From 037735c210e437a4ecf02fbbe24fb37132c6ef8a Mon Sep 17 00:00:00 2001
From: Alexander Nozik <altavir@gmail.com>
Date: Sun, 13 Jan 2019 10:42:53 +0300
Subject: [PATCH] Replaced Double in algebra by numbers, DiffExpressions

---
 kmath-commons/build.gradle.kts                |  15 +++
 .../kmath/expressions/DiffExpression.kt       | 106 ++++++++++++++++++
 .../kmath/expressions/AutoDiffTest.kt         |  31 +++++
 .../kmath/expressions/Expression.kt           |   9 +-
 .../kotlin/scientifik/kmath/linear/Matrix.kt  |  25 ++---
 .../kotlin/scientifik/kmath/linear/Vector.kt  |   2 +-
 .../scientifik/kmath/operations/Algebra.kt    |   4 +-
 .../scientifik/kmath/operations/Complex.kt    |   2 +-
 .../kmath/operations/NumberAlgebra.kt         |  32 +++---
 .../kmath/operations/OptionalOperations.kt    |   2 +-
 .../scientifik/kmath/structures/NDAlgebra.kt  |   2 +-
 .../kmath/structures/RealNDField.kt           |   2 +-
 settings.gradle.kts                           |   1 +
 13 files changed, 192 insertions(+), 41 deletions(-)
 create mode 100644 kmath-commons/build.gradle.kts
 create mode 100644 kmath-commons/src/main/kotlin/scientifik/kmath/expressions/DiffExpression.kt
 create mode 100644 kmath-commons/src/test/kotlin/scientifik/kmath/expressions/AutoDiffTest.kt

