kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/FloatBuffer.kt

@@ -43,6 +43,14 @@ public fun Buffer<Float>.toFloatArray(): FloatArray = when(this) {
     else -> FloatArray(size, ::get)
 }
 
+/**
+ * Returns a reference to [FloatArray] containing all of the elements of this [Buffer].
+ */
+public fun Buffer<Float>.unsafeToFloatArray(): FloatArray = when(this) {
+    is FloatBuffer -> array
+    else -> throw RuntimeException("Failed to cast Buffer to FloatArray")
+}
+
 /**
  * Returns [FloatBuffer] over this array.
  *

kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/IntBuffer.kt

@@ -42,6 +42,14 @@ public fun Buffer<Int>.toIntArray(): IntArray = when(this) {
     else -> IntArray(size, ::get)
 }
 
+/**
+ * Returns a reference to [IntArray] containing all of the elements of this [Buffer].
+ */
+public fun Buffer<Int>.unsafeToIntArray(): IntArray = when(this) {
+    is IntBuffer -> array
+    else -> throw RuntimeException("Failed to cast Buffer to IntArray")
+}
+
 /**
  * Returns [IntBuffer] over this array.
  *

kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/LongBuffer.kt

@@ -42,6 +42,14 @@ public fun Buffer<Long>.toLongArray(): LongArray = when(this) {
     else -> LongArray(size, ::get)
 }
 
+/**
+ * Returns a reference to [LongArray] containing all of the elements of this [Buffer].
+ */
+public fun Buffer<Long>.unsafeToLongArray(): LongArray = when(this) {
+    is LongBuffer -> array
+    else -> throw RuntimeException("Failed to cast Buffer to LongArray")
+}
+
 /**
  * Returns [LongBuffer] over this array.
  *

kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/RealBuffer.kt

@@ -47,6 +47,14 @@ public fun Buffer<Double>.toDoubleArray(): DoubleArray = when(this) {
     else -> DoubleArray(size, ::get)
 }
 
+/**
+ * Returns a reference to [DoubleArray] containing all of the elements of this [Buffer].
+ */
+public fun Buffer<Double>.unsafeToDoubleArray(): DoubleArray = when(this) {
+    is RealBuffer -> array
+    else -> throw RuntimeException("Failed to cast Buffer to DoubleArray")
+}
+
 /**
  * Returns [RealBuffer] over this array.
  *

kmath-core/src/commonMain/kotlin/space/kscience/kmath/tensors/RealLinearOpsTensorAlgebra.kt

@@ -1,7 +1,6 @@
 package space.kscience.kmath.tensors
 
-import space.kscience.kmath.structures.toDoubleArray
+import space.kscience.kmath.structures.unsafeToIntArray
-import space.kscience.kmath.structures.toIntArray
 
 public class RealLinearOpsTensorAlgebra :
     LinearOpsTensorAlgebra<Double, RealTensor>,
@@ -81,7 +80,7 @@ public class RealLinearOpsTensorAlgebra :
         // todo checks
         val n = lu.shape[0]
         val p = lu.zeroesLike()
-        pivots.buffer.toIntArray().forEachIndexed { i, pivot ->
+        pivots.buffer.unsafeToIntArray().forEachIndexed { i, pivot ->
             p[i, pivot] = 1.0
         }
         val l = lu.zeroesLike()

kmath-core/src/commonMain/kotlin/space/kscience/kmath/tensors/RealTensorAlgebra.kt

