From 8f5276bdcbe51658729f7828fa8ca7ba0b08f6c0 Mon Sep 17 00:00:00 2001
From: Alexander Nozik <altavir@gmail.com>
Date: Fri, 23 Nov 2018 14:08:28 +0300
Subject: [PATCH] Broaden scope of VectorSpace to include Points

---
 .../scientifik/kmath/histogram/Histogram.kt   |  13 +-
 .../kmath/histogram/PhantomHistogram.kt       |  41 ++++--
 .../scientifik/kmath/linear/LinearAlgrebra.kt | 100 +--------------
 .../kotlin/scientifik/kmath/linear/Vector.kt  | 118 ++++++++++++++++++
 .../scientifik/kmath/structures/Buffers.kt    |   2 +-
 5 files changed, 151 insertions(+), 123 deletions(-)
 create mode 100644 kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Vector.kt

diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/histogram/Histogram.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/histogram/Histogram.kt
index e143bd90d..f605f6df3 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/histogram/Histogram.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/histogram/Histogram.kt
@@ -1,6 +1,5 @@
 package scientifik.kmath.histogram
 
-import scientifik.kmath.operations.Space
 import scientifik.kmath.structures.ArrayBuffer
 import scientifik.kmath.structures.Buffer
 
@@ -55,14 +54,4 @@ fun <T: Any> MutableHistogram<T,*>.fill(sequence: Iterable<Point<T>>) = sequence
 /**
  * Pass a sequence builder into histogram
  */
-fun <T: Any> MutableHistogram<T, *>.fill(buider: suspend SequenceScope<Point<T>>.() -> Unit) = fill(sequence(buider).asIterable())
-
-/**
- * A space to perform arithmetic operations on histograms
- */
-interface HistogramSpace<T: Any, B : Bin<T>, H : Histogram<T,B>> : Space<H> {
-    /**
-     * Rules for performing operations on bins
-     */
-    val binSpace: Space<Bin<T>>
-}
\ No newline at end of file
+fun <T: Any> MutableHistogram<T, *>.fill(buider: suspend SequenceScope<Point<T>>.() -> Unit) = fill(sequence(buider).asIterable())
\ No newline at end of file
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/histogram/PhantomHistogram.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/histogram/PhantomHistogram.kt
index 0bd5de0e2..041eccfe2 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/histogram/PhantomHistogram.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/histogram/PhantomHistogram.kt
@@ -1,23 +1,38 @@
 package scientifik.kmath.histogram
 
-import scientifik.kmath.linear.RealVector
+import scientifik.kmath.linear.Vector
+import scientifik.kmath.operations.Space
 import scientifik.kmath.structures.NDStructure
 
-class BinTemplate(val center: RealVector, val sizes: RealVector) {
-    fun contains(vector: Point<out Double>): Boolean {
+class BinTemplate<T : Comparable<T>>(val center: Vector<T>, val sizes: Vector<T>) {
+    fun contains(vector: Point<out T>): Boolean {
         if (vector.size != center.size) error("Dimension mismatch for input vector. Expected ${center.size}, but found ${vector.size}")
-        return vector.asSequence().mapIndexed { i, value -> value in (center[i] - sizes[i] / 2)..(center[i] + sizes[i] / 2) }.all { it }
+        val upper = center + sizes/2.0
+        val lower = center - sizes/2.0
+        return vector.asSequence().mapIndexed { i, value ->
+            value in lower[i]..upper[i]
+        }.all { it }
     }
 }
 
-class PhantomBin(val template: BinTemplate, override val value: Number) : Bin<Double> {
+/**
+ * A space to perform arithmetic operations on histograms
+ */
+interface HistogramSpace<T : Any, B : Bin<T>, H : Histogram<T, B>> : Space<H> {
+    /**
+     * Rules for performing operations on bins
+     */
+    val binSpace: Space<Bin<T>>
+}
 
-    override fun contains(vector: Point<out Double>): Boolean = template.contains(vector)
+class PhantomBin<T : Comparable<T>>(val template: BinTemplate<T>, override val value: Number) : Bin<T> {
+
+    override fun contains(vector: Point<out T>): Boolean = template.contains(vector)
 
     override val dimension: Int
         get() = template.center.size
 
-    override val center: Point<Double>
+    override val center: Point<T>
         get() = template.center
 
 }
@@ -26,19 +41,19 @@ class PhantomBin(val template: BinTemplate, override val value: Number) : Bin<Do
  * Immutable histogram with explicit structure for content and additional external bin description.
  * Bin search is slow, but full histogram algebra is supported.
  */
-class PhantomHistogram(
-        val bins: Map<BinTemplate, IntArray>,
+class PhantomHistogram<T : Comparable<T>>(
+        val bins: Map<BinTemplate<T>, IntArray>,
         val data: NDStructure<Double>
-) : Histogram<Double, PhantomBin> {
+) : Histogram<T, PhantomBin<T>> {
 
     override val dimension: Int
         get() = data.dimension
 
-    override fun iterator(): Iterator<PhantomBin> {
-        return bins.asSequence().map {entry-> PhantomBin(entry.key,data[entry.value]) }.iterator()
+    override fun iterator(): Iterator<PhantomBin<T>> {
+        return bins.asSequence().map { entry -> PhantomBin(entry.key, data[entry.value]) }.iterator()
     }
 
