[GitHub] yzhliu commented on a change in pull request #12690: [MXNET-1000] get Ndarray real value and form it from a NDArray

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yzhliu commented on a change in pull request #12690: [MXNET-1000] get Ndarray real value and form it from a NDArray
URL: https://github.com/apache/incubator-mxnet/pull/12690#discussion_r250720021
 
 

 ##########
 File path: scala-package/core/src/main/scala/org/apache/mxnet/NDArray.scala
 ##########
 @@ -509,6 +510,63 @@ object NDArray extends NDArrayBase {
     array(sourceArr, shape, null)
   }
 
+  /**
+    * Create a new NDArray based on the structure of source Array
+    * @param sourceArr Array[Array...Array[MX_PRIMITIVE_TYPE]...]
+    * @param ctx context like to pass in
+    * @return an NDArray with the same shape of the input
+    */
+  def toNDArray(sourceArr: Array[_], ctx : Context = null) : NDArray = {
+    val shape = ArrayBuffer[Int]()
+    shapeGetter(sourceArr, shape, 0)
+    val container = new Array[Any](shape.product)
+    arrayCombiner(sourceArr, container, 0, container.length - 1)
+    val finalArr = container(0) match {
+      case f: Float => array(container.map(_.asInstanceOf[Float]), Shape(shape), ctx)
+      case d: Double => array(container.map(_.asInstanceOf[Double]), Shape(shape), ctx)
+      case _ => throw new IllegalArgumentException(s"Unsupported type ${container(0).getClass}")
+    }
+    finalArr
+  }
+
+  private def shapeGetter(sourceArr : Any,
+                          shape : ArrayBuffer[Int], shapeIdx : Int) : Unit = {
+    sourceArr match {
+      case arr: Array[_] if MX_PRIMITIVES.isValidType(arr(0)) => {
+        val arrLength = arr.length
+        if (shape.length == shapeIdx) {
+          shape += arrLength
+        }
+        require(shape(shapeIdx) == arrLength, "Each Array should have equal length")
+      }
+      case arr: Array[_] => {
+        val arrLength = arr.length
+        if (shape.length == shapeIdx) {
+          shape += arrLength
+        }
+        require(shape(shapeIdx) == arrLength,
+          s"Each Array should have equal length, expected ${shape(shapeIdx)}, get $arrLength")
+        arr.foreach(ele => shapeGetter(ele, shape, shapeIdx + 1))
+      }
+      case _ => throw new IllegalArgumentException(s"Wrong type passed: ${sourceArr.getClass}")
+    }
+  }
+
+  private def arrayCombiner(sourceArr : Any, arr : Array[Any],
 
 Review comment:
   better named flattenArray

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