Add BasicRNNCell, LayerRNNCell, RNNCell,

Change nest.flatten to generic.

docs/source/ConvolutionNeuralNetwork.md

@@ -346,4 +346,5 @@ Get started with the implementation:
    }
    ```
 
-![cnn-reuslt](../assets/cnn-result.png)
+![](../assets/cnn-result.png)
+

src/TensorFlowNET.Core/APIs/tf.nn.cs

@@ -16,9 +16,11 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text;
 using Tensorflow.Operations;
 using Tensorflow.Operations.Activation;
+using Tensorflow.Util;
 using static Tensorflow.Python;
 
 namespace Tensorflow
@@ -68,6 +70,33 @@ namespace Tensorflow
                 return nn_ops.dropout_v2(x, rate: rate_tensor, noise_shape: noise_shape, seed: seed, name: name);
             }
 
+            /// <summary>
+            /// Creates a recurrent neural network specified by RNNCell `cell`.
+            /// </summary>
+            /// <param name="cell">An instance of RNNCell.</param>
+            /// <param name="inputs">The RNN inputs.</param>
+            /// <param name="dtype"></param>
+            /// <param name="swap_memory"></param>
+            /// <param name="time_major"></param>
+            /// <returns>A pair (outputs, state)</returns>
+            public static (Tensor, Tensor) dynamic_rnn(RNNCell cell, Tensor inputs, TF_DataType dtype = TF_DataType.DtInvalid,
+                bool swap_memory = false, bool time_major = false)
+            {
+                with(variable_scope("rnn"), scope =>
+                {
+                    VariableScope varscope = scope;
+                    var flat_input = nest.flatten(inputs);
+
+                    if (!time_major)
+                    {
+                        flat_input = flat_input.Select(x => ops.convert_to_tensor(x)).ToList();
+                        //flat_input = flat_input.Select(x => _transpose_batch_time(x)).ToList();
+                    }
+                });
+
+                throw new NotImplementedException("");
+            }
+
             public static (Tensor, Tensor) moments(Tensor x,
                 int[] axes,
                 string name = null,

src/TensorFlowNET.Core/Operations/BasicRNNCell.cs

@@ -1,10 +1,48 @@
-using System;
+/*****************************************************************************
+   Copyright 2018 The TensorFlow.NET Authors. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+******************************************************************************/
+
+using System;
 using System.Collections.Generic;
 using System.Text;
+using Tensorflow.Keras.Engine;
+using Tensorflow.Operations.Activation;
 
 namespace Tensorflow
 {
-    public class BasicRNNCell
+    public class BasicRNNCell : LayerRNNCell
     {
+        int _num_units;
+        Func<Tensor, string, Tensor> _activation;
+
+        public BasicRNNCell(int num_units,
+            Func<Tensor, string, Tensor> activation = null,
+            bool? reuse = null,
+            string name = null,
+            TF_DataType dtype = TF_DataType.DtInvalid) : base(_reuse: reuse, 
+                name: name, 
+                dtype: dtype)
+        {
+            // Inputs must be 2-dimensional.
+            input_spec = new InputSpec(ndim: 2);
+
+            _num_units = num_units;
+            if (activation == null)
+                _activation = math_ops.tanh;
+            else
+                _activation = activation;
+        }
     }
 }

src/TensorFlowNET.Core/Operations/LayerRNNCell.cs

@@ -0,0 +1,33 @@
+/*****************************************************************************
+   Copyright 2018 The TensorFlow.NET Authors. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+******************************************************************************/
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tensorflow
+{
+    public class LayerRNNCell : RNNCell
+    {
+        public LayerRNNCell(bool? _reuse = null,
+            string name = null,
+            TF_DataType dtype = TF_DataType.DtInvalid) : base(_reuse: _reuse,
+                    name: name,
+                    dtype: dtype)
+        {
+        }
+    }
+}