diff --git a/kmath-commons/build.gradle.kts b/kmath-commons/build.gradle.kts
new file mode 100644
index 000000000..7b859a2b0
--- /dev/null
+++ b/kmath-commons/build.gradle.kts
@@ -0,0 +1,15 @@
+plugins {
+    kotlin("jvm")
+}
+
+dependencies {
+    api(project(":kmath-core"))
+    api("org.apache.commons:commons-math3:3.6.1")
+    testImplementation("org.jetbrains.kotlin:kotlin-test")
+    testImplementation("org.jetbrains.kotlin:kotlin-test-junit")
+}
+
+//dependencies {
+////    compile(project(":kmath-core"))
+////    //compile project(":kmath-coroutines")
+////}
\ No newline at end of file
diff --git a/kmath-commons/src/main/kotlin/scientifik/kmath/expressions/DiffExpression.kt b/kmath-commons/src/main/kotlin/scientifik/kmath/expressions/DiffExpression.kt
new file mode 100644
index 000000000..4d5ea1b94
--- /dev/null
+++ b/kmath-commons/src/main/kotlin/scientifik/kmath/expressions/DiffExpression.kt
@@ -0,0 +1,106 @@
+package scientifik.kmath.expressions
+
+import org.apache.commons.math3.analysis.differentiation.DerivativeStructure
+import scientifik.kmath.operations.ExtendedField
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KProperty
+
+/**
+ * A field wrapping commons-math derivative structures
+ */
+class DerivativeStructureField(val order: Int, val parameters: Map<String, Double>) :
+    ExtendedField<DerivativeStructure> {
+
+    override val zero: DerivativeStructure by lazy { DerivativeStructure(order, parameters.size) }
+
+    override val one: DerivativeStructure by lazy { DerivativeStructure(order, parameters.size, 1.0) }
+
+    private val variables: Map<String, DerivativeStructure> = parameters.mapValues { (key, value) ->
+        DerivativeStructure(parameters.size, order, parameters.keys.indexOf(key), value)
+    }
+
+    val variable = object : ReadOnlyProperty<Any?, DerivativeStructure> {
+        override fun getValue(thisRef: Any?, property: KProperty<*>): DerivativeStructure {
+            return variables[property.name] ?: error("A variable with name ${property.name} does not exist")
+        }
+    }
+
+    fun variable(name: String): DerivativeStructure =
+        variables[name] ?: error("A variable with name ${name} does not exist")
+
+
+    fun Number.const() = DerivativeStructure(order, parameters.size, toDouble())
+
+    fun DerivativeStructure.deriv(parName: String, order: Int = 1): Double {
+        return deriv(mapOf(parName to order))
+    }
+
+    fun DerivativeStructure.deriv(orders: Map<String, Int>): Double {
+        return getPartialDerivative(*parameters.keys.map { orders[it] ?: 0 }.toIntArray())
+    }
+
+    fun DerivativeStructure.deriv(vararg orders: Pair<String, Int>): Double = deriv(mapOf(*orders))
+
+    override fun add(a: DerivativeStructure, b: DerivativeStructure): DerivativeStructure = a.add(b)
+
+    override fun multiply(a: DerivativeStructure, k: Number): DerivativeStructure = when (k) {
+        is Double -> a.multiply(k)
+        is Int -> a.multiply(k)
+        else -> a.multiply(k.toDouble())
+    }
+
+    override fun multiply(a: DerivativeStructure, b: DerivativeStructure): DerivativeStructure = a.multiply(b)
+
+    override fun divide(a: DerivativeStructure, b: DerivativeStructure): DerivativeStructure = a.divide(b)
+
+    override fun sin(arg: DerivativeStructure): DerivativeStructure = arg.sin()
+
+    override fun cos(arg: DerivativeStructure): DerivativeStructure = arg.cos()
+
+    override fun power(arg: DerivativeStructure, pow: Number): DerivativeStructure = when (pow) {
+        is Double -> arg.pow(pow)
+        is Int -> arg.pow(pow)
+        else -> arg.pow(pow.toDouble())
+    }
+
+    fun power(arg: DerivativeStructure, pow: DerivativeStructure): DerivativeStructure = arg.pow(pow)
+
+    override fun exp(arg: DerivativeStructure): DerivativeStructure = arg.exp()
+
+    override fun ln(arg: DerivativeStructure): DerivativeStructure = arg.log()
+
+    operator fun DerivativeStructure.plus(n: Number): DerivativeStructure = add(n.toDouble())
+    operator fun DerivativeStructure.minus(n: Number): DerivativeStructure = subtract(n.toDouble())
+    operator fun Number.plus(s: DerivativeStructure) = s + this
+    operator fun Number.minus(s: DerivativeStructure) = s - this
+}
+
+/**
+ * A constructs that creates a derivative structure with required order on-demand
+ */
+class DiffExpression(val function: DerivativeStructureField.() -> DerivativeStructure) : Expression<Double> {
+    override fun invoke(arguments: Map<String, Double>): Double = DerivativeStructureField(0, arguments)
+        .run(function).value
+
+    /**
+     * Get the derivative expression with given orders
+     * TODO make result [DiffExpression]
+     */
+    fun derivative(orders: Map<String, Int>): Expression<Double> {
+        return object : Expression<Double> {
+            override fun invoke(arguments: Map<String, Double>): Double =
+                DerivativeStructureField(orders.values.max() ?: 0, arguments)
+                    .run {
+                        function().deriv(orders)
+                    }
+        }
+    }
+
+    //TODO add gradient and maybe other vector operators
+}
+
+fun DiffExpression.derivative(vararg orders: Pair<String, Int>) = derivative(mapOf(*orders))
+fun DiffExpression.derivative(name: String) = derivative(name to 1)
+
+
+
diff --git a/kmath-commons/src/test/kotlin/scientifik/kmath/expressions/AutoDiffTest.kt b/kmath-commons/src/test/kotlin/scientifik/kmath/expressions/AutoDiffTest.kt
new file mode 100644
index 000000000..2695bb918
--- /dev/null
+++ b/kmath-commons/src/test/kotlin/scientifik/kmath/expressions/AutoDiffTest.kt
@@ -0,0 +1,31 @@
+package scientifik.kmath.expressions
+
+import org.junit.Test
+import kotlin.test.assertEquals
+
+inline fun <R> diff(order: Int, vararg parameters: Pair<String, Double>, block: DerivativeStructureField.() -> R) =
+    DerivativeStructureField(order, mapOf(*parameters)).run(block)
+
+class AutoDiffTest {
+    @Test
+    fun derivativeStructureFieldTest() {
+        val res = diff(3, "x" to 1.0, "y" to 1.0) {
+            val x by variable
+            val y = variable("y")
+            val z = x * (-sin(x * y) + y)
+            z.deriv("x")
+        }
+    }
+
+    @Test
+    fun autoDifTest() {
+        val f = DiffExpression {
+            val x by variable
+            val y by variable
+            x.pow(2) + 2 * x * y + y.pow(2) + 1
+        }
+
+        assertEquals(10.0, f("x" to 1.0, "y" to 2.0))
+        assertEquals(6.0, f.derivative("x")("x" to 1.0, "y" to 2.0))
+    }
+}
\ No newline at end of file
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/expressions/Expression.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/expressions/Expression.kt
index f7ae09d02..2f54ae1b2 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/expressions/Expression.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/expressions/Expression.kt
@@ -1,6 +1,7 @@
 package scientifik.kmath.expressions
 
