dev/kmath-for-real/images/download.svg) ](https://bintray.com/mipt-npm/dev/kmath-for-real/_latestVersion)
+>
+> **Gradle:**
+>
+> ```gradle
+> repositories {
+>     maven { url "https://dl.bintray.com/kotlin/kotlin-eap" }
+>     maven { url 'https://dl.bintray.com/mipt-npm/kscience' }
+>     maven { url 'https://dl.bintray.com/mipt-npm/dev' }
+>     maven { url 'https://dl.bintray.com/hotkeytlt/maven' }
+
+> }
+> 
+> dependencies {
+>     implementation 'kscience.kmath:kmath-for-real:0.2.0-dev-4'
+> }
+> ```
+> **Gradle Kotlin DSL:**
+>
+> ```kotlin
+> repositories {
+>     maven("https://dl.bintray.com/kotlin/kotlin-eap")
+>     maven("https://dl.bintray.com/mipt-npm/kscience")
+>     maven("https://dl.bintray.com/mipt-npm/dev")
+>     maven("https://dl.bintray.com/hotkeytlt/maven")
+> }
+> 
+> dependencies {
+>     implementation("kscience.kmath:kmath-for-real:0.2.0-dev-4")
+> }
+> ```
--- a/kmath-for-real/build.gradle.kts
+++ b/kmath-for-real/build.gradle.kts
@ -7,3 +7,31 @@ kotlin.sourceSets.commonMain {
        api(project(":kmath-core"))
    }
 }
+
+readme {
+    description = """
+        Extension module that should be used to achieve numpy-like behavior. 
+        All operations are specialized to work with `Double` numbers without declaring algebraic contexts.
+        One can still use generic algebras though.
+        """.trimIndent()
+    maturity = ru.mipt.npm.gradle.Maturity.EXPERIMENTAL
+    propertyByTemplate("artifact", rootProject.file("docs/templates/ARTIFACT-TEMPLATE.md"))
+
+    feature(
+        id = "RealVector",
+        description = "Numpy-like operations for Buffers/Points",
+        ref = "src/commonMain/kotlin/kscience/kmath/real/RealVector.kt"
+    )
+
+    feature(
+        id = "RealMatrix",
+        description = "Numpy-like operations for 2d real structures",
+        ref = "src/commonMain/kotlin/kscience/kmath/real/RealMatrix.kt"
+    )
+
+    feature(
+        id = "grids",
+        description = "Uniform grid generators",
+        ref = "src/commonMain/kotlin/kscience/kmath/structures/grids.kt"
+    )
+}
--- a/kmath-for-real/docs/README-TEMPLATE.md
+++ b/kmath-for-real/docs/README-TEMPLATE.md
@ -0,0 +1,5 @@
+# Real number specialization module (`kmath-for-real`)
+
+${features}
+
+${artifact}
--- a/kmath-for-real/src/commonMain/kotlin/kscience/kmath/real/RealMatrix.kt
+++ b/kmath-for-real/src/commonMain/kotlin/kscience/kmath/real/RealMatrix.kt
@ -3,6 +3,7 @@ package kscience.kmath.real
 import kscience.kmath.linear.MatrixContext
 import kscience.kmath.linear.RealMatrixContext.elementContext
 import kscience.kmath.linear.VirtualMatrix
+import kscience.kmath.misc.UnstableKMathAPI
 import kscience.kmath.operations.invoke
 import kscience.kmath.operations.sum
 import kscience.kmath.structures.Buffer
@ -36,7 +37,7 @@ public fun Sequence<DoubleArray>.toMatrix(): RealMatrix = toList().let {
    MatrixContext.real.produce(it.size, it[0].size) { row, col -> it[row][col] }
 }

-public fun Matrix<Double>.repeatStackVertical(n: Int): RealMatrix =
+public fun RealMatrix.repeatStackVertical(n: Int): RealMatrix =
    VirtualMatrix(rowNum * n, colNum) { row, col ->
        get(if (row == 0) 0 else row % rowNum, col)
    }
@ -45,43 +46,43 @@ public fun Matrix<Double>.repeatStackVertical(n: Int): RealMatrix =
 *  Operations for matrix and real number
 */