-    override fun get(point: Point<out Double>): PhantomBin? {
+    override fun get(point: Point<out T>): PhantomBin<T>? {
         val template = bins.keys.find { it.contains(point) }
         return template?.let { PhantomBin(it, data[bins[it]!!]) }
     }
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/LinearAlgrebra.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/LinearAlgrebra.kt
index 62852ff5d..9e8692b42 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/LinearAlgrebra.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/LinearAlgrebra.kt
@@ -1,7 +1,9 @@
 package scientifik.kmath.linear
 
 import scientifik.kmath.operations.*
-import scientifik.kmath.structures.*
+import scientifik.kmath.structures.ExtendedNDField
+import scientifik.kmath.structures.GenericNDField
+import scientifik.kmath.structures.NDField
 
 /**
  * The space for linear elements. Supports scalar product alongside with standard linear operations.
@@ -139,49 +141,7 @@ interface Matrix<T : Any> : SpaceElement<Matrix<T>, MatrixSpace<T>> {
 }
 
 
-/**
- * A linear space for vectors
- */
-abstract class VectorSpace<T : Any>(val size: Int, val field: Field<T>) : Space<Vector<T>> {
 
-    abstract fun produce(initializer: (Int) -> T): Vector<T>
-
-    override val zero: Vector<T> by lazy { produce { field.zero } }
-
-    override fun add(a: Vector<T>, b: Vector<T>): Vector<T> = produce { with(field) { a[it] + b[it] } }
-
-    override fun multiply(a: Vector<T>, k: Double): Vector<T> = produce { with(field) { a[it] * k } }
-}
-
-
-interface Vector<T : Any> : SpaceElement<Vector<T>, VectorSpace<T>>, Buffer<T>, Iterable<T> {
-    override val size: Int get() = context.size
-
-    companion object {
-        /**
-         * Create vector with custom field
-         */
-        fun <T : Any> of(size: Int, field: Field<T>, initializer: (Int) -> T) =
-                ArrayVector(ArrayVectorSpace(size, field), initializer)
-
-        /**
-         * Create vector of [Double]
-         */
-        fun ofReal(size: Int, initializer: (Int) -> Double) =
-                ArrayVector(ArrayVectorSpace(size, DoubleField, realNDFieldFactory), initializer)
-
-        fun ofReal(vararg point: Double) = point.toVector()
-
-        fun equals(v1: Vector<*>, v2: Vector<*>): Boolean {
-            if (v1 === v2) return true
-            if (v1.context != v2.context) return false
-            for (i in 0 until v2.size) {
-                if (v1[i] != v2[i]) return false
-            }
-            return true
-        }
-    }
-}
 
 typealias NDFieldFactory<T> = (IntArray) -> NDField<T>
 
@@ -210,61 +170,7 @@ class ArrayMatrixSpace<T : Any>(
     }
 }
 
-class ArrayVectorSpace<T : Any>(
-        size: Int,
-        field: Field<T>,
-        val ndFactory: NDFieldFactory<T> = genericNDFieldFactory(field)
-) : VectorSpace<T>(size, field) {
-    val ndField by lazy {
-        ndFactory(intArrayOf(size))
-    }
 
-    override fun produce(initializer: (Int) -> T): Vector<T> = ArrayVector(this, initializer)
-}
-
-/**
- * Member of [ArrayMatrixSpace] which wraps 2-D array
- */
-class ArrayMatrix<T : Any> internal constructor(override val context: ArrayMatrixSpace<T>, val element: NDElement<T>) : Matrix<T> {
-
-    constructor(context: ArrayMatrixSpace<T>, initializer: (Int, Int) -> T) : this(context, context.ndField.produce { list -> initializer(list[0], list[1]) })
-
-    override val rows: Int get() = context.rows
-
-    override val columns: Int get() = context.columns
-
-    override fun get(i: Int, j: Int): T {
-        return element[i, j]
-    }
-
-    override val self: ArrayMatrix<T> get() = this
-}
-
-
-class ArrayVector<T : Any> internal constructor(override val context: ArrayVectorSpace<T>, val element: NDElement<T>) : Vector<T> {
-
-    constructor(context: ArrayVectorSpace<T>, initializer: (Int) -> T) : this(context, context.ndField.produce { list -> initializer(list[0]) })
-
-    init {
-        if (context.size != element.shape[0]) {
-            error("Array dimension mismatch")
-        }
-    }
-
-    override fun get(index: Int): T {
-        return element[index]
-    }
-
-    override val self: ArrayVector<T> get() = this
-
-    override fun iterator(): Iterator<T> = (0 until size).map { element[it] }.iterator()
-
-    override fun copy(): ArrayVector<T> = ArrayVector(context, element)
-
-    override fun toString(): String = this.joinToString(prefix = "[", postfix = "]", separator = ", ") { it.toString() }
-}
-
-typealias RealVector = Vector<Double>
 
