added method GetNextBatch to MnistDataSet

src/TensorFlowHub/MnistDataSet.cs

@@ -27,5 +27,54 @@ namespace Tensorflow.Hub
             labels.astype(dataType);
             Labels = labels;
         }
+
+        public (NDArray, NDArray) GetNextBatch(int batch_size, bool fake_data = false, bool shuffle = true)
+        {
+            var start = IndexInEpoch;
+            // Shuffle for the first epoch
+            if(EpochsCompleted == 0 && start == 0 && shuffle)
+            {
+                var perm0 = np.arange(NumOfExamples);
+                np.random.shuffle(perm0);
+                Data = Data[perm0];
+                Labels = Labels[perm0];
+            }
+
+            // Go to the next epoch
+            if (start + batch_size > NumOfExamples)
+            {
+                // Finished epoch
+                EpochsCompleted += 1;
+
+                // Get the rest examples in this epoch
+                var rest_num_examples = NumOfExamples - start;
+                //var images_rest_part = _images[np.arange(start, _num_examples)];
+                //var labels_rest_part = _labels[np.arange(start, _num_examples)];
+                // Shuffle the data
+                if (shuffle)
+                {
+                    var perm = np.arange(NumOfExamples);
+                    np.random.shuffle(perm);
+                    Data = Data[perm];
+                    Labels = Labels[perm];
+                }
+
+                start = 0;
+                IndexInEpoch = batch_size - rest_num_examples;
+                var end = IndexInEpoch;
+                var images_new_part = Data[np.arange(start, end)];
+                var labels_new_part = Labels[np.arange(start, end)];
+
+                /*return (np.concatenate(new float[][] { images_rest_part.Data<float>(), images_new_part.Data<float>() }, axis: 0),
+                    np.concatenate(new float[][] { labels_rest_part.Data<float>(), labels_new_part.Data<float>() }, axis: 0));*/
+                return (images_new_part, labels_new_part);
+            }
+            else
+            {
+                IndexInEpoch += batch_size;
+                var end = IndexInEpoch;
+                return (Data[np.arange(start, end)], Labels[np.arange(start, end)]);
+            }
+        }
     }
 }