Basic series

build.gradle.kts

@@ -2,6 +2,7 @@ import java.net.URL
 
 plugins {
     id("ru.mipt.npm.gradle.project")
+    id("org.jetbrains.kotlinx.kover") version "0.4.1"
     kotlin("jupyter.api") apply false
 }
 

examples/src/main/kotlin/space/kscience/kmath/series/analyzeDif.kt

@@ -0,0 +1,37 @@
+package space.kscience.kmath.series
+
+
+import net.jafama.StrictFastMath.abs
+import space.kscience.kmath.operations.algebra
+import space.kscience.kmath.operations.bufferAlgebra
+import space.kscience.kmath.operations.invoke
+import space.kscience.kmath.operations.toList
+import space.kscience.kmath.structures.Buffer
+import space.kscience.plotly.Plotly
+import space.kscience.plotly.makeFile
+import space.kscience.plotly.scatter
+import kotlin.math.PI
+import kotlin.math.max
+
+fun main() = Double.algebra.bufferAlgebra.seriesAlgebra(0..100).invoke {
+    fun Buffer<Double>.plot() {
+        val ls = labels
+        Plotly.plot {
+            scatter {
+                x.numbers = ls
+                y.numbers = toList()
+            }
+        }.makeFile()
+    }
+
+
+    val s1 = series(100) { sin(2 * PI * it / 100) }
+    val s2 = series(100) { 1.0 }
+
+    (s1 - s2).plot()
+
+    // Kolmogorov-Smirnov test statistic
+    val kst = (s1 - s2).fold(0.0) { sup, arg -> max(sup, abs(arg))}
+
+
+}

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

@@ -36,7 +36,7 @@ class StreamDoubleFieldND(override val shape: IntArray) : FieldND<Double, Double
                 this@StreamDoubleFieldND.shape,
                 shape
             )
-            this is BufferND && this.indices == this@StreamDoubleFieldND.strides -> this.buffer as DoubleBuffer
+            this is BufferND && this.shapeIndices == this@StreamDoubleFieldND.strides -> this.buffer as DoubleBuffer
             else -> DoubleBuffer(strides.linearSize) { offset -> get(strides.index(offset)) }
         }
 

kmath-core/build.gradle.kts

@@ -2,7 +2,6 @@ plugins {
     kotlin("multiplatform")
     id("ru.mipt.npm.gradle.common")
     id("ru.mipt.npm.gradle.native")
-//    id("com.xcporter.metaview") version "0.0.5"
 }
 
 kotlin.sourceSets {
@@ -13,12 +12,6 @@ kotlin.sourceSets {
     }
 }
 
-//generateUml {
-//    classTree {
-//
-//    }
-//}
-
 readme {
     description = "Core classes, algebra definitions, basic linear algebra"
     maturity = ru.mipt.npm.gradle.Maturity.DEVELOPMENT

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

@@ -7,7 +7,6 @@ package space.kscience.kmath.domains
 import space.kscience.kmath.linear.Point
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.structures.Buffer
-import space.kscience.kmath.structures.indices
 
 /**
  *

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

@@ -8,7 +8,6 @@ package space.kscience.kmath.expressions
 import space.kscience.kmath.operations.ExtendedField
 import space.kscience.kmath.operations.asIterable
 import space.kscience.kmath.structures.Buffer
-import space.kscience.kmath.structures.indices
 import kotlin.jvm.JvmName
 
 /**

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

@@ -13,11 +13,10 @@ import space.kscience.kmath.operations.*
 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, out A : Ring<T>>(
-    private val bufferAlgebra: BufferAlgebra<T, A>
+    private val bufferAlgebra: BufferAlgebra<T, A>,
 ) : LinearSpace<T, A> {
     override val elementAlgebra: A get() = bufferAlgebra.elementAlgebra
 

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

@@ -26,7 +26,7 @@ public fun Shape(shapeFirst: Int, vararg shapeRest: Int): Shape = intArrayOf(sha
 public interface WithShape {
     public val shape: Shape
 
-    public val indices: ShapeIndexer get() = DefaultStrides(shape)
+    public val shapeIndices: ShapeIndices get() = DefaultStrides(shape)
 }
 
 /**

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

@@ -13,7 +13,7 @@ import space.kscience.kmath.operations.*
 import space.kscience.kmath.structures.BufferFactory
 
 public interface BufferAlgebraND<T, out A : Algebra<T>> : AlgebraND<T, A> {
-    public val indexerBuilder: (IntArray) -> ShapeIndexer
+    public val indexerBuilder: (IntArray) -> ShapeIndices
     public val bufferAlgebra: BufferAlgebra<T, A>
     override val elementAlgebra: A get() = bufferAlgebra.elementAlgebra
 
@@ -47,7 +47,7 @@ public interface BufferAlgebraND<T, out A : Algebra<T>> : AlgebraND<T, A> {
         zipInline(left.toBufferND(), right.toBufferND(), transform)
 
     public companion object {
-        public val defaultIndexerBuilder: (IntArray) -> ShapeIndexer = DefaultStrides.Companion::invoke
+        public val defaultIndexerBuilder: (IntArray) -> ShapeIndices = DefaultStrides.Companion::invoke
     }
 }
 