@@ -1,6 +1,6 @@
 package space.kscience.kmath.tensors
 
-import space.kscience.kmath.structures.toDoubleArray
+import space.kscience.kmath.structures.unsafeToDoubleArray
 
 
 public open class RealTensorAlgebra : TensorPartialDivisionAlgebra<Double, RealTensor> {
@@ -9,7 +9,7 @@ public open class RealTensorAlgebra : TensorPartialDivisionAlgebra<Double, RealT
         check(this.shape contentEquals intArrayOf(1)) {
             "Inconsistent value for tensor of shape ${shape.toList()}"
         }
-        return this.buffer.toDoubleArray()[0]
+        return this.buffer.unsafeToDoubleArray()[0]
     }
 
     override fun zeros(shape: IntArray): RealTensor {
@@ -32,13 +32,13 @@ public open class RealTensorAlgebra : TensorPartialDivisionAlgebra<Double, RealT
 
     override fun RealTensor.copy(): RealTensor {
         // should be rework as soon as copy() method for NDBuffer will be available
-        return RealTensor(this.shape, this.buffer.toDoubleArray().copyOf())
+        return RealTensor(this.shape, this.buffer.unsafeToDoubleArray().copyOf())
     }
 
 
     override fun Double.plus(other: RealTensor): RealTensor {
         val resBuffer = DoubleArray(other.buffer.size) { i ->
-            other.buffer.toDoubleArray()[i] + this
+            other.buffer.unsafeToDoubleArray()[i] + this
         }
         return RealTensor(other.shape, resBuffer)
     }
@@ -50,34 +50,34 @@ public open class RealTensorAlgebra : TensorPartialDivisionAlgebra<Double, RealT
         val newThis = broadcast[0]
         val newOther = broadcast[1]
         val resBuffer = DoubleArray(newThis.buffer.size) { i ->
-            newThis.buffer.toDoubleArray()[i] + newOther.buffer.toDoubleArray()[i]
+            newThis.buffer.unsafeToDoubleArray()[i] + newOther.buffer.unsafeToDoubleArray()[i]
         }
         return RealTensor(newThis.shape, resBuffer)
     }
 
     override fun RealTensor.plusAssign(value: Double) {
-        for (i in this.buffer.toDoubleArray().indices) {
+        for (i in this.buffer.unsafeToDoubleArray().indices) {
-            this.buffer.toDoubleArray()[i] += value
+            this.buffer.unsafeToDoubleArray()[i] += value
         }
     }
 
     override fun RealTensor.plusAssign(other: RealTensor) {
         //todo should be change with broadcasting
-        for (i in this.buffer.toDoubleArray().indices) {
+        for (i in this.buffer.unsafeToDoubleArray().indices) {
-            this.buffer.toDoubleArray()[i] += other.buffer.toDoubleArray()[i]
+            this.buffer.unsafeToDoubleArray()[i] += other.buffer.unsafeToDoubleArray()[i]
         }
     }
 
     override fun Double.minus(other: RealTensor): RealTensor {
         val resBuffer = DoubleArray(other.buffer.size) { i ->
-            this - other.buffer.toDoubleArray()[i]
+            this - other.buffer.unsafeToDoubleArray()[i]
         }
         return RealTensor(other.shape, resBuffer)
     }
 
     override fun RealTensor.minus(value: Double): RealTensor {
         val resBuffer = DoubleArray(this.buffer.size) { i ->
-            this.buffer.toDoubleArray()[i] - value
+            this.buffer.unsafeToDoubleArray()[i] - value
         }
         return RealTensor(this.shape, resBuffer)
     }
@@ -87,14 +87,14 @@ public open class RealTensorAlgebra : TensorPartialDivisionAlgebra<Double, RealT
         val newThis = broadcast[0]
         val newOther = broadcast[1]
         val resBuffer = DoubleArray(newThis.buffer.size) { i ->
-            newThis.buffer.toDoubleArray()[i] - newOther.buffer.toDoubleArray()[i]
+            newThis.buffer.unsafeToDoubleArray()[i] - newOther.buffer.unsafeToDoubleArray()[i]
         }
         return RealTensor(newThis.shape, resBuffer)
     }
 
     override fun RealTensor.minusAssign(value: Double) {
-        for (i in this.buffer.toDoubleArray().indices) {
+        for (i in this.buffer.unsafeToDoubleArray().indices) {
-            this.buffer.toDoubleArray()[i] -= value
+            this.buffer.unsafeToDoubleArray()[i] -= value
         }
     }
 