 import scientifik.kmath.operations.Field
+import scientifik.kmath.operations.Ring
 import scientifik.kmath.operations.Space
 
 
@@ -18,7 +19,7 @@ interface ExpressionContext<T> {
 
 internal class VariableExpression<T>(val name: String, val default: T? = null) : Expression<T> {
     override fun invoke(arguments: Map<String, T>): T =
-            arguments[name] ?: default ?: error("Parameter not found: $name")
+        arguments[name] ?: default ?: error("Parameter not found: $name")
 }
 
 internal class ConstantExpression<T>(val value: T) : Expression<T> {
@@ -30,13 +31,13 @@ internal class SumExpression<T>(val context: Space<T>, val first: Expression<T>,
     override fun invoke(arguments: Map<String, T>): T = context.add(first.invoke(arguments), second.invoke(arguments))
 }
 
-internal class ProductExpression<T>(val context: Field<T>, val first: Expression<T>, val second: Expression<T>) :
+internal class ProductExpression<T>(val context: Ring<T>, val first: Expression<T>, val second: Expression<T>) :
     Expression<T> {
     override fun invoke(arguments: Map<String, T>): T =
         context.multiply(first.invoke(arguments), second.invoke(arguments))
 }
 
-internal class ConstProductExpession<T>(val context: Field<T>, val expr: Expression<T>, val const: Double) :
+internal class ConstProductExpession<T>(val context: Space<T>, val expr: Expression<T>, val const: Number) :
     Expression<T> {
     override fun invoke(arguments: Map<String, T>): T = context.multiply(expr.invoke(arguments), const)
 }
@@ -58,7 +59,7 @@ class ExpressionField<T>(val field: Field<T>) : Field<Expression<T>>, Expression
 
     override fun add(a: Expression<T>, b: Expression<T>): Expression<T> = SumExpression(field, a, b)
 
-    override fun multiply(a: Expression<T>, k: Double): Expression<T> = ConstProductExpession(field, a, k)
+    override fun multiply(a: Expression<T>, k: Number): Expression<T> = ConstProductExpession(field, a, k)
 
     override fun multiply(a: Expression<T>, b: Expression<T>): Expression<T> = ProductExpression(field, a, b)
 
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Matrix.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Matrix.kt
index 35ad86379..0edf748e6 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Matrix.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Matrix.kt
@@ -6,7 +6,6 @@ import scientifik.kmath.operations.Space
 import scientifik.kmath.operations.SpaceElement
 import scientifik.kmath.structures.*
 import scientifik.kmath.structures.Buffer.Companion.DoubleBufferFactory
-import scientifik.kmath.structures.Buffer.Companion.auto
 import scientifik.kmath.structures.Buffer.Companion.boxing
 