-public operator fun Matrix<Double>.times(double: Double): RealMatrix =
+public operator fun RealMatrix.times(double: Double): RealMatrix =
    MatrixContext.real.produce(rowNum, colNum) { row, col ->
        this[row, col] * double
    }

-public operator fun Matrix<Double>.plus(double: Double): RealMatrix =
+public operator fun RealMatrix.plus(double: Double): RealMatrix =
    MatrixContext.real.produce(rowNum, colNum) { row, col ->
        this[row, col] + double
    }

-public operator fun Matrix<Double>.minus(double: Double): RealMatrix =
+public operator fun RealMatrix.minus(double: Double): RealMatrix =
    MatrixContext.real.produce(rowNum, colNum) { row, col ->
        this[row, col] - double
    }

-public operator fun Matrix<Double>.div(double: Double): RealMatrix =
+public operator fun RealMatrix.div(double: Double): RealMatrix =
    MatrixContext.real.produce(rowNum, colNum) { row, col ->
        this[row, col] / double
    }

-public operator fun Double.times(matrix: Matrix<Double>): RealMatrix =
+public operator fun Double.times(matrix: RealMatrix): RealMatrix =
    MatrixContext.real.produce(matrix.rowNum, matrix.colNum) { row, col ->
        this * matrix[row, col]
    }

-public operator fun Double.plus(matrix: Matrix<Double>): RealMatrix =
+public operator fun Double.plus(matrix: RealMatrix): RealMatrix =
    MatrixContext.real.produce(matrix.rowNum, matrix.colNum) { row, col ->
        this + matrix[row, col]
    }

-public operator fun Double.minus(matrix: Matrix<Double>): RealMatrix =
+public operator fun Double.minus(matrix: RealMatrix): RealMatrix =
    MatrixContext.real.produce(matrix.rowNum, matrix.colNum) { row, col ->
        this - matrix[row, col]
    }

 // TODO: does this operation make sense? Should it be 'this/matrix[row, col]'?
-//operator fun Double.div(matrix: Matrix<Double>) = MatrixContext.real.produce(matrix.rowNum, matrix.colNum) {
+//operator fun Double.div(matrix: RealMatrix) = MatrixContext.real.produce(matrix.rowNum, matrix.colNum) {
 //    row, col -> matrix[row, col] / this
 //}

@ -89,11 +90,11 @@ public operator fun Double.minus(matrix: Matrix<Double>): RealMatrix =
 *  Per-element (!) square and power operations
 */

-public fun Matrix<Double>.square(): RealMatrix = MatrixContext.real.produce(rowNum, colNum) { row, col ->
+public fun RealMatrix.square(): RealMatrix = MatrixContext.real.produce(rowNum, colNum) { row, col ->
    this[row, col].pow(2)
 }

-public fun Matrix<Double>.pow(n: Int): RealMatrix = MatrixContext.real.produce(rowNum, colNum) { i, j ->
+public fun RealMatrix.pow(n: Int): RealMatrix = MatrixContext.real.produce(rowNum, colNum) { i, j ->
    this[i, j].pow(n)
 }

@ -101,20 +102,21 @@ public fun Matrix<Double>.pow(n: Int): RealMatrix = MatrixContext.real.produce(r
 * Operations on two matrices (per-element!)
 */

-public operator fun Matrix<Double>.times(other: Matrix<Double>): RealMatrix =
+@UnstableKMathAPI
+public operator fun RealMatrix.times(other: RealMatrix): RealMatrix =
    MatrixContext.real.produce(rowNum, colNum) { row, col -> this[row, col] * other[row, col] }

-public operator fun Matrix<Double>.plus(other: Matrix<Double>): RealMatrix =
+public operator fun RealMatrix.plus(other: RealMatrix): RealMatrix =
    MatrixContext.real.add(this, other)

