Update tensor_util.cs

Author: novikov-alexander

src/TensorFlowNET.Core/Tensors/tensor_util.cs

@@ -1,4 +1,4 @@
-/*****************************************************************************
+/*****************************************************************************
    Copyright 2018 The TensorFlow.NET Authors. All Rights Reserved.
 
    Licensed under the Apache License, Version 2.0 (the "License");
@@ -135,6 +135,23 @@ T[] ExpandArrayToSize<T>(IList<T> src)
             TF_DataType.TF_QINT32
         };
 
+        private static TOut[,] ConvertArray2D<TIn, TOut>(TIn[,] inputArray, Func<TIn, TOut> converter)
+        {
+            var rows = inputArray.GetLength(0);
+            var cols = inputArray.GetLength(1);
+            var outputArray = new TOut[rows, cols];
+
+            for (var i = 0; i < rows; i++)
+            {
+                for (var j = 0; j < cols; j++)
+                {
+                    outputArray[i, j] = converter(inputArray[i, j]);
+                }
+            }
+
+            return outputArray;
+        }
+
         /// <summary>
         /// Create a TensorProto, invoked in graph mode
         /// </summary>
@@ -157,19 +174,16 @@ public static TensorProto make_tensor_proto(object values, TF_DataType dtype = T
             else if(origin_dtype != dtype)
             {
                 var new_system_dtype = dtype.as_system_dtype();
-                if (values is long[] long_values)
-                {
-                    if (dtype == TF_DataType.TF_INT32)
-                        values = long_values.Select(x => (int)Convert.ChangeType(x, new_system_dtype)).ToArray();
-                }
-                else if (values is double[] double_values)
+                
+                values = values switch
                 {
-                    if (dtype == TF_DataType.TF_FLOAT)
-                        values = double_values.Select(x => (float)Convert.ChangeType(x, new_system_dtype)).ToArray();
-                }
-                else
-                    values = Convert.ChangeType(values, new_system_dtype);
-
+                    long[] longValues when dtype == TF_DataType.TF_INT32 => longValues.Select(x => (int)x).ToArray(),
+                    float[] floatValues when dtype == TF_DataType.TF_DOUBLE => floatValues.Select(x => (double)x).ToArray(),
+                    float[,] float2DValues when dtype == TF_DataType.TF_DOUBLE => ConvertArray2D(float2DValues, Convert.ToDouble),
+                    double[] doubleValues when dtype == TF_DataType.TF_FLOAT => doubleValues.Select(x => (float)x).ToArray(),
+                    double[,] double2DValues when dtype == TF_DataType.TF_DOUBLE => ConvertArray2D(double2DValues, Convert.ToSingle),
+                    _ => Convert.ChangeType(values, new_system_dtype),
+                };
                 dtype = values.GetDataType();
             }