 
@@ -19,8 +18,6 @@ interface MatrixSpace<T : Any, R : Ring<T>> : Space<Matrix<T, R>> {
     val rowNum: Int
     val colNum: Int
 
-    val shape get() = intArrayOf(rowNum, colNum)
-
     /**
      * Produce a matrix with this context and given dimensions
      */
@@ -38,7 +35,7 @@ interface MatrixSpace<T : Any, R : Ring<T>> : Space<Matrix<T, R>> {
     override fun add(a: Matrix<T, R>, b: Matrix<T, R>): Matrix<T, R> =
         produce(rowNum, colNum) { i, j -> ring.run { a[i, j] + b[i, j] } }
 
-    override fun multiply(a: Matrix<T, R>, k: Double): Matrix<T, R> =
+    override fun multiply(a: Matrix<T, R>, k: Number): Matrix<T, R> =
         produce(rowNum, colNum) { i, j -> ring.run { a[i, j] * k } }
 
     companion object {
@@ -61,8 +58,8 @@ interface MatrixSpace<T : Any, R : Ring<T>> : Space<Matrix<T, R>> {
         /**
          * Automatic buffered matrix, unboxed if it is possible
          */
-        inline fun <reified T : Any, R : Ring<T>> smart(rows: Int, columns: Int, ring: R): MatrixSpace<T, R> =
-            buffered(rows, columns, ring, ::auto)
+        inline fun <reified T : Any, R : Ring<T>> auto(rows: Int, columns: Int, ring: R): MatrixSpace<T, R> =
+            buffered(rows, columns, ring, Buffer.Companion::auto)
     }
 }
 
@@ -80,21 +77,19 @@ interface Matrix<T : Any, R : Ring<T>> : NDStructure<T>, SpaceElement<Matrix<T,
 
     override fun get(index: IntArray): T = get(index[0], index[1])
 
-    override val shape: IntArray get() = context.shape
-
     val numRows get() = context.rowNum
     val numCols get() = context.colNum
 
     //TODO replace by lazy buffers
-    val rows: List<Point<T>>
-        get() = (0 until numRows).map { i ->
+    val rows: Point<Point<T>>
+        get() = ListBuffer((0 until numRows).map { i ->
             context.point(numCols) { j -> get(i, j) }
-        }
+        })
 
-    val columns: List<Point<T>>
-        get() = (0 until numCols).map { j ->
+    val columns: Point<Point<T>>
+        get() = ListBuffer((0 until numCols).map { j ->
             context.point(numRows) { i -> get(i, j) }
-        }
+        })
 
     val features: Set<MatrixFeature>
 
@@ -134,7 +129,7 @@ data class StructureMatrixSpace<T : Any, R : Ring<T>>(
     private val bufferFactory: BufferFactory<T>
 ) : MatrixSpace<T, R> {
 
-    override val shape: IntArray = intArrayOf(rowNum, colNum)
+    val shape: IntArray = intArrayOf(rowNum, colNum)
 
     private val strides = DefaultStrides(shape)
 
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Vector.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Vector.kt
index a673c0197..a7373f647 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Vector.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Vector.kt
@@ -30,7 +30,7 @@ interface VectorSpace<T : Any, S : Space<T>> : Space<Point<T>> {
 
     override fun add(a: Point<T>, b: Point<T>): Point<T> = produce { with(space) { a[it] + b[it] } }
 
-    override fun multiply(a: Point<T>, k: Double): Point<T> = produce { with(space) { a[it] * k } }
+    override fun multiply(a: Point<T>, k: Number): Point<T> = produce { with(space) { a[it] * k } }
 