-public operator fun Matrix<Double>.minus(other: Matrix<Double>): RealMatrix =
+public operator fun RealMatrix.minus(other: RealMatrix): RealMatrix =
    MatrixContext.real.produce(rowNum, colNum) { row, col -> this[row, col] - other[row, col] }

 /*
 *  Operations on columns
 */

-public inline fun Matrix<Double>.appendColumn(crossinline mapper: (Buffer<Double>) -> Double): Matrix<Double> =
+public inline fun RealMatrix.appendColumn(crossinline mapper: (Buffer<Double>) -> Double): RealMatrix =
    MatrixContext.real.produce(rowNum, colNum + 1) { row, col ->
        if (col < colNum)
            this[row, col]
@ -122,28 +124,28 @@ public inline fun Matrix<Double>.appendColumn(crossinline mapper: (Buffer<Double
            mapper(rows[row])
    }

-public fun Matrix<Double>.extractColumns(columnRange: IntRange): RealMatrix =
+public fun RealMatrix.extractColumns(columnRange: IntRange): RealMatrix =
    MatrixContext.real.produce(rowNum, columnRange.count()) { row, col ->
        this[row, columnRange.first + col]
    }

-public fun Matrix<Double>.extractColumn(columnIndex: Int): RealMatrix =
+public fun RealMatrix.extractColumn(columnIndex: Int): RealMatrix =
    extractColumns(columnIndex..columnIndex)

-public fun Matrix<Double>.sumByColumn(): RealBuffer = RealBuffer(colNum) { j ->
+public fun RealMatrix.sumByColumn(): RealBuffer = RealBuffer(colNum) { j ->
    val column = columns[j]
    elementContext { sum(column.asIterable()) }
 }

-public fun Matrix<Double>.minByColumn(): RealBuffer = RealBuffer(colNum) { j ->
+public fun RealMatrix.minByColumn(): RealBuffer = RealBuffer(colNum) { j ->
    columns[j].asIterable().minOrNull() ?: error("Cannot produce min on empty column")
 }

-public fun Matrix<Double>.maxByColumn(): RealBuffer = RealBuffer(colNum) { j ->
+public fun RealMatrix.maxByColumn(): RealBuffer = RealBuffer(colNum) { j ->
    columns[j].asIterable().maxOrNull() ?: error("Cannot produce min on empty column")
 }

-public fun Matrix<Double>.averageByColumn(): RealBuffer = RealBuffer(colNum) { j ->
+public fun RealMatrix.averageByColumn(): RealBuffer = RealBuffer(colNum) { j ->
    columns[j].asIterable().average()
 }

@ -151,7 +153,7 @@ public fun Matrix<Double>.averageByColumn(): RealBuffer = RealBuffer(colNum) { j
 * Operations processing all elements
 */

-public fun Matrix<Double>.sum(): Double = elements().map { (_, value) -> value }.sum()
-public fun Matrix<Double>.min(): Double? = elements().map { (_, value) -> value }.minOrNull()
-public fun Matrix<Double>.max(): Double? = elements().map { (_, value) -> value }.maxOrNull()
-public fun Matrix<Double>.average(): Double = elements().map { (_, value) -> value }.average()
+public fun RealMatrix.sum(): Double = elements().map { (_, value) -> value }.sum()
+public fun RealMatrix.min(): Double? = elements().map { (_, value) -> value }.minOrNull()
+public fun RealMatrix.max(): Double? = elements().map { (_, value) -> value }.maxOrNull()
+public fun RealMatrix.average(): Double = elements().map { (_, value) -> value }.average()
--- a/kmath-for-real/src/commonMain/kotlin/kscience/kmath/real/RealVector.kt
+++ b/kmath-for-real/src/commonMain/kotlin/kscience/kmath/real/RealVector.kt
@ -1,47 +1,63 @@
 package kscience.kmath.real