@@ -55,7 +55,7 @@ public inline fun <T, A : Algebra<T>> BufferAlgebraND<T, A>.mapInline(
     arg: BufferND<T>,
     crossinline transform: A.(T) -> T,
 ): BufferND<T> {
-    val indexes = arg.indices
+    val indexes = arg.shapeIndices
     val buffer = arg.buffer
     return BufferND(
         indexes,
@@ -69,7 +69,7 @@ internal inline fun <T, A : Algebra<T>> BufferAlgebraND<T, A>.mapIndexedInline(
     arg: BufferND<T>,
     crossinline transform: A.(index: IntArray, arg: T) -> T,
 ): BufferND<T> {
-    val indexes = arg.indices
+    val indexes = arg.shapeIndices
     val buffer = arg.buffer
     return BufferND(
         indexes,
@@ -84,8 +84,8 @@ internal inline fun <T, A : Algebra<T>> BufferAlgebraND<T, A>.zipInline(
     r: BufferND<T>,
     crossinline block: A.(l: T, r: T) -> T,
 ): BufferND<T> {
-    require(l.indices == r.indices) { "Zip requires the same shapes, but found ${l.shape} on the left and ${r.shape} on the right" }
+    require(l.shapeIndices == r.shapeIndices) { "Zip requires the same shapes, but found ${l.shape} on the left and ${r.shape} on the right" }
-    val indexes = l.indices
+    val indexes = l.shapeIndices
     val lbuffer = l.buffer
     val rbuffer = r.buffer
     return BufferND(
@@ -99,25 +99,25 @@ internal inline fun <T, A : Algebra<T>> BufferAlgebraND<T, A>.zipInline(
 @OptIn(PerformancePitfall::class)
 public open class BufferedGroupNDOps<T, out A : Group<T>>(
     override val bufferAlgebra: BufferAlgebra<T, A>,
-    override val indexerBuilder: (IntArray) -> ShapeIndexer = BufferAlgebraND.defaultIndexerBuilder,
+    override val indexerBuilder: (IntArray) -> ShapeIndices = BufferAlgebraND.defaultIndexerBuilder,
 ) : GroupOpsND<T, A>, BufferAlgebraND<T, A> {
     override fun StructureND<T>.unaryMinus(): StructureND<T> = map { -it }
 }
 
 public open class BufferedRingOpsND<T, out A : Ring<T>>(
     bufferAlgebra: BufferAlgebra<T, A>,
-    indexerBuilder: (IntArray) -> ShapeIndexer = BufferAlgebraND.defaultIndexerBuilder,
+    indexerBuilder: (IntArray) -> ShapeIndices = BufferAlgebraND.defaultIndexerBuilder,
 ) : BufferedGroupNDOps<T, A>(bufferAlgebra, indexerBuilder), RingOpsND<T, A>
 
 public open class BufferedFieldOpsND<T, out A : Field<T>>(
     bufferAlgebra: BufferAlgebra<T, A>,
-    indexerBuilder: (IntArray) -> ShapeIndexer = BufferAlgebraND.defaultIndexerBuilder,
+    indexerBuilder: (IntArray) -> ShapeIndices = BufferAlgebraND.defaultIndexerBuilder,
 ) : BufferedRingOpsND<T, A>(bufferAlgebra, indexerBuilder), FieldOpsND<T, A> {
 
     public constructor(
         elementAlgebra: A,
         bufferFactory: BufferFactory<T>,
-        indexerBuilder: (IntArray) -> ShapeIndexer = BufferAlgebraND.defaultIndexerBuilder,
+        indexerBuilder: (IntArray) -> ShapeIndices = BufferAlgebraND.defaultIndexerBuilder,
     ) : this(BufferFieldOps(elementAlgebra, bufferFactory), indexerBuilder)
 
     @OptIn(PerformancePitfall::class)

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

@@ -14,17 +14,17 @@ import space.kscience.kmath.structures.MutableBufferFactory
  * Represents [StructureND] over [Buffer].
  *
  * @param T the type of items.
- * @param indices The strides to access elements of [Buffer] by linear indices.
+ * @param shapeIndices The strides to access elements of [Buffer] by linear indices.
  * @param buffer The underlying buffer.
  */
 public open class BufferND<out T>(
-    override val indices: ShapeIndexer,
+    override val shapeIndices: ShapeIndices,
     public open val buffer: Buffer<T>,
 ) : StructureND<T> {
 
-    override operator fun get(index: IntArray): T = buffer[indices.offset(index)]
+    override operator fun get(index: IntArray): T = buffer[shapeIndices.offset(index)]
 
-    override val shape: IntArray get() = indices.shape
+    override val shape: IntArray get() = shapeIndices.shape
 
     override fun toString(): String = StructureND.toString(this)
 }
@@ -37,7 +37,7 @@ public inline fun <T, reified R : Any> StructureND<T>.mapToBuffer(
     crossinline transform: (T) -> R,
 ): BufferND<R> {
     return if (this is BufferND<T>)
-        BufferND(this.indices, factory.invoke(indices.linearSize) { transform(buffer[it]) })
+        BufferND(this.shapeIndices, factory.invoke(shapeIndices.linearSize) { transform(buffer[it]) })
     else {
         val strides = DefaultStrides(shape)
         BufferND(strides, factory.invoke(strides.linearSize) { transform(get(strides.index(it))) })
@@ -52,11 +52,11 @@ public inline fun <T, reified R : Any> StructureND<T>.mapToBuffer(
  * @param buffer The underlying buffer.
  */
 public class MutableBufferND<T>(
-    strides: ShapeIndexer,
+    strides: ShapeIndices,
     override val buffer: MutableBuffer<T>,
 ) : MutableStructureND<T>, BufferND<T>(strides, buffer) {
     override fun set(index: IntArray, value: T) {
-        buffer[indices.offset(index)] = value
+        buffer[shapeIndices.offset(index)] = value
     }
 }
 
