refactor BT + docs

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

@@ -1,116 +1,48 @@
 package space.kscience.kmath.tensors.core
 
-import space.kscience.kmath.nd.MutableBufferND
 import space.kscience.kmath.structures.*
 import space.kscience.kmath.tensors.api.Tensor
 import space.kscience.kmath.tensors.core.algebras.TensorLinearStructure
 
-
-public open class BufferedTensor<T>(
+/**
+ * [Tensor] implementation provided with [MutableBuffer]
+ */
+public open class BufferedTensor<T> internal constructor(
     override val shape: IntArray,
     internal val mutableBuffer: MutableBuffer<T>,
     internal val bufferStart: Int
 ) : Tensor<T> {
+
+    /**
+     * [TensorLinearStructure] with the same shape
+     */
     public val linearStructure: TensorLinearStructure
         get() = TensorLinearStructure(shape)
 
+    /**
+     * Number of elements in tensor
+     */
     public val numElements: Int
         get() = linearStructure.linearSize
 
+    /**
+     * @param index [IntArray] with size equal to tensor dimension
+     * @return the element by multidimensional index
+     */
     override fun get(index: IntArray): T = mutableBuffer[bufferStart + linearStructure.offset(index)]
 
+    /**
+     * @param index the [IntArray] with size equal to tensor dimension
+     * @param value the value to set
+     */
     override fun set(index: IntArray, value: T) {
         mutableBuffer[bufferStart + linearStructure.offset(index)] = value
     }
 
+    /**
+     * @return the sequence of pairs multidimensional indices and values
+     */
     override fun elements(): Sequence<Pair<IntArray, T>> = linearStructure.indices().map {
         it to this[it]
     }
 }
-
-public class IntTensor internal constructor(
-    shape: IntArray,
-    buffer: IntArray,
-    offset: Int = 0
-) : BufferedTensor<Int>(shape, IntBuffer(buffer), offset)
-
-public class DoubleTensor internal constructor(
-    shape: IntArray,
-    buffer: DoubleArray,
-    offset: Int = 0
-) : BufferedTensor<Double>(shape, DoubleBuffer(buffer), offset) {
-    override fun toString(): String = toPrettyString()
-}
-
-internal fun BufferedTensor<Int>.asTensor(): IntTensor =
-    IntTensor(this.shape, this.mutableBuffer.array(), this.bufferStart)
-
-internal fun BufferedTensor<Double>.asTensor(): DoubleTensor =
-    DoubleTensor(this.shape, this.mutableBuffer.array(), this.bufferStart)
-
-internal fun <T> Tensor<T>.copyToBufferedTensor(): BufferedTensor<T> =
-    BufferedTensor(
-        this.shape,
-        TensorLinearStructure(this.shape).indices().map(this::get).toMutableList().asMutableBuffer(), 0
-    )
-
-internal fun <T> Tensor<T>.toBufferedTensor(): BufferedTensor<T> = when (this) {
-    is BufferedTensor<T> -> this
-    is MutableBufferND<T> -> if (this.strides.strides contentEquals TensorLinearStructure(this.shape).strides)
-        BufferedTensor(this.shape, this.mutableBuffer, 0) else this.copyToBufferedTensor()
-    else -> this.copyToBufferedTensor()
-}
-
-internal val Tensor<Double>.tensor: DoubleTensor
-    get() = when (this) {
-        is DoubleTensor -> this
-        else -> this.toBufferedTensor().asTensor()
-    }
-
-internal val Tensor<Int>.tensor: IntTensor
-    get() = when (this) {
-        is IntTensor -> this
-        else -> this.toBufferedTensor().asTensor()
-    }
-
-public fun Tensor<Double>.toDoubleTensor(): DoubleTensor = this.tensor
-public fun Tensor<Int>.toIntTensor(): IntTensor = this.tensor
-
-public fun Array<DoubleArray>.toDoubleTensor(): DoubleTensor {
-    val n = size
-    check(n > 0) { "An empty array cannot be casted to tensor" }
-    val m = first().size
-    check(m > 0) { "Inner arrays must have at least 1 argument" }
-    check(all { size == m }) { "Inner arrays must be the same size" }
-
-    val shape = intArrayOf(n, m)
-    val buffer = this.flatMap { arr -> arr.map { it } }.toDoubleArray()
-
-    return DoubleTensor(shape, buffer, 0)
-}
-
-
-public fun Array<IntArray>.toIntTensor(): IntTensor {
-    val n = size
-    check(n > 0) { "An empty array cannot be casted to tensor" }
-    val m = first().size
-    check(m > 0) { "Inner arrays must have at least 1 argument" }
-    check(all { size == m }) { "Inner arrays must be the same size" }
-
-    val shape = intArrayOf(n, m)
-    val buffer = this.flatMap { arr -> arr.map { it } }.toIntArray()
-
-    return IntTensor(shape, buffer, 0)
-}
-
-public fun DoubleTensor.toDoubleArray(): DoubleArray {
-    return DoubleArray(numElements) { i ->
-        mutableBuffer[bufferStart + i]
-    }
-}
-
-public fun IntTensor.toIntArray(): IntArray {
-    return IntArray(numElements) { i ->
-        mutableBuffer[bufferStart + i]
-    }
-}