-import kscience.kmath.linear.BufferVectorSpace
 import kscience.kmath.linear.Point
-import kscience.kmath.linear.VectorSpace
 import kscience.kmath.operations.Norm
-import kscience.kmath.operations.RealField
-import kscience.kmath.operations.SpaceElement
 import kscience.kmath.structures.Buffer
-import kscience.kmath.structures.RealBuffer
-import kscience.kmath.structures.asBuffer
 import kscience.kmath.structures.asIterable
+import kotlin.math.pow
 import kotlin.math.sqrt

-public typealias RealPoint = Point<Double>
-
-public fun RealPoint.asVector(): RealVector = RealVector(this)
-public fun DoubleArray.asVector(): RealVector = asBuffer().asVector()
-public fun List<Double>.asVector(): RealVector = asBuffer().asVector()
+public typealias RealVector = Point<Double>

 public object VectorL2Norm : Norm<Point<out Number>, Double> {
    override fun norm(arg: Point<out Number>): Double = sqrt(arg.asIterable().sumByDouble(Number::toDouble))
 }

-public inline class RealVector(private val point: Point<Double>) :
-    SpaceElement<RealPoint, RealVector, VectorSpace<Double, RealField>>, RealPoint {
-    public override val size: Int get() = point.size
-    public override val context: VectorSpace<Double, RealField> get() = space(point.size)
+/**
+ * Fill the vector of given [size] with given [value]
+ */
+public fun Buffer.Companion.same(size: Int, value: Number): RealVector = real(size) { value.toDouble() }

-    public override fun unwrap(): RealPoint = point
-    public override fun RealPoint.wrap(): RealVector = RealVector(this)
-    public override operator fun get(index: Int): Double = point[index]
-    public override operator fun iterator(): Iterator<Double> = point.iterator()
+// Transformation methods

-    public companion object {
-        private val spaceCache: MutableMap<Int, BufferVectorSpace<Double, RealField>> = hashMapOf()
+public inline fun RealVector.map(transform: (Double) -> Double): RealVector =
+    Buffer.real(size) { transform(get(it)) }

-        public inline operator fun invoke(dim: Int, initializer: (Int) -> Double): RealVector =
-            RealVector(RealBuffer(dim, initializer))
+public inline fun RealVector.mapIndexed(transform: (index: Int, value: Double) -> Double): RealVector =
+    Buffer.real(size) { transform(it, get(it)) }

-        public operator fun invoke(vararg values: Double): RealVector = values.asVector()
+public fun RealVector.pow(p: Double): RealVector = map { it.pow(p) }

-        public fun space(dim: Int): BufferVectorSpace<Double, RealField> = spaceCache.getOrPut(dim) {
-            BufferVectorSpace(dim, RealField) { size, init -> Buffer.real(size, init) }
-        }
-    }
-}
+public fun RealVector.pow(p: Int): RealVector = map { it.pow(p) }
+
+public fun exp(vector: RealVector): RealVector = vector.map { kotlin.math.exp(it) }
+
+public operator fun RealVector.plus(other: RealVector): RealVector =
+    mapIndexed { index, value -> value + other[index] }
+
+public operator fun RealVector.plus(number: Number): RealVector = map { it + number.toDouble() }
+
+public operator fun Number.plus(vector: RealVector): RealVector = vector + this
+
+public operator fun RealVector.unaryMinus(): Buffer<Double> = map { -it }
+
+public operator fun RealVector.minus(other: RealVector): RealVector =
+    mapIndexed { index, value -> value - other[index] }
+
+public operator fun RealVector.minus(number: Number): RealVector = map { it - number.toDouble() }
+
+public operator fun Number.minus(vector: RealVector): RealVector = vector.map { toDouble() - it }
+
+public operator fun RealVector.times(other: RealVector): RealVector =
+    mapIndexed { index, value -> value * other[index] }
+
+public operator fun RealVector.times(number: Number): RealVector = map { it * number.toDouble() }
+
+public operator fun Number.times(vector: RealVector): RealVector = vector * this
+
+public operator fun RealVector.div(other: RealVector): RealVector =
+    mapIndexed { index, value -> value / other[index] }
+
+public operator fun RealVector.div(number: Number): RealVector = map { it / number.toDouble() }
+
+public operator fun Number.div(vector: RealVector): RealVector = vector.map { toDouble() / it }
--- a/kmath-for-real/src/commonMain/kotlin/kscience/kmath/real/grids.kt
+++ b/kmath-for-real/src/commonMain/kotlin/kscience/kmath/real/grids.kt
@ -1,6 +1,5 @@
 package kscience.kmath.real