@@ -68,7 +68,7 @@ public inline fun <T, reified R : Any> MutableStructureND<T>.mapToMutableBuffer(
     crossinline transform: (T) -> R,
 ): MutableBufferND<R> {
     return if (this is MutableBufferND<T>)
-        MutableBufferND(this.indices, factory.invoke(indices.linearSize) { transform(buffer[it]) })
+        MutableBufferND(this.shapeIndices, factory.invoke(shapeIndices.linearSize) { transform(buffer[it]) })
     else {
         val strides = DefaultStrides(shape)
         MutableBufferND(strides, factory.invoke(strides.linearSize) { transform(get(strides.index(it))) })

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

@@ -14,7 +14,7 @@ import kotlin.contracts.contract
 import kotlin.math.pow as kpow
 
 public class DoubleBufferND(
-    indexes: ShapeIndexer,
+    indexes: ShapeIndices,
     override val buffer: DoubleBuffer,
 ) : BufferND<Double>(indexes, buffer)
 
@@ -34,7 +34,7 @@ public sealed class DoubleFieldOpsND : BufferedFieldOpsND<Double, DoubleField>(D
         arg: DoubleBufferND,
         transform: (Double) -> Double,
     ): DoubleBufferND {
-        val indexes = arg.indices
+        val indexes = arg.shapeIndices
         val array = arg.buffer.array
         return DoubleBufferND(indexes, DoubleBuffer(indexes.linearSize) { transform(array[it]) })
     }
@@ -44,8 +44,8 @@ public sealed class DoubleFieldOpsND : BufferedFieldOpsND<Double, DoubleField>(D
         r: DoubleBufferND,
         block: (l: Double, r: Double) -> Double,
     ): DoubleBufferND {
-        require(l.indices == r.indices) { "Zip requires the same shapes, but found ${l.shape} on the left and ${r.shape} on the right" }
+        require(l.shapeIndices == r.shapeIndices) { "Zip requires the same shapes, but found ${l.shape} on the left and ${r.shape} on the right" }
-        val indexes = l.indices
+        val indexes = l.shapeIndices
         val lArray = l.buffer.array
         val rArray = r.buffer.array
         return DoubleBufferND(indexes, DoubleBuffer(indexes.linearSize) { block(lArray[it], rArray[it]) })

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

@@ -10,7 +10,7 @@ import kotlin.native.concurrent.ThreadLocal
 /**
  * A converter from linear index to multivariate index
  */
-public interface ShapeIndexer: Iterable<IntArray>{
+public interface ShapeIndices: Iterable<IntArray>{
     public val shape: Shape
 
     /**
@@ -44,7 +44,7 @@ public interface ShapeIndexer: Iterable<IntArray>{
 /**
  * Linear transformation of indexes
  */
-public abstract class Strides: ShapeIndexer {
+public abstract class Strides: ShapeIndices {
     /**
      * Array strides
      */

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

@@ -54,7 +54,7 @@ public interface StructureND<out T> : Featured<StructureFeature>, WithShape {
      * @return the lazy sequence of pairs of indices to values.
      */
     @PerformancePitfall
-    public fun elements(): Sequence<Pair<IntArray, T>> = indices.asSequence().map { it to get(it) }
+    public fun elements(): Sequence<Pair<IntArray, T>> = shapeIndices.asSequence().map { it to get(it) }
 
     /**
      * Feature is some additional structure information that allows to access it special properties or hints.
@@ -71,7 +71,7 @@ public interface StructureND<out T> : Featured<StructureFeature>, WithShape {
             if (st1 === st2) return true
 
             // fast comparison of buffers if possible
-            if (st1 is BufferND && st2 is BufferND && st1.indices == st2.indices)
+            if (st1 is BufferND && st2 is BufferND && st1.shapeIndices == st2.shapeIndices)
                 return Buffer.contentEquals(st1.buffer, st2.buffer)
 
             //element by element comparison if it could not be avoided
@@ -87,7 +87,7 @@ public interface StructureND<out T> : Featured<StructureFeature>, WithShape {
             if (st1 === st2) return true
 
             // fast comparison of buffers if possible
-            if (st1 is BufferND && st2 is BufferND && st1.indices == st2.indices)
+            if (st1 is BufferND && st2 is BufferND && st1.shapeIndices == st2.shapeIndices)
                 return Buffer.contentEquals(st1.buffer, st2.buffer)
 
