From 287e2aeba2ba274508f42f1ab0a839ed69861bc1 Mon Sep 17 00:00:00 2001
From: Roland Grinis <roland.grinis@grinisrit.com>
Date: Fri, 23 Apr 2021 14:22:52 +0100
Subject: [PATCH] div operator

---
 .../kmath/tensors/api/TensorPartialDivisionAlgebra.kt  |  1 +
 .../kmath/tensors/core/algebras/DoubleTensorAlgebra.kt | 10 ++++++----
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/api/TensorPartialDivisionAlgebra.kt b/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/api/TensorPartialDivisionAlgebra.kt
index 075e86e61..4dab3dd07 100644
--- a/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/api/TensorPartialDivisionAlgebra.kt
+++ b/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/api/TensorPartialDivisionAlgebra.kt
@@ -8,6 +8,7 @@ package space.kscience.kmath.tensors.api
 // https://proofwiki.org/wiki/Definition:Division_Algebra
 public interface TensorPartialDivisionAlgebra<T> :
     TensorAlgebra<T> {
+    public operator fun T.div(other: TensorStructure<T>): TensorStructure<T>
     public operator fun TensorStructure<T>.div(value: T): TensorStructure<T>
     public operator fun TensorStructure<T>.div(other: TensorStructure<T>): TensorStructure<T>
     public operator fun TensorStructure<T>.divAssign(value: T)
diff --git a/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/algebras/DoubleTensorAlgebra.kt b/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/algebras/DoubleTensorAlgebra.kt
index 651db2c21..b61a484d0 100644
--- a/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/algebras/DoubleTensorAlgebra.kt
+++ b/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/algebras/DoubleTensorAlgebra.kt
@@ -178,13 +178,15 @@ public open class DoubleTensorAlgebra : TensorPartialDivisionAlgebra<Double> {
         }
     }
 
-    override fun TensorStructure<Double>.div(value: Double): DoubleTensor {
-        val resBuffer = DoubleArray(tensor.numElements) { i ->
-            tensor.buffer.array()[tensor.bufferStart + i] / value
+    override fun Double.div(other: TensorStructure<Double>): DoubleTensor {
+        val resBuffer = DoubleArray(other.tensor.numElements) { i ->
+            other.tensor.buffer.array()[other.tensor.bufferStart + i] / this
         }
-        return DoubleTensor(tensor.shape, resBuffer)
+        return DoubleTensor(other.shape, resBuffer)
     }
 
+    override fun TensorStructure<Double>.div(value: Double): DoubleTensor = value / tensor
+
     override fun TensorStructure<Double>.div(other: TensorStructure<Double>): DoubleTensor {
         checkShapesCompatible(tensor, other)
         val resBuffer = DoubleArray(tensor.numElements) { i ->