Added operations with external functions and elements on NDArray. Switched to kotlin 1.2.60

build.gradle

@@ -1,5 +1,5 @@
 buildscript {
-    ext.kotlin_version = '1.2.51'
+    ext.kotlin_version = '1.2.60'
 
     repositories {
         mavenCentral()

common/src/main/kotlin/scientifik/kmath/structures/NDArray.kt

@@ -14,7 +14,7 @@ class ShapeMismatchException(val expected: List<Int>, val actual: List<Int>) : R
  * @param field - operations field defined on individual array element
  * @param T the type of the element contained in NDArray
  */
-abstract class NDField<T>(val shape: List<Int>, private val field: Field<T>) : Field<NDArray<T>> {
+abstract class NDField<T>(val shape: List<Int>, val field: Field<T>) : Field<NDArray<T>> {
 
     /**
      * Create new instance of NDArray using field shape and given initializer
@@ -74,7 +74,7 @@ abstract class NDField<T>(val shape: List<Int>, private val field: Field<T>) : F
 }
 
 
-interface NDArray<T> : FieldElement<NDArray<T>, NDField<T>>, Iterable<Pair<List<Int>, T>> {
+interface NDArray<T> : FieldElement<NDArray<T>, NDField<T>> {
 
     /**
      * The list of dimensions of this NDArray
@@ -97,14 +97,14 @@ interface NDArray<T> : FieldElement<NDArray<T>, NDField<T>>, Iterable<Pair<List<
         return get(*index.toIntArray())
     }
 
-    override operator fun iterator(): Iterator<Pair<List<Int>, T>> {
+    operator fun iterator(): Iterator<Pair<List<Int>, T>> {
         return iterateIndexes(shape).map { Pair(it, this[it]) }.iterator()
     }
 
     /**
      * Generate new NDArray, using given transformation for each element
      */
-    fun transform(action: (List<Int>, T) -> T): NDArray<T> = (context as NDField<T>).produce { action(it, this[it]) }
+    fun transform(action: (List<Int>, T) -> T): NDArray<T> = context.produce { action(it, this[it]) }
 
     companion object {
         /**
@@ -125,6 +125,79 @@ interface NDArray<T> : FieldElement<NDArray<T>, NDField<T>>, Iterable<Pair<List<
     }
 }
 
+/**
+ * Element by element application of any operation on elements to the whole array. Just like in numpy
+ */
+operator fun <T> Function1<T, T>.invoke(ndArray: NDArray<T>): NDArray<T> = ndArray.transform { _, value -> this(value) }
+
+/* plus and minus */
+
+/**
+ * Summation operation for [NDArray] and single element
+ */
+operator fun <T> NDArray<T>.plus(arg: T): NDArray<T> = transform { _, value ->
+    with(context.field){
+        arg + value
+    }
+}
+
+/**
+ * Reverse sum operation
+ */
+operator fun <T> T.plus(arg: NDArray<T>): NDArray<T> = arg + this
+
+/**
+ * Subtraction operation between [NDArray] and single element
+ */
+operator fun <T> NDArray<T>.minus(arg: T): NDArray<T> = transform  { _, value ->
+    with(context.field){
+        arg - value
+    }
+}
+
+/**
+ * Reverse minus operation
+ */
+operator fun <T> T.minus(arg: NDArray<T>): NDArray<T> = arg.transform { _, value ->
+    with(arg.context.field){
+        this@minus - value
+    }
+}
+
+/* prod and div */
+
+/**
+ * Product operation for [NDArray] and single element
+ */
+operator fun <T> NDArray<T>.times(arg: T): NDArray<T> = transform { _, value ->
+    with(context.field){
+        arg * value
+    }
+}
+
+/**
+ * Reverse product operation
+ */
+operator fun <T> T.times(arg: NDArray<T>): NDArray<T> = arg * this
+
+/**
+ * Division operation between [NDArray] and single element
+ */
+operator fun <T> NDArray<T>.div(arg: T): NDArray<T> = transform  { _, value ->
+    with(context.field){
+        arg / value
+    }
+}
+
+/**
+ * Reverse division operation
+ */
+operator fun <T> T.div(arg: NDArray<T>): NDArray<T> = arg.transform { _, value ->
+    with(arg.context.field){
+        this@div/ value
+    }
+}
+
 /**
  * Create a platform-specific NDArray of doubles
  */

jvm/src/test/kotlin/scientifik/kmath/structures/RealNDFieldTest.kt

@@ -1,6 +1,7 @@
 package scientifik.kmath.structures
 
 import org.junit.Assert.assertEquals
+import kotlin.math.pow
 import kotlin.test.Test
 
 class RealNDFieldTest {
@@ -31,4 +32,11 @@ class RealNDFieldTest {
             }
         }
     }
+
+    @Test
+    fun testExternalFunction() {
+        val function: (Double) -> Double = { x -> x.pow(2) + 2 * x + 1 }
+        val result = function(array1) + 1.0
+        assertEquals(10.0, result[1,1],0.01)
+    }
 }