-import kscience.kmath.linear.Point
 import kscience.kmath.structures.asBuffer
 import kotlin.math.abs

@ -34,7 +33,7 @@ public fun ClosedFloatingPointRange<Double>.toSequenceWithStep(step: Double): Se
    }
 }

-public infix fun ClosedFloatingPointRange<Double>.step(step: Double): Point<Double> =
+public infix fun ClosedFloatingPointRange<Double>.step(step: Double): RealVector =
    toSequenceWithStep(step).toList().asBuffer()

 /**
--- a/kmath-nd4j/README.md
+++ b/kmath-nd4j/README.md
@ -2,14 +2,14 @@

 This subproject implements the following features:

- - [nd4jarraystrucure](src/commonMain/kotlin/kscience/kmath/operations/Algebra.kt) : NDStructure wrapper for INDArray
+ - [nd4jarraystructure](src/commonMain/kotlin/kscience/kmath/operations/Algebra.kt) : NDStructure wrapper for INDArray
 - [nd4jarrayrings](src/commonMain/kotlin/kscience/kmath/structures/NDStructure.kt) : Rings over Nd4jArrayStructure of Int and Long
 - [nd4jarrayfields](src/commonMain/kotlin/kscience/kmath/structures/Buffers.kt) : Fields over Nd4jArrayStructure of Float and Double


 > #### Artifact:
 >
-> This module artifact: `kscience.kmath:kmath-nd4j:0.2.0-dev-3`.
+> This module artifact: `kscience.kmath:kmath-nd4j:0.2.0-dev-4`.
 >
 > Bintray release version:        [ ![Download](https://api.bintray.com/packages/mipt-npm/kscience/kmath-nd4j/images/download.svg) ](https://bintray.com/mipt-npm/kscience/kmath-nd4j/_latestVersion)
 >
@ -27,7 +27,7 @@ This subproject implements the following features:
 > }
 > 
 > dependencies {
->     implementation 'kscience.kmath:kmath-nd4j:0.2.0-dev-3'
+>     implementation 'kscience.kmath:kmath-nd4j:0.2.0-dev-4'
 > }
 > ```
 > **Gradle Kotlin DSL:**
@ -41,7 +41,7 @@ This subproject implements the following features:
 > }
 > 
 > dependencies {
->     implementation("kscience.kmath:kmath-nd4j:0.2.0-dev-3")
+>     implementation("kscience.kmath:kmath-nd4j:0.2.0-dev-4")
 > }
 > ```

--- a/kmath-stat/src/jvmMain/kotlin/kscience/kmath/stat/distributions.kt
+++ b/kmath-stat/src/jvmMain/kotlin/kscience/kmath/stat/distributions.kt
@ -51,7 +51,7 @@ private fun normalSampler(method: NormalSamplerMethod, provider: UniformRandomPr

 public fun Distribution.Companion.normal(
    method: NormalSamplerMethod = NormalSamplerMethod.Ziggurat
-): Distribution<Double> = object : ContinuousSamplerDistribution() {
+): ContinuousSamplerDistribution = object : ContinuousSamplerDistribution() {
    override fun buildCMSampler(generator: RandomGenerator): ContinuousSampler {
        val provider = generator.asUniformRandomProvider()
        return normalSampler(method, provider)
@ -60,6 +60,9 @@ public fun Distribution.Companion.normal(
    override fun probability(arg: Double): Double = exp(-arg.pow(2) / 2) / sqrt(PI * 2)
 }

+/**
+ * A univariate normal distribution with given [mean] and [sigma]. [method] defines commons-rng generation method
+ */
 public fun Distribution.Companion.normal(
    mean: Double,
    sigma: Double,