     //TODO add basis
 
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/Algebra.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/Algebra.kt
index d77df4b7f..1534f4c82 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/Algebra.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/Algebra.kt
@@ -7,7 +7,7 @@ package scientifik.kmath.operations
  * One must note that in some cases context is a singleton class, but in some cases it
  * works as a context for operations inside it.
  *
- * TODO do we need commutative context?
+ * TODO do we need non-commutative context?
  */
 interface Space<T> {
     /**
@@ -23,7 +23,7 @@ interface Space<T> {
     /**
      * Multiplication operation for context element and real number
      */
-    fun multiply(a: T, k: Double): T
+    fun multiply(a: T, k: Number): T
 
     //Operation to be performed in this context
     operator fun T.unaryMinus(): T = multiply(this, -1.0)
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/Complex.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/Complex.kt
index 107bb2f24..20e8f47ec 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/Complex.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/Complex.kt
@@ -12,7 +12,7 @@ object ComplexField : Field<Complex> {
 
     override fun add(a: Complex, b: Complex): Complex = Complex(a.re + b.re, a.im + b.im)
 
-    override fun multiply(a: Complex, k: Double): Complex = Complex(a.re * k, a.im * k)
+    override fun multiply(a: Complex, k: Number): Complex = Complex(a.re * k.toDouble(), a.im * k.toDouble())
 
     override fun multiply(a: Complex, b: Complex): Complex =
         Complex(a.re * b.re - a.im * b.im, a.re * b.im + a.im * b.re)
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/NumberAlgebra.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/NumberAlgebra.kt
index 953f2e326..a57688ad8 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/NumberAlgebra.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/NumberAlgebra.kt
@@ -34,21 +34,23 @@ inline class Real(val value: Double) : FieldElement<Double, Real, RealField> {
 object RealField : ExtendedField<Double>, Norm<Double, Double> {
     override val zero: Double = 0.0
     override fun add(a: Double, b: Double): Double = a + b
-    override fun multiply(a: Double, @Suppress("PARAMETER_NAME_CHANGED_ON_OVERRIDE") b: Double): Double = a * b
+    override fun multiply(a: Double, b: Double): Double = a * b
+    override fun multiply(a: Double, k: Number): Double = a * k.toDouble()
+
     override val one: Double = 1.0
     override fun divide(a: Double, b: Double): Double = a / b
 
     override fun sin(arg: Double): Double = kotlin.math.sin(arg)
     override fun cos(arg: Double): Double = kotlin.math.cos(arg)
 
-    override fun power(arg: Double, pow: Double): Double = arg.pow(pow)
+    override fun power(arg: Double, pow: Number): Double = arg.pow(pow.toDouble())
 
     override fun exp(arg: Double): Double = kotlin.math.exp(arg)
     override fun ln(arg: Double): Double = kotlin.math.ln(arg)
 
     override fun norm(arg: Double): Double = kotlin.math.abs(arg)
 
-    override fun Double.unaryMinus(): Double  = -this
+    override fun Double.unaryMinus(): Double = -this
 
     override fun Double.minus(b: Double): Double = this - b
 }
@@ -56,51 +58,51 @@ object RealField : ExtendedField<Double>, Norm<Double, Double> {
 /**
  * A field for [Int] without boxing. Does not produce corresponding field element
  */
-object IntRing : Ring<Int>, Norm<Int,Int> {
+object IntRing : Ring<Int>, Norm<Int, Int> {
     override val zero: Int = 0
     override fun add(a: Int, b: Int): Int = a + b
     override fun multiply(a: Int, b: Int): Int = a * b
-    override fun multiply(a: Int, k: Double): Int = (k * a).toInt()
+    override fun multiply(a: Int, k: Number): Int = (k * a)
     override val one: Int = 1
 
-    override fun norm(arg: Int): Int  = arg
+    override fun norm(arg: Int): Int = arg
 }
 
 /**
  * A field for [Short] without boxing. Does not produce appropriate field element
  */
-object ShortRing : Ring<Short>, Norm<Short,Short>{
+object ShortRing : Ring<Short>, Norm<Short, Short> {
     override val zero: Short = 0
     override fun add(a: Short, b: Short): Short = (a + b).toShort()
     override fun multiply(a: Short, b: Short): Short = (a * b).toShort()
-    override fun multiply(a: Short, k: Double): Short = (a * k).toShort()
+    override fun multiply(a: Short, k: Number): Short = (a * k)
     override val one: Short = 1
 