             //element by element comparison if it could not be avoided

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

@@ -61,14 +61,14 @@ public inline fun <reified T> Buffer<T>.toTypedArray(): Array<T> = Array(size, :
 /**
  * Create a new buffer from this one with the given mapping function and using [Buffer.Companion.auto] buffer factory.
  */
-public inline fun <T : Any, reified R : Any> Buffer<T>.map(block: (T) -> R): Buffer<R> =
+public inline fun <T, reified R : Any> Buffer<T>.map(block: (T) -> R): Buffer<R> =
     Buffer.auto(size) { block(get(it)) }
 
 /**
  * Create a new buffer from this one with the given mapping function.
  * Provided [bufferFactory] is used to construct the new buffer.
  */
-public inline fun <T : Any, R : Any> Buffer<T>.map(
+public inline fun <T, R> Buffer<T>.map(
     bufferFactory: BufferFactory<R>,
     crossinline block: (T) -> R,
 ): Buffer<R> = bufferFactory(size) { block(get(it)) }
@@ -77,15 +77,16 @@ public inline fun <T : Any, R : Any> Buffer<T>.map(
  * Create a new buffer from this one with the given indexed mapping function.
  * Provided [BufferFactory] is used to construct the new buffer.
  */
-public inline fun <T : Any, reified R : Any> Buffer<T>.mapIndexed(
+public inline fun <T, reified R : Any> Buffer<T>.mapIndexed(
     bufferFactory: BufferFactory<R> = Buffer.Companion::auto,
     crossinline block: (index: Int, value: T) -> R,
 ): Buffer<R> = bufferFactory(size) { block(it, get(it)) }
 
 /**
  * Fold given buffer according to [operation]
+ * TODO add element algebra as fold receiver
  */
-public inline fun <T : Any, R> Buffer<T>.fold(initial: R, operation: (acc: R, T) -> R): R {
+public inline fun <T, R> Buffer<T>.fold(initial: R, operation: (acc: R, T) -> R): R {
     var accumulator = initial
     for (index in this.indices) accumulator = operation(accumulator, get(index))
     return accumulator
@@ -95,7 +96,7 @@ public inline fun <T : Any, R> Buffer<T>.fold(initial: R, operation: (acc: R, T)
  * Zip two buffers using given [transform].
  */
 @UnstableKMathAPI
-public inline fun <T1 : Any, T2 : Any, reified R : Any> Buffer<T1>.zip(
+public inline fun <T1, T2, reified R : Any> Buffer<T1>.zip(
     other: Buffer<T2>,
     bufferFactory: BufferFactory<R> = Buffer.Companion::auto,
     crossinline transform: (T1, T2) -> R,

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

@@ -48,6 +48,11 @@ public interface Buffer<out T> {
 
     override fun toString(): String
 
+    /**
+     * Returns an [IntRange] of the valid indices for this [Buffer].
+     */
+    public val indices: IntRange get() = 0 until size
+
     public companion object {
 
         public fun toString(buffer: Buffer<*>): String =
@@ -100,10 +105,12 @@ public interface Buffer<out T> {
     }
 }
 
+public operator fun<T> Buffer<T>.get(index: UInt): T = get(index.toInt())
+
 /**
- * Returns an [IntRange] of the valid indices for this [Buffer].
+ * if index is in range of buffer, return the value. Otherwise, return null.
  */
-public val Buffer<*>.indices: IntRange get() = 0 until size
+public fun <T> Buffer<T>.getOrNull(index: Int): T? = if (index in indices) get(index) else null
 
 /**
  * Immutable wrapper for [MutableBuffer].

kmath-for-real/src/commonMain/kotlin/space/kscience/kmath/real/RealVector.kt

@@ -11,7 +11,6 @@ import space.kscience.kmath.operations.DoubleL2Norm
 import space.kscience.kmath.structures.Buffer
 import space.kscience.kmath.structures.MutableBuffer.Companion.double
 import space.kscience.kmath.structures.asBuffer
-import space.kscience.kmath.structures.indices
 import kotlin.math.pow
 
 public typealias DoubleVector = Point<Double>

kmath-for-real/src/commonMain/kotlin/space/kscience/kmath/real/realND.kt

@@ -13,8 +13,8 @@ import space.kscience.kmath.structures.DoubleBuffer
  * Map one [BufferND] using function without indices.
  */
 public inline fun BufferND<Double>.mapInline(crossinline transform: DoubleField.(Double) -> Double): BufferND<Double> {
-    val array = DoubleArray(indices.linearSize) { offset -> DoubleField.transform(buffer[offset]) }
+    val array = DoubleArray(shapeIndices.linearSize) { offset -> DoubleField.transform(buffer[offset]) }
-    return BufferND(indices, DoubleBuffer(array))
+    return BufferND(shapeIndices, DoubleBuffer(array))
 }
 
 /**

kmath-functions/src/commonMain/kotlin/space/kscience/kmath/integration/GaussIntegrator.kt

@@ -8,7 +8,6 @@ import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.operations.Field
 import space.kscience.kmath.structures.Buffer
 import space.kscience.kmath.structures.asBuffer
-import space.kscience.kmath.structures.indices
 
