[WIP] wasm prototype

examples/src/main/kotlin/space/kscience/kmath/fit/qowFit.kt

@@ -10,7 +10,6 @@ import kotlinx.html.h3
 import space.kscience.kmath.data.XYErrorColumnarData
 import space.kscience.kmath.distributions.NormalDistribution
 import space.kscience.kmath.expressions.Symbol
-import space.kscience.kmath.expressions.autodiff
 import space.kscience.kmath.expressions.binding
 import space.kscience.kmath.expressions.symbol
 import space.kscience.kmath.operations.asIterable
@@ -62,7 +61,6 @@ suspend fun main() {
 
     val result = XYErrorColumnarData.of(x, y, yErr).fitWith(
         QowOptimizer,
-        Double.autodiff,
         mapOf(a to 0.9, b to 1.2, c to 2.0, e to 1.0, d to 1.0, e to 0.0),
         OptimizationParameters(a, b, c, d)
     ) { arg ->

gradle.properties

@@ -9,7 +9,7 @@ kotlin.native.ignoreDisabledTargets=true
 org.gradle.configureondemand=true
 org.gradle.jvmargs=-Xmx4096m
 
-toolsVersion=0.14.0-kotlin-1.8.10
+toolsVersion=0.14.1-kotlin-1.8.20-Beta
 
 
 org.gradle.parallel=true

kmath-core/build.gradle.kts

@@ -6,6 +6,7 @@ kscience{
     jvm()
     js()
     native()
+    wasm()
 
     dependencies {
         api(projects.kmathMemory)

kmath-memory/build.gradle.kts

@@ -8,6 +8,12 @@ kscience {
     native()
 }
 
+kotlin {
+    wasm {
+        browser()
+    }
+}
+
 readme {
     maturity = space.kscience.gradle.Maturity.DEVELOPMENT
     description = """

kmath-memory/src/wasmMain/kotlin/space/kscience/kmath/memory/WasmMemory.kt

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2018-2023 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.memory
+
+import kotlin.wasm.*
+
+@PublishedApi
+internal class WasmMemory(
+    val array: ByteArray,
+    val startOffset: Int = 0,
+    override val size: Int = array.size,
+) : Memory {
+    @Suppress("NOTHING_TO_INLINE")
+    private inline fun position(o: Int): Int = startOffset + o
+
+    override fun view(offset: Int, length: Int): Memory {
+        require(offset >= 0) { "offset shouldn't be negative: $offset" }
+        require(length >= 0) { "length shouldn't be negative: $length" }
+        require(offset + length <= size) { "Can't view memory outside the parent region." }
+        return WasmMemory(array, position(offset), length)
+    }
+
+    override fun copy(): Memory {
+        val copy = array.copyOfRange(startOffset, startOffset + size)
+        return WasmMemory(copy)
+    }
+
+    private val reader: MemoryReader = object : MemoryReader {
+        override val memory: Memory get() = this@WasmMemory
+
+        override fun readDouble(offset: Int) = array.getDoubleAt(position(offset))
+
+        override fun readFloat(offset: Int) = array.getFloatAt(position(offset))
+
+        override fun readByte(offset: Int) = array[position(offset)]
+
+        override fun readShort(offset: Int) = array.getShortAt(position(offset))
+
+        override fun readInt(offset: Int) = array.getIntAt(position(offset))
+
+        override fun readLong(offset: Int) = array.getLongAt(position(offset))
+
+        override fun release() {
+            // does nothing on JVM
+        }
+    }
+
+    override fun reader(): MemoryReader = reader
+
+    private val writer: MemoryWriter = object : MemoryWriter {
+        override val memory: Memory get() = this@WasmMemory
+
+        override fun writeDouble(offset: Int, value: Double) {
+            array.setDoubleAt(position(offset), value)
+        }
+
+        override fun writeFloat(offset: Int, value: Float) {
+            array.setFloatAt(position(offset), value)
+        }
+
+        override fun writeByte(offset: Int, value: Byte) {
+            array[position(offset)] = value
+        }
+
+        override fun writeShort(offset: Int, value: Short) {
+            array.setShortAt(position(offset), value)
+        }
+
+        override fun writeInt(offset: Int, value: Int) {
+            array.setIntAt(position(offset), value)
+        }
+
+        override fun writeLong(offset: Int, value: Long) {
+            array.setLongAt(position(offset), value)
+        }
+
+        override fun release() {
+            // does nothing on JVM
+        }
+    }
+
+    override fun writer(): MemoryWriter = writer
+}
+
+/**
+ * Wraps a [Memory] around existing [ByteArray]. This operation is unsafe since the array is not copied
+ * and could be mutated independently of the resulting [Memory].
+ */
+public actual fun Memory.Companion.wrap(array: ByteArray): Memory = WasmMemory(array)
+
+/**
+ * Allocates the most effective platform-specific memory.
+ */
+public actual fun Memory.Companion.allocate(length: Int): Memory {
+    val array = ByteArray(length)
+    return WasmMemory(array)
+}

kmath-optimization/src/commonMain/kotlin/space/kscience/kmath/optimization/XYFit.kt

@@ -12,6 +12,7 @@ import space.kscience.kmath.expressions.*
 import space.kscience.kmath.misc.FeatureSet
 import space.kscience.kmath.misc.Loggable
 import space.kscience.kmath.misc.UnstableKMathAPI
+import space.kscience.kmath.operations.DoubleField
 import space.kscience.kmath.operations.ExtendedField
 import space.kscience.kmath.operations.bindSymbol
 import kotlin.math.pow
@@ -147,6 +148,31 @@ public suspend fun <I : Any, A> XYColumnarData<Double, Double, Double>.fitWith(
     )
 }
 
+public suspend fun XYColumnarData<Double, Double, Double>.fitWith(
+    optimizer: Optimizer<Double, XYFit>,
+    startingPoint: Map<Symbol, Double>,
+    vararg features: OptimizationFeature = emptyArray(),
+    xSymbol: Symbol = Symbol.x,
+    pointToCurveDistance: PointToCurveDistance = PointToCurveDistance.byY,
+    pointWeight: PointWeight = PointWeight.byYSigma,
+    model: DSField<Double, DoubleField>.(DS<Double, DoubleField>) -> DS<Double, DoubleField>,
+): XYFit {
+    val modelExpression: DifferentiableExpression<Double> = Double.autodiff.differentiate {
+        val x = bindSymbol(xSymbol)
+        model(x)
+    }
+
+    return fitWith(
+        optimizer = optimizer,
+        modelExpression = modelExpression,
+        startingPoint = startingPoint,
+        features = features,
+        xSymbol = xSymbol,
+        pointToCurveDistance = pointToCurveDistance,
+        pointWeight = pointWeight
+    )
+}
+
 /**
  * Compute chi squared value for completed fit. Return null for incomplete fit
  */

test-utils/build.gradle.kts

@@ -6,6 +6,7 @@ kscience{
     jvm()
     js()
     native()
+    wasm()
 }
 
 kotlin.sourceSets {