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

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018-2021 KMath contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package space.kscience.kmath.tensors.core
+
+import space.kscience.kmath.structures.DoubleBuffer
+
+/**
+ * Default [BufferedTensor] implementation for [Double] values
+ */
+public class DoubleTensor internal constructor(
+    shape: IntArray,
+    buffer: DoubleArray,
+    offset: Int = 0
+) : BufferedTensor<Double>(shape, DoubleBuffer(buffer), offset) {
+    override fun toString(): String = toPrettyString()
+}

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

@@ -0,0 +1,17 @@
+/*
+ * Copyright 2018-2021 KMath contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package space.kscience.kmath.tensors.core
+
+import space.kscience.kmath.structures.IntBuffer
+
+/**
+ * Default [BufferedTensor] implementation for [Int] values
+ */
+public class IntTensor internal constructor(
+    shape: IntArray,
+    buffer: IntArray,
+    offset: Int = 0
+) : BufferedTensor<Int>(shape, IntBuffer(buffer), offset)

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

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2018-2021 KMath contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package space.kscience.kmath.tensors.core
+
+import space.kscience.kmath.tensors.api.Tensor
+
+/**
+ * Casts [Tensor<Double>] to [DoubleTensor]
+ */
+public fun Tensor<Double>.toDoubleTensor(): DoubleTensor = this.tensor
+
+/**
+ * Casts [Tensor<Int>] to [IntTensor]
+ */
+public fun Tensor<Int>.toIntTensor(): IntTensor = this.tensor
+
+/**
+ * @return [DoubleArray] of tensor elements
+ */
+public fun DoubleTensor.toDoubleArray(): DoubleArray {
+    return DoubleArray(numElements) { i ->
+        mutableBuffer[bufferStart + i]
+    }
+}
+
+/**
+ * @return [IntArray] of tensor elements
+ */
+public fun IntTensor.toIntArray(): IntArray {
+    return IntArray(numElements) { i ->
+        mutableBuffer[bufferStart + i]
+    }
+}

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

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2018-2021 KMath contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package space.kscience.kmath.tensors.core
+
+import space.kscience.kmath.nd.MutableBufferND
+import space.kscience.kmath.structures.asMutableBuffer
+import space.kscience.kmath.tensors.api.Tensor
+import space.kscience.kmath.tensors.core.algebras.TensorLinearStructure
+
+internal fun BufferedTensor<Int>.asTensor(): IntTensor =
+    IntTensor(this.shape, this.mutableBuffer.array(), this.bufferStart)
+
+internal fun BufferedTensor<Double>.asTensor(): DoubleTensor =
+    DoubleTensor(this.shape, this.mutableBuffer.array(), this.bufferStart)
+
+internal fun <T> Tensor<T>.copyToBufferedTensor(): BufferedTensor<T> =
+    BufferedTensor(
+        this.shape,
+        TensorLinearStructure(this.shape).indices().map(this::get).toMutableList().asMutableBuffer(), 0
+    )
+
+internal fun <T> Tensor<T>.toBufferedTensor(): BufferedTensor<T> = when (this) {
+    is BufferedTensor<T> -> this
+    is MutableBufferND<T> -> if (this.strides.strides contentEquals TensorLinearStructure(this.shape).strides)
+        BufferedTensor(this.shape, this.mutableBuffer, 0) else this.copyToBufferedTensor()
+    else -> this.copyToBufferedTensor()
+}
+
+internal val Tensor<Double>.tensor: DoubleTensor
+    get() = when (this) {
+        is DoubleTensor -> this
+        else -> this.toBufferedTensor().asTensor()
+    }
+
+internal val Tensor<Int>.tensor: IntTensor
+    get() = when (this) {
+        is IntTensor -> this
+        else -> this.toBufferedTensor().asTensor()
+    }