 /**
  * A simple one-pass integrator based on Gauss rule

kmath-stat/src/commonMain/kotlin/space/kscience/kmath/series/SeriesAlgebra.kt

@@ -0,0 +1,170 @@
+package space.kscience.kmath.series
+
+import space.kscience.kmath.operations.*
+import space.kscience.kmath.structures.Buffer
+import space.kscience.kmath.structures.BufferFactory
+import space.kscience.kmath.structures.getOrNull
+import kotlin.math.max
+import kotlin.math.min
+
+private fun IntRange.intersect(other: IntRange): IntRange =
+    max(first, other.first)..min(last, other.last)
+
+private val IntRange.size get() = last - first + 1
+
+private class BufferView<T>(val buffer: Buffer<T>, val offset: Int, override val size: Int) : Buffer<T> {
+    init {
+        require(offset >= 0) { " Range offset must be positive" }
+        require(offset < buffer.size) { "Range offset is beyond the buffer size" }
+        require(size > 0) { "Size must be positive" }
+        require(size < buffer.size) { "Slice size is larger than the buffer" }
+    }
+
+    override fun get(index: Int): T = buffer[index - offset]
+
+    override fun iterator(): Iterator<T> = buffer.asSequence().drop(offset).take(size).iterator()
+
+    override fun toString(): String = "$buffer[${offset}:${offset + size - 1}]"
+
+    override val indices: IntRange = offset until offset + size
+}
+
+/**
+ * A scope to operation on series
+ */
+public class SeriesAlgebra<T, A : Ring<T>, L>(
+    public val bufferAlgebra: BufferRingOps<T, A>,
+    private val labelResolver: (Int) -> L,
+) : RingOps<Buffer<T>> {
+
+    public val elementAlgebra: A get() = bufferAlgebra.elementAlgebra
+    public val bufferFactory: BufferFactory<T> get() = bufferAlgebra.bufferFactory
+
+    public val Buffer<T>.offset: UInt get() = indices.first.toUInt()
+
+    /**
+     * Build a new series
+     */
+    public fun series(size: Int, fromIndex: Int = 0, block: A.(label: L) -> T): Buffer<T> {
+        return bufferFactory(size) {
+            val index = it + fromIndex
+            elementAlgebra.block(labelResolver(index))
+        }.moveTo(fromIndex)
+    }
+
+    /**
+     * Move a series starting to start at a given index
+     */
+    public fun Buffer<T>.moveTo(index: Int): Buffer<T> = if (index == 0) {
+        this
+    } else if (this is BufferView) {
+        BufferView(buffer, index.toInt(), size)
+    } else {
+        BufferView(this, index.toInt(), size)
+    }
+
+    /**
+     * Create a buffer view using given range
+     */
+    public fun Buffer<T>.get(range: IntRange): Buffer<T> {
+        val size = range.size
+        return if (this is BufferView) {
+            BufferView(this, indices.first + range.first, size)
+        } else {
+            BufferView(this, range.first, size)
+        }
+    }
+
+    /**
+     * Get a label buffer for given buffer.
+     */
+    public val Buffer<T>.labels: List<L> get() = indices.map(labelResolver)
+
+
+    /**
+     * Try to resolve element by label and return null if element with a given label is not found
+     */
+    public operator fun Buffer<T>.get(label: L): T? {
+        val index = labels.indexOf(label)
+        if (index == -1) return null
+        return get(index + offset.toInt())
+    }
+
+    override fun add(left: Buffer<T>, right: Buffer<T>): Buffer<T> = elementAlgebra.invoke {
+        val newRange = left.indices.intersect(right.indices)
+        //TODO optimize copy at BufferAlgebra level
+        bufferFactory(newRange.size) {
+            val offset = it + newRange.first
+            left[offset] + right[offset]
+        }.moveTo(newRange.first)
+    }
+
+    override fun Buffer<T>.unaryMinus(): Buffer<T> = map { -it }
+
+    override fun multiply(left: Buffer<T>, right: Buffer<T>): Buffer<T> = elementAlgebra.invoke {
+        val newRange = left.indices.intersect(right.indices)
+        bufferFactory(newRange.size) {
+            val offset = it + newRange.first
+            left[offset] * right[offset]
+        }
+    }
+
+    /**
+     * Map a series to another series of the same size
+     */
+    public inline fun Buffer<T>.map(crossinline transform: A.(T) -> T): Buffer<T> {
+        val buf = bufferFactory(size) {
+            elementAlgebra.transform(get(it))
+        }
+        return buf.moveTo(indices.first)
+    }
+
+    /**
+     * Map series to another series of the same size with label
+     */
+    public inline fun Buffer<T>.mapWithLabel(crossinline transform: A.(arg: T, label: L) -> T): Buffer<T> {
+        val labels = labels
+        val buf = bufferFactory(size) {
+            elementAlgebra.transform(get(it), labels[it])
+        }
+        return buf.moveTo(indices.first)
+    }
+
+    public inline fun <R> Buffer<T>.fold(initial: R, operation: A.(acc: R, T) -> R): R {
+        var accumulator = initial
+        for (index in this.indices) accumulator = elementAlgebra.operation(accumulator, get(index))
+        return accumulator
+    }
+
+    public inline fun <R> Buffer<T>.foldWithLabel(initial: R, operation: A.(acc: R, arg: T, label: L) -> R): R {
+        val labels = labels
+        var accumulator = initial
+        for (index in this.indices) accumulator = elementAlgebra.operation(accumulator, get(index), labels[index])
+        return accumulator
+    }
+
+    /**
+     * Zip two buffers replacing missing values with [defaultValue]
+     */
+    public inline fun Buffer<T>.zip(
+        other: Buffer<T>,
+        defaultValue: T,
+        crossinline operation: A.(left: T?, right: T?) -> T?,
+    ): Buffer<T> {
+        val start = min(indices.first, other.indices.first)
+        val size = max(indices.last, other.indices.last) - start
+        return bufferFactory(size) {
+            elementAlgebra.operation(
+                getOrNull(it) ?: defaultValue,
+                other.getOrNull(it) ?: defaultValue
+            ) ?: defaultValue
+        }
+    }
+}
+
+public fun <T, A : Ring<T>, L> BufferRingOps<T, A>.seriesAlgebra(labels: Iterable<L>): SeriesAlgebra<T, A, L> {
+    val l = labels.toList()
+    return SeriesAlgebra(this) {
+        if (it in l.indices) l[it] else error("Index $it is outside of labels range ${l.indices}")
+    }
+}

