tensor casting

kmath-noa/src/main/kotlin/space/kscience/kmath/noa/algebras.kt

@@ -11,6 +11,7 @@ import space.kscience.kmath.tensors.api.AnalyticTensorAlgebra
 import space.kscience.kmath.tensors.api.LinearOpsTensorAlgebra
 import space.kscience.kmath.tensors.api.Tensor
 import space.kscience.kmath.tensors.api.TensorAlgebra
+import space.kscience.kmath.tensors.core.TensorLinearStructure
 
 
 public sealed class NoaAlgebra<T, TensorType : NoaTensor<T>>
@@ -276,8 +277,17 @@ internal constructor(scope: NoaScope) : NoaAlgebra<T, TensorType>(scope), Linear
 public class NoaDoubleAlgebra(scope: NoaScope) :
     NoaPartialDivisionAlgebra<Double, NoaDoubleTensor>(scope) {
 
+    private fun Tensor<Double>.castHelper(): NoaDoubleTensor =
+        copyFromArray(
+            TensorLinearStructure(this.shape).indices().map(this::get).toMutableList().toDoubleArray(),
+            this.shape, Device.CPU
+        )
+
     override val Tensor<Double>.tensor: NoaDoubleTensor
-        get() = TODO("Not yet implemented")
+        get() = when (this) {
+            is NoaDoubleTensor -> this
+            else -> castHelper()
+        }
 
     override fun wrap(tensorHandle: TensorHandle): NoaDoubleTensor =
         NoaDoubleTensor(scope = scope, tensorHandle = tensorHandle)
@@ -342,8 +352,17 @@ public class NoaDoubleAlgebra(scope: NoaScope) :
 public class NoaFloatAlgebra(scope: NoaScope) :
     NoaPartialDivisionAlgebra<Float, NoaFloatTensor>(scope) {
 
+    private fun Tensor<Float>.castHelper(): NoaFloatTensor =
+        copyFromArray(
+            TensorLinearStructure(this.shape).indices().map(this::get).toMutableList().toFloatArray(),
+            this.shape, Device.CPU
+        )
+
     override val Tensor<Float>.tensor: NoaFloatTensor
-        get() = TODO("Not yet implemented")
+        get() = when (this) {
+            is NoaFloatTensor -> this
+            else -> castHelper()
+        }
 
     override fun wrap(tensorHandle: TensorHandle): NoaFloatTensor =
         NoaFloatTensor(scope = scope, tensorHandle = tensorHandle)
@@ -408,8 +427,17 @@ public class NoaFloatAlgebra(scope: NoaScope) :
 public class NoaLongAlgebra(scope: NoaScope) :
     NoaAlgebra<Long, NoaLongTensor>(scope) {
 
+    private fun Tensor<Long>.castHelper(): NoaLongTensor =
+        copyFromArray(
+            TensorLinearStructure(this.shape).indices().map(this::get).toMutableList().toLongArray(),
+            this.shape, Device.CPU
+        )
+
     override val Tensor<Long>.tensor: NoaLongTensor
-        get() = TODO("Not yet implemented")
+        get() = when (this) {
+            is NoaLongTensor -> this
+            else -> castHelper()
+        }
 
     override fun wrap(tensorHandle: TensorHandle): NoaLongTensor =
         NoaLongTensor(scope = scope, tensorHandle = tensorHandle)
@@ -459,8 +487,17 @@ public class NoaLongAlgebra(scope: NoaScope) :
 public class NoaIntAlgebra(scope: NoaScope) :
     NoaAlgebra<Int, NoaIntTensor>(scope) {
 
+    private fun Tensor<Int>.castHelper(): NoaIntTensor =
+        copyFromArray(
+            TensorLinearStructure(this.shape).indices().map(this::get).toMutableList().toIntArray(),
+            this.shape, Device.CPU
+        )
+
     override val Tensor<Int>.tensor: NoaIntTensor
-        get() = TODO("Not yet implemented")
+        get() = when (this) {
+            is NoaIntTensor -> this
+            else -> castHelper()
+        }
 
     override fun wrap(tensorHandle: TensorHandle): NoaIntTensor =
         NoaIntTensor(scope = scope, tensorHandle = tensorHandle)

kmath-noa/src/test/kotlin/space/kscience/kmath/noa/TestUtils.kt

@@ -7,6 +7,7 @@ package space.kscience.kmath.noa
 
 import space.kscience.kmath.misc.PerformancePitfall
 import space.kscience.kmath.noa.memory.NoaScope
+import space.kscience.kmath.tensors.core.TensorLinearStructure
 import kotlin.test.Test
 import kotlin.test.assertEquals