@@ -105,7 +105,7 @@ public open class RealTensorAlgebra : TensorPartialDivisionAlgebra<Double, RealT
     override fun Double.times(other: RealTensor): RealTensor {
         //todo should be change with broadcasting
         val resBuffer = DoubleArray(other.buffer.size) { i ->
-            other.buffer.toDoubleArray()[i] * this
+            other.buffer.unsafeToDoubleArray()[i] * this
         }
         return RealTensor(other.shape, resBuffer)
     }
@@ -116,28 +116,28 @@ public open class RealTensorAlgebra : TensorPartialDivisionAlgebra<Double, RealT
     override fun RealTensor.times(other: RealTensor): RealTensor {
         //todo should be change with broadcasting
         val resBuffer = DoubleArray(this.buffer.size) { i ->
-            this.buffer.toDoubleArray()[i] * other.buffer.toDoubleArray()[i]
+            this.buffer.unsafeToDoubleArray()[i] * other.buffer.unsafeToDoubleArray()[i]
         }
         return RealTensor(this.shape, resBuffer)
     }
 
     override fun RealTensor.timesAssign(value: Double) {
         //todo should be change with broadcasting
-        for (i in this.buffer.toDoubleArray().indices) {
+        for (i in this.buffer.unsafeToDoubleArray().indices) {
-            this.buffer.toDoubleArray()[i] *= value
+            this.buffer.unsafeToDoubleArray()[i] *= value
         }
     }
 
     override fun RealTensor.timesAssign(other: RealTensor) {
         //todo should be change with broadcasting
-        for (i in this.buffer.toDoubleArray().indices) {
+        for (i in this.buffer.unsafeToDoubleArray().indices) {
-            this.buffer.toDoubleArray()[i] *= other.buffer.toDoubleArray()[i]
+            this.buffer.unsafeToDoubleArray()[i] *= other.buffer.unsafeToDoubleArray()[i]
         }
     }
 
     override fun RealTensor.unaryMinus(): RealTensor {
         val resBuffer = DoubleArray(this.buffer.size) { i ->
-            this.buffer.toDoubleArray()[i].unaryMinus()
+            this.buffer.unsafeToDoubleArray()[i].unaryMinus()
         }
         return RealTensor(this.shape, resBuffer)
     }
@@ -158,14 +158,14 @@ public open class RealTensorAlgebra : TensorPartialDivisionAlgebra<Double, RealT
             newMultiIndex[i] = newMultiIndex[j].also { newMultiIndex[j] = newMultiIndex[i] }
 
             val linearIndex = resTensor.strides.offset(newMultiIndex)
-            resTensor.buffer.toDoubleArray()[linearIndex] = this.buffer.toDoubleArray()[offset]
+            resTensor.buffer.unsafeToDoubleArray()[linearIndex] = this.buffer.unsafeToDoubleArray()[offset]
         }
         return resTensor
     }
 
 
     override fun RealTensor.view(shape: IntArray): RealTensor {
-        return RealTensor(shape, this.buffer.toDoubleArray())
+        return RealTensor(shape, this.buffer.unsafeToDoubleArray())
     }
 
     override fun RealTensor.viewAs(other: RealTensor): RealTensor {

kmath-core/src/commonMain/kotlin/space/kscience/kmath/tensors/utils.kt

@@ -1,6 +1,6 @@
 package space.kscience.kmath.tensors
 
-import space.kscience.kmath.structures.toDoubleArray
+import space.kscience.kmath.structures.unsafeToDoubleArray
 import kotlin.math.max
 
 
@@ -55,7 +55,7 @@ internal inline fun broadcastTensors(vararg tensors: RealTensor): List<RealTenso
             }
 
             val curLinearIndex = tensor.strides.offset(curMultiIndex)
-            resTensor.buffer.toDoubleArray()[linearIndex] = tensor.buffer.toDoubleArray()[curLinearIndex]
+            resTensor.buffer.unsafeToDoubleArray()[linearIndex] = tensor.buffer.unsafeToDoubleArray()[curLinearIndex]
         }
         res.add(resTensor)
     }