kmath-stat/src/commonMain/kotlin/space/kscience/kmath/stat/Mean.kt

@@ -7,7 +7,6 @@ package space.kscience.kmath.stat
 
 import space.kscience.kmath.operations.*
 import space.kscience.kmath.structures.Buffer
-import space.kscience.kmath.structures.indices
 
 /**
  * Arithmetic mean
@@ -45,8 +44,10 @@ public class Mean<T>(
     public companion object {
         @Deprecated("Use Double.mean instead")
         public val double: Mean<Double> = Mean(DoubleField) { sum, count -> sum / count }
+
         @Deprecated("Use Int.mean instead")
         public val int: Mean<Int> = Mean(IntRing) { sum, count -> sum / count }
+
         @Deprecated("Use Long.mean instead")
         public val long: Mean<Long> = Mean(LongRing) { sum, count -> sum / count }
 
@@ -60,6 +61,6 @@ public class Mean<T>(
 //TODO replace with optimized version which respects overflow
 public val Double.Companion.mean: Mean<Double> get() = Mean(DoubleField) { sum, count -> sum / count }
 public val Int.Companion.mean: Mean<Int> get() = Mean(IntRing) { sum, count -> sum / count }
-public val Long.Companion.mean: Mean<Long> get() =  Mean(LongRing) { sum, count -> sum / count }
+public val Long.Companion.mean: Mean<Long> get() = Mean(LongRing) { sum, count -> sum / count }
 
 

kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/BroadcastDoubleTensorAlgebra.kt

@@ -26,7 +26,7 @@ public object BroadcastDoubleTensorAlgebra : DoubleTensorAlgebra() {
         val broadcast = broadcastTensors(tensor, arg.tensor)
         val newThis = broadcast[0]
         val newOther = broadcast[1]
-        val resBuffer = DoubleArray(newThis.indices.linearSize) { i ->
+        val resBuffer = DoubleArray(newThis.shapeIndices.linearSize) { i ->
             newThis.mutableBuffer.array()[i] + newOther.mutableBuffer.array()[i]
         }
         return DoubleTensor(newThis.shape, resBuffer)
@@ -34,7 +34,7 @@ public object BroadcastDoubleTensorAlgebra : DoubleTensorAlgebra() {
 
     override fun Tensor<Double>.plusAssign(arg: StructureND<Double>) {
         val newOther = broadcastTo(arg.tensor, tensor.shape)
-        for (i in 0 until tensor.indices.linearSize) {
+        for (i in 0 until tensor.shapeIndices.linearSize) {
             tensor.mutableBuffer.array()[tensor.bufferStart + i] +=
                 newOther.mutableBuffer.array()[tensor.bufferStart + i]
         }
@@ -44,7 +44,7 @@ public object BroadcastDoubleTensorAlgebra : DoubleTensorAlgebra() {
         val broadcast = broadcastTensors(tensor, arg.tensor)
         val newThis = broadcast[0]
         val newOther = broadcast[1]
-        val resBuffer = DoubleArray(newThis.indices.linearSize) { i ->
+        val resBuffer = DoubleArray(newThis.shapeIndices.linearSize) { i ->
             newThis.mutableBuffer.array()[i] - newOther.mutableBuffer.array()[i]
         }
         return DoubleTensor(newThis.shape, resBuffer)
@@ -52,7 +52,7 @@ public object BroadcastDoubleTensorAlgebra : DoubleTensorAlgebra() {
 
     override fun Tensor<Double>.minusAssign(arg: StructureND<Double>) {
         val newOther = broadcastTo(arg.tensor, tensor.shape)
-        for (i in 0 until tensor.indices.linearSize) {
+        for (i in 0 until tensor.shapeIndices.linearSize) {
             tensor.mutableBuffer.array()[tensor.bufferStart + i] -=
                 newOther.mutableBuffer.array()[tensor.bufferStart + i]
         }
@@ -62,7 +62,7 @@ public object BroadcastDoubleTensorAlgebra : DoubleTensorAlgebra() {
         val broadcast = broadcastTensors(tensor, arg.tensor)
         val newThis = broadcast[0]
         val newOther = broadcast[1]
-        val resBuffer = DoubleArray(newThis.indices.linearSize) { i ->
+        val resBuffer = DoubleArray(newThis.shapeIndices.linearSize) { i ->
             newThis.mutableBuffer.array()[newThis.bufferStart + i] *
                     newOther.mutableBuffer.array()[newOther.bufferStart + i]
         }
@@ -71,7 +71,7 @@ public object BroadcastDoubleTensorAlgebra : DoubleTensorAlgebra() {
 