 /**
  * A group of methods to resolve equation A dot X = B, where A and B are matrices or vectors
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Vector.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Vector.kt
new file mode 100644
index 000000000..70480542f
--- /dev/null
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Vector.kt
@@ -0,0 +1,118 @@
+package scientifik.kmath.linear
+
+import scientifik.kmath.histogram.Point
+import scientifik.kmath.operations.DoubleField
+import scientifik.kmath.operations.Field
+import scientifik.kmath.operations.Space
+import scientifik.kmath.operations.SpaceElement
+import scientifik.kmath.structures.NDElement
+import scientifik.kmath.structures.get
+
+/**
+ * A linear space for vectors.
+ * Could be used on any point-like structure
+ */
+abstract class VectorSpace<T : Any>(val size: Int, val field: Field<T>) : Space<Point<T>> {
+
+    abstract fun produce(initializer: (Int) -> T): Vector<T>
+
+    override val zero: Vector<T> by lazy { produce { field.zero } }
+
+    override fun add(a: Point<T>, b: Point<T>): Vector<T> = produce { with(field) { a[it] + b[it] } }
+
+    override fun multiply(a: Point<T>, k: Double): Vector<T> = produce { with(field) { a[it] * k } }
+}
+
+
+/**
+ * A point coupled to the linear space
+ */
+interface Vector<T : Any> : SpaceElement<Point<T>, VectorSpace<T>>, Point<T>, Iterable<T> {
+    override val size: Int get() = context.size
+
+    override operator fun plus(b: Point<T>): Vector<T> = context.add(self, b)
+    override operator fun minus(b: Point<T>): Vector<T> = context.add(self, context.multiply(b, -1.0))
+    override operator fun times(k: Number): Vector<T> = context.multiply(self, k.toDouble())
+    override operator fun div(k: Number): Vector<T> = context.multiply(self, 1.0 / k.toDouble())
+
+    companion object {
+        /**
+         * Create vector with custom field
+         */
+        fun <T : Any> of(size: Int, field: Field<T>, initializer: (Int) -> T) =
+                ArrayVector(ArrayVectorSpace(size, field), initializer)
+
+        /**
+         * Create vector of [Double]
+         */
+        fun ofReal(size: Int, initializer: (Int) -> Double) =
+                ArrayVector(ArrayVectorSpace(size, DoubleField, realNDFieldFactory), initializer)
+
+        fun ofReal(vararg point: Double) = point.toVector()
+
+        fun equals(v1: Vector<*>, v2: Vector<*>): Boolean {
+            if (v1 === v2) return true
+            if (v1.context != v2.context) return false
+            for (i in 0 until v2.size) {
+                if (v1[i] != v2[i]) return false
+            }
+            return true
+        }
+    }
+}
+
+class ArrayVectorSpace<T : Any>(
+        size: Int,
+        field: Field<T>,
+        val ndFactory: NDFieldFactory<T> = genericNDFieldFactory(field)
+) : VectorSpace<T>(size, field) {
+    val ndField by lazy {
+        ndFactory(intArrayOf(size))
+    }
+
+    override fun produce(initializer: (Int) -> T): Vector<T> = ArrayVector(this, initializer)
+}
+
+/**
+ * Member of [ArrayMatrixSpace] which wraps 2-D array
+ */
+class ArrayMatrix<T : Any> internal constructor(override val context: ArrayMatrixSpace<T>, val element: NDElement<T>) : Matrix<T> {
+
+    constructor(context: ArrayMatrixSpace<T>, initializer: (Int, Int) -> T) : this(context, context.ndField.produce { list -> initializer(list[0], list[1]) })
+
+    override val rows: Int get() = context.rows
+
+    override val columns: Int get() = context.columns
+
+    override fun get(i: Int, j: Int): T {
+        return element[i, j]
+    }
+
+    override val self: ArrayMatrix<T> get() = this
+}
+
+
+class ArrayVector<T : Any> internal constructor(override val context: VectorSpace<T>, val element: NDElement<T>) : Vector<T> {
+
+    constructor(context: ArrayVectorSpace<T>, initializer: (Int) -> T) : this(context, context.ndField.produce { list -> initializer(list[0]) })
+
+    init {
+        if (context.size != element.shape[0]) {
+            error("Array dimension mismatch")
+        }
+    }
+
+    override fun get(index: Int): T {
+        return element[index]
+    }
+
+    override val self: ArrayVector<T> get() = this
+
+    override fun iterator(): Iterator<T> = (0 until size).map { element[it] }.iterator()
+
+    override fun copy(): ArrayVector<T> = ArrayVector(context, element)
+
+    override fun toString(): String = this.joinToString(prefix = "[", postfix = "]", separator = ", ") { it.toString() }
+}
+
+typealias RealVector = Vector<Double>
\ No newline at end of file
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/Buffers.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/Buffers.kt
index b68072332..052f9caa4 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/Buffers.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/Buffers.kt
@@ -2,7 +2,7 @@ package scientifik.kmath.structures
 
 
 /**
- * A generic linear buffer for both primitives and objects
+ * A generic random access structure for both primitives and objects
  */
 interface Buffer<T> : Iterable<T> {