More informative toString for NDBuffer and Complex

examples/src/main/kotlin/kscience/kmath/operations/ComplexDemo.kt

@@ -5,15 +5,19 @@ import kscience.kmath.structures.NDField
 import kscience.kmath.structures.complex
 
 fun main() {
+    // 2d element
     val element = NDElement.complex(2, 2) { index: IntArray ->
         Complex(index[0].toDouble() - index[1].toDouble(), index[0].toDouble() + index[1].toDouble())
     }
+    println(element)
 
-    val compute = (NDField.complex(8)) {
+    // 1d element operation
+    val result = with(NDField.complex(8)) {
         val a = produce { (it) -> i * it - it.toDouble() }
         val b = 3
         val c = Complex(1.0, 1.0)
 
         (a pow b) + c
     }
+    println(result)
 }

kmath-core/src/commonMain/kotlin/kscience/kmath/operations/Complex.kt

@@ -176,6 +176,11 @@ public data class Complex(val re: Double, val im: Double) : FieldElement<Complex
 
     override fun compareTo(other: Complex): Int = r.compareTo(other.r)
 
+    override fun toString(): String {
+        return "($re + i*$im)"
+    }
+
+
     public companion object : MemorySpec<Complex> {
         override val objectSize: Int = 16
 

kmath-core/src/commonMain/kotlin/kscience/kmath/structures/NDStructure.kt

@@ -70,7 +70,7 @@ public interface NDStructure<T> {
         public fun <T> build(
             strides: Strides,
             bufferFactory: BufferFactory<T> = Buffer.Companion::boxing,
-            initializer: (IntArray) -> T
+            initializer: (IntArray) -> T,
         ): BufferNDStructure<T> =
             BufferNDStructure(strides, bufferFactory(strides.linearSize) { i -> initializer(strides.index(i)) })
 
@@ -79,40 +79,40 @@ public interface NDStructure<T> {
          */
         public inline fun <reified T : Any> auto(
             strides: Strides,
-            crossinline initializer: (IntArray) -> T
+            crossinline initializer: (IntArray) -> T,
         ): BufferNDStructure<T> =
             BufferNDStructure(strides, Buffer.auto(strides.linearSize) { i -> initializer(strides.index(i)) })
 
         public inline fun <T : Any> auto(
             type: KClass<T>,
             strides: Strides,
-            crossinline initializer: (IntArray) -> T
+            crossinline initializer: (IntArray) -> T,
         ): BufferNDStructure<T> =
             BufferNDStructure(strides, Buffer.auto(type, strides.linearSize) { i -> initializer(strides.index(i)) })
 
         public fun <T> build(
             shape: IntArray,
             bufferFactory: BufferFactory<T> = Buffer.Companion::boxing,
-            initializer: (IntArray) -> T
+            initializer: (IntArray) -> T,
         ): BufferNDStructure<T> = build(DefaultStrides(shape), bufferFactory, initializer)
 
         public inline fun <reified T : Any> auto(
             shape: IntArray,
-            crossinline initializer: (IntArray) -> T
+            crossinline initializer: (IntArray) -> T,
         ): BufferNDStructure<T> =
             auto(DefaultStrides(shape), initializer)
 
         @JvmName("autoVarArg")
         public inline fun <reified T : Any> auto(
             vararg shape: Int,
-            crossinline initializer: (IntArray) -> T
+            crossinline initializer: (IntArray) -> T,
         ): BufferNDStructure<T> =
             auto(DefaultStrides(shape), initializer)
 
         public inline fun <T : Any> auto(
             type: KClass<T>,
             vararg shape: Int,
-            crossinline initializer: (IntArray) -> T
+            crossinline initializer: (IntArray) -> T,
         ): BufferNDStructure<T> =
             auto(type, DefaultStrides(shape), initializer)
     }
@@ -274,6 +274,22 @@ public abstract class NDBuffer<T> : NDStructure<T> {
         result = 31 * result + buffer.hashCode()
         return result
     }
+
+    override fun toString(): String {
+        val bufferRepr: String = when (shape.size) {
+            1 -> buffer.asSequence().joinToString(prefix = "[", postfix = "]", separator = ", ")
+            2 -> (0 until shape[0]).joinToString(prefix = "[", postfix = "]", separator = ", ") { i ->
+                (0 until shape[1]).joinToString(prefix = "[", postfix = "]", separator = ", ") { j ->
+                    val offset = strides.offset(intArrayOf(i, j))
+                    buffer[offset].toString()
+                }
+            }
+            else -> "..."
+        }
+        return "NDBuffer(shape=${shape.contentToString()}, buffer=$bufferRepr)"
+    }
+
+
 }
 
 /**
@@ -281,7 +297,7 @@ public abstract class NDBuffer<T> : NDStructure<T> {
  */
 public class BufferNDStructure<T>(
     override val strides: Strides,
-    override val buffer: Buffer<T>
+    override val buffer: Buffer<T>,
 ) : NDBuffer<T>() {
     init {
         if (strides.linearSize != buffer.size) {
@@ -295,7 +311,7 @@ public class BufferNDStructure<T>(
  */
 public inline fun <T, reified R : Any> NDStructure<T>.mapToBuffer(
     factory: BufferFactory<R> = Buffer.Companion::auto,
-    crossinline transform: (T) -> R
+    crossinline transform: (T) -> R,
 ): BufferNDStructure<R> {
     return if (this is BufferNDStructure<T>)
         BufferNDStructure(this.strides, factory.invoke(strides.linearSize) { transform(buffer[it]) })
@@ -310,7 +326,7 @@ public inline fun <T, reified R : Any> NDStructure<T>.mapToBuffer(
  */
 public class MutableBufferNDStructure<T>(
     override val strides: Strides,
-    override val buffer: MutableBuffer<T>
+    override val buffer: MutableBuffer<T>,
 ) : NDBuffer<T>(), MutableNDStructure<T> {
 
     init {
@@ -324,7 +340,7 @@ public class MutableBufferNDStructure<T>(
 
 public inline fun <reified T : Any> NDStructure<T>.combine(
     struct: NDStructure<T>,
-    crossinline block: (T, T) -> T
+    crossinline block: (T, T) -> T,
 ): NDStructure<T> {
     require(shape.contentEquals(struct.shape)) { "Shape mismatch in structure combination" }
     return NDStructure.auto(shape) { block(this[it], struct[it]) }