     override fun Tensor<Double>.timesAssign(arg: StructureND<Double>) {
         val newOther = broadcastTo(arg.tensor, tensor.shape)
-        for (i in 0 until tensor.indices.linearSize) {
+        for (i in 0 until tensor.shapeIndices.linearSize) {
             tensor.mutableBuffer.array()[tensor.bufferStart + i] *=
                 newOther.mutableBuffer.array()[tensor.bufferStart + i]
         }
@@ -81,7 +81,7 @@ public object BroadcastDoubleTensorAlgebra : DoubleTensorAlgebra() {
         val broadcast = broadcastTensors(tensor, arg.tensor)
         val newThis = broadcast[0]
         val newOther = broadcast[1]
-        val resBuffer = DoubleArray(newThis.indices.linearSize) { i ->
+        val resBuffer = DoubleArray(newThis.shapeIndices.linearSize) { i ->
             newThis.mutableBuffer.array()[newOther.bufferStart + i] /
                     newOther.mutableBuffer.array()[newOther.bufferStart + i]
         }
@@ -90,7 +90,7 @@ public object BroadcastDoubleTensorAlgebra : DoubleTensorAlgebra() {
 
     override fun Tensor<Double>.divAssign(arg: StructureND<Double>) {
         val newOther = broadcastTo(arg.tensor, tensor.shape)
-        for (i in 0 until tensor.indices.linearSize) {
+        for (i in 0 until tensor.shapeIndices.linearSize) {
             tensor.mutableBuffer.array()[tensor.bufferStart + i] /=
                 newOther.mutableBuffer.array()[tensor.bufferStart + i]
         }

kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/BufferedTensor.kt

@@ -22,22 +22,22 @@ public open class BufferedTensor<T> internal constructor(
     /**
      * Buffer strides based on [TensorLinearStructure] implementation
      */
-    override val indices: Strides get() = TensorLinearStructure(shape)
+    override val shapeIndices: Strides get() = TensorLinearStructure(shape)
 
     /**
      * Number of elements in tensor
      */
     public val numElements: Int
-        get() = indices.linearSize
+        get() = shapeIndices.linearSize
 
-    override fun get(index: IntArray): T = mutableBuffer[bufferStart + indices.offset(index)]
+    override fun get(index: IntArray): T = mutableBuffer[bufferStart + shapeIndices.offset(index)]
 
     override fun set(index: IntArray, value: T) {
-        mutableBuffer[bufferStart + indices.offset(index)] = value
+        mutableBuffer[bufferStart + shapeIndices.offset(index)] = value
     }
 
     @PerformancePitfall
-    override fun elements(): Sequence<Pair<IntArray, T>> = indices.asSequence().map {
+    override fun elements(): Sequence<Pair<IntArray, T>> = shapeIndices.asSequence().map {
         it to get(it)
     }
 }

kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/DoubleTensorAlgebra.kt

@@ -15,7 +15,6 @@ import space.kscience.kmath.nd.as1D
 import space.kscience.kmath.nd.as2D
 import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.structures.MutableBuffer
-import space.kscience.kmath.structures.indices
 import space.kscience.kmath.tensors.api.AnalyticTensorAlgebra
 import space.kscience.kmath.tensors.api.LinearOpsTensorAlgebra
 import space.kscience.kmath.tensors.api.Tensor
@@ -63,7 +62,7 @@ public open class DoubleTensorAlgebra :
         val tensor = this.tensor
         //TODO remove additional copy
         val sourceArray = tensor.copyArray()
-        val array = DoubleArray(tensor.numElements) { DoubleField.transform(tensor.indices.index(it), sourceArray[it]) }
+        val array = DoubleArray(tensor.numElements) { DoubleField.transform(tensor.shapeIndices.index(it), sourceArray[it]) }
         return DoubleTensor(
             tensor.shape,
             array,
@@ -365,11 +364,11 @@ public open class DoubleTensorAlgebra :
         val resTensor = DoubleTensor(resShape, resBuffer)
 
         for (offset in 0 until n) {
-            val oldMultiIndex = tensor.indices.index(offset)
+            val oldMultiIndex = tensor.shapeIndices.index(offset)
             val newMultiIndex = oldMultiIndex.copyOf()
             newMultiIndex[ii] = newMultiIndex[jj].also { newMultiIndex[jj] = newMultiIndex[ii] }
 