-    override fun norm(arg: Short): Short  = arg
+    override fun norm(arg: Short): Short = arg
 }
 
 /**
  * A field for [Byte] values
  */
-object ByteRing : Ring<Byte>, Norm<Byte,Byte> {
+object ByteRing : Ring<Byte>, Norm<Byte, Byte> {
     override val zero: Byte = 0
     override fun add(a: Byte, b: Byte): Byte = (a + b).toByte()
     override fun multiply(a: Byte, b: Byte): Byte = (a * b).toByte()
-    override fun multiply(a: Byte, k: Double): Byte = (a * k).toByte()
+    override fun multiply(a: Byte, k: Number): Byte = (a * k)
     override val one: Byte = 1
 
-    override fun norm(arg: Byte): Byte  = arg
+    override fun norm(arg: Byte): Byte = arg
 }
 
 /**
  * A field for [Long] values
  */
-object LongRing : Ring<Long>, Norm<Long,Long> {
+object LongRing : Ring<Long>, Norm<Long, Long> {
     override val zero: Long = 0
     override fun add(a: Long, b: Long): Long = (a + b)
     override fun multiply(a: Long, b: Long): Long = (a * b)
-    override fun multiply(a: Long, k: Double): Long = (a * k).toLong()
+    override fun multiply(a: Long, k: Number): Long = (a * k)
     override val one: Long = 1
 
-    override fun norm(arg: Long): Long  = arg
+    override fun norm(arg: Long): Long = arg
 }
\ No newline at end of file
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/OptionalOperations.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/OptionalOperations.kt
index 7a7866966..66ca205a1 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/OptionalOperations.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/OptionalOperations.kt
@@ -30,7 +30,7 @@ fun <T : MathElement<out TrigonometricOperations<T>>> ctg(arg: T): T = arg.conte
  * A context extension to include power operations like square roots, etc
  */
 interface PowerOperations<T> {
-    fun power(arg: T, pow: Double): T
+    fun power(arg: T, pow: Number): T
     fun sqrt(arg: T) = power(arg, 0.5)
 }
 
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/NDAlgebra.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/NDAlgebra.kt
index 63818afcd..097d52723 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/NDAlgebra.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/NDAlgebra.kt
@@ -70,7 +70,7 @@ interface NDSpace<T, S : Space<T>, N : NDStructure<T>> : Space<N>, NDAlgebra<T,
     /**
      * Multiply all elements by constant
      */
-    override fun multiply(a: N, k: Double): N = map(a) { multiply(it, k) }
+    override fun multiply(a: N, k: Number): N = map(a) { multiply(it, k) }
 
     operator fun N.plus(arg: T) = map(this) { value -> add(arg, value) }
     operator fun N.minus(arg: T) = map(this) { value -> add(arg, -value) }
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/RealNDField.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/RealNDField.kt
index 62c2338c6..bc5832e1c 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/RealNDField.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/structures/RealNDField.kt
@@ -65,7 +65,7 @@ class RealNDField(override val shape: IntArray) :
     override fun NDBuffer<Double>.toElement(): FieldElement<NDBuffer<Double>, *, out BufferedNDField<Double, RealField>> =
         BufferedNDFieldElement(this@RealNDField, buffer)
 
-    override fun power(arg: NDBuffer<Double>, pow: Double) = map(arg) { power(it, pow) }
+    override fun power(arg: NDBuffer<Double>, pow: Number) = map(arg) { power(it, pow) }
 
     override fun exp(arg: NDBuffer<Double>) = map(arg) { exp(it) }
 
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 3a8aef730..fa0bb49a0 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -12,5 +12,6 @@ include(
     ":kmath-core",
     ":kmath-io",
     ":kmath-coroutines",
+    ":kmath-commons",
     ":benchmarks"
 )