-            val linearIndex = resTensor.indices.offset(newMultiIndex)
+            val linearIndex = resTensor.shapeIndices.offset(newMultiIndex)
             resTensor.mutableBuffer.array()[linearIndex] =
                 tensor.mutableBuffer.array()[tensor.bufferStart + offset]
         }
@@ -467,7 +466,7 @@ public open class DoubleTensorAlgebra :
         val resTensor = zeros(resShape)
 
         for (i in 0 until diagonalEntries.tensor.numElements) {
-            val multiIndex = diagonalEntries.tensor.indices.index(i)
+            val multiIndex = diagonalEntries.tensor.shapeIndices.index(i)
 
             var offset1 = 0
             var offset2 = abs(realOffset)
@@ -592,7 +591,7 @@ public open class DoubleTensorAlgebra :
         val init = foldFunction(DoubleArray(1) { 0.0 })
         val resTensor = BufferedTensor(resShape,
             MutableBuffer.auto(resNumElements) { init }, 0)
-        for (index in resTensor.indices) {
+        for (index in resTensor.shapeIndices) {
             val prefix = index.take(dim).toIntArray()
             val suffix = index.takeLast(dimension - dim - 1).toIntArray()
             resTensor[index] = foldFunction(DoubleArray(shape[dim]) { i ->

kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/internal/broadcastUtils.kt

@@ -10,7 +10,7 @@ import kotlin.math.max
 
 internal fun multiIndexBroadCasting(tensor: DoubleTensor, resTensor: DoubleTensor, linearSize: Int) {
     for (linearIndex in 0 until linearSize) {
-        val totalMultiIndex = resTensor.indices.index(linearIndex)
+        val totalMultiIndex = resTensor.shapeIndices.index(linearIndex)
         val curMultiIndex = tensor.shape.copyOf()
 
         val offset = totalMultiIndex.size - curMultiIndex.size
@@ -23,7 +23,7 @@ internal fun multiIndexBroadCasting(tensor: DoubleTensor, resTensor: DoubleTenso
             }
         }
 
-        val curLinearIndex = tensor.indices.offset(curMultiIndex)
+        val curLinearIndex = tensor.shapeIndices.offset(curMultiIndex)
         resTensor.mutableBuffer.array()[linearIndex] =
             tensor.mutableBuffer.array()[tensor.bufferStart + curLinearIndex]
     }
@@ -112,7 +112,7 @@ internal fun broadcastOuterTensors(vararg tensors: DoubleTensor): List<DoubleTen
             val resTensor = DoubleTensor(totalShape + matrixShape, DoubleArray(n * matrixSize))
 
             for (linearIndex in 0 until n) {
-                val totalMultiIndex = outerTensor.indices.index(linearIndex)
+                val totalMultiIndex = outerTensor.shapeIndices.index(linearIndex)
                 var curMultiIndex = tensor.shape.sliceArray(0..tensor.shape.size - 3).copyOf()
                 curMultiIndex = IntArray(totalMultiIndex.size - curMultiIndex.size) { 1 } + curMultiIndex
 
@@ -127,13 +127,13 @@ internal fun broadcastOuterTensors(vararg tensors: DoubleTensor): List<DoubleTen
                 }
 
                 for (i in 0 until matrixSize) {
-                    val curLinearIndex = newTensor.indices.offset(
+                    val curLinearIndex = newTensor.shapeIndices.offset(
                         curMultiIndex +
-                                matrix.indices.index(i)
+                                matrix.shapeIndices.index(i)
                     )
-                    val newLinearIndex = resTensor.indices.offset(
+                    val newLinearIndex = resTensor.shapeIndices.offset(
                         totalMultiIndex +
-                                matrix.indices.index(i)
+                                matrix.shapeIndices.index(i)
                     )
 
                     resTensor.mutableBuffer.array()[resTensor.bufferStart + newLinearIndex] =

kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/internal/linUtils.kt

@@ -3,8 +3,11 @@
  * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
  */
 
+@file:OptIn(PerformancePitfall::class)
+
 package space.kscience.kmath.tensors.core.internal
 
+import space.kscience.kmath.misc.PerformancePitfall
 import space.kscience.kmath.nd.MutableStructure1D
 import space.kscience.kmath.nd.MutableStructure2D
 import space.kscience.kmath.nd.as1D

kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/internal/tensorCastsUtils.kt

@@ -28,7 +28,7 @@ internal fun <T> StructureND<T>.copyToBufferedTensor(): BufferedTensor<T> =
 
 internal fun <T> StructureND<T>.toBufferedTensor(): BufferedTensor<T> = when (this) {
     is BufferedTensor<T> -> this
-    is MutableBufferND<T> -> if (this.indices == TensorLinearStructure(this.shape)) {
+    is MutableBufferND<T> -> if (this.shapeIndices == TensorLinearStructure(this.shape)) {
         BufferedTensor(this.shape, this.buffer, 0)
     } else {
         this.copyToBufferedTensor()

kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/internal/utils.kt

@@ -85,7 +85,7 @@ internal fun format(value: Double, digits: Int = 4): String = buildString {
 internal fun DoubleTensor.toPrettyString(): String = buildString {
     var offset = 0
     val shape = this@toPrettyString.shape
-    val linearStructure = this@toPrettyString.indices
+    val linearStructure = this@toPrettyString.shapeIndices
     val vectorSize = shape.last()
     append("DoubleTensor(\n")
     var charOffset = 3

settings.gradle.kts

@@ -5,8 +5,8 @@ pluginManagement {
         gradlePluginPortal()
     }
 
-    val kotlinVersion = "1.6.0-RC"
+    val kotlinVersion = "1.6.0-RC2"
-    val toolsVersion = "0.10.5"
+    val toolsVersion = "0.10.6"
 
     plugins {
         id("org.jetbrains.kotlinx.benchmark") version "0.3.1"