src/TensorFlowNET.Core/Operations/RNNCell.cs

@@ -0,0 +1,63 @@
+/*****************************************************************************
+   Copyright 2018 The TensorFlow.NET Authors. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+******************************************************************************/
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tensorflow
+{
+    /// <summary>
+    /// Abstract object representing an RNN cell.
+    /// 
+    /// Every `RNNCell` must have the properties below and implement `call` with
+    /// the signature `(output, next_state) = call(input, state)`.  The optional
+    /// third input argument, `scope`, is allowed for backwards compatibility
+    /// purposes; but should be left off for new subclasses.
+    /// 
+    /// This definition of cell differs from the definition used in the literature.
+    /// In the literature, 'cell' refers to an object with a single scalar output.
+    /// This definition refers to a horizontal array of such units.
+    /// 
+    /// An RNN cell, in the most abstract setting, is anything that has
+    /// a state and performs some operation that takes a matrix of inputs.
+    /// This operation results in an output matrix with `self.output_size` columns.
+    /// If `self.state_size` is an integer, this operation also results in a new
+    /// state matrix with `self.state_size` columns.  If `self.state_size` is a
+    /// (possibly nested tuple of) TensorShape object(s), then it should return a
+    /// matching structure of Tensors having shape `[batch_size].concatenate(s)`
+    /// for each `s` in `self.batch_size`.
+    /// </summary>
+    public abstract class RNNCell : Layers.Layer
+    {
+        /// <summary>
+        /// Attribute that indicates whether the cell is a TF RNN cell, due the slight
+        /// difference between TF and Keras RNN cell.
+        /// </summary>
+        protected bool _is_tf_rnn_cell = false;
+
+        public RNNCell(bool trainable = true,
+            string name = null,
+            TF_DataType dtype = TF_DataType.DtInvalid,
+            bool? _reuse = null) : base(trainable: trainable, 
+                    name: name, 
+                    dtype: dtype,
+                    _reuse: _reuse)
+        {
+            _is_tf_rnn_cell = true;
+        }
+    }
+}

src/TensorFlowNET.Core/Operations/math_ops.cs

@@ -551,6 +551,9 @@ namespace Tensorflow
             });
         }
 
+        public static Tensor tanh(Tensor x, string name = null)
+            => gen_math_ops.tanh(x, name);
+
         public static Tensor truediv(Tensor x, Tensor y, string name = null)
             => _truediv_python3(x, y, name);
 

src/TensorFlowNET.Core/Operations/rnn_cell_impl.cs

@@ -7,8 +7,6 @@ namespace Tensorflow.Operations
     public class rnn_cell_impl
     {
         public BasicRNNCell BasicRNNCell(int num_units)
-        {
-            throw new NotImplementedException();
-        }
+            => new BasicRNNCell(num_units);
     }
 }

src/TensorFlowNET.Core/Util/nest.py.cs

@@ -214,14 +214,14 @@ namespace Tensorflow.Util
         //# See the swig file (util.i) for documentation.
         //flatten = _pywrap_tensorflow.Flatten
 
-        public static List<object> flatten(object structure)
+        public static List<T> flatten<T>(T structure)
         {
-            var list = new List<object>();
+            var list = new List<T>();
             _flatten_recursive(structure, list);
             return list;
         }
 
-        private static void _flatten_recursive(object obj, List<object> list)
+        private static void _flatten_recursive<T>(T obj, List<T> list)
         {
             if (obj is string)
             {
@@ -232,7 +232,7 @@ namespace Tensorflow.Util
             {
                 var dict = obj as IDictionary;
                 foreach (var key in _sorted(dict))
-                    _flatten_recursive(dict[key], list);
+                    _flatten_recursive((T)dict[key], list);
                 return;
             }
             if (obj is NDArray)
@@ -244,7 +244,7 @@ namespace Tensorflow.Util
             {
                 var structure = obj as IEnumerable;
                 foreach (var child in structure)
-                    _flatten_recursive(child, list);
+                    _flatten_recursive((T)child, list);
                 return;
             }
             list.Add(obj);

test/TensorFlowNET.Examples/ImageProcessing/DigitRecognitionRNN.cs

@@ -25,14 +25,12 @@ using static Tensorflow.Python;
 namespace TensorFlowNET.Examples.ImageProcess
 {
     /// <summary>
-    /// Convolutional Neural Network classifier for Hand Written Digits
-    /// CNN architecture with two convolutional layers, followed by two fully-connected layers at the end.
-    /// Use Stochastic Gradient Descent (SGD) optimizer. 
-    /// http://www.easy-tensorflow.com/tf-tutorials/convolutional-neural-nets-cnns/cnn1
+    /// Recurrent Neural Network for handwritten digits MNIST.
+    /// https://medium.com/machine-learning-algorithms/mnist-using-recurrent-neural-network-2d070a5915a2
     /// </summary>
     public class DigitRecognitionRNN : IExample
     {
-        public bool Enabled { get; set; } = false;
+        public bool Enabled { get; set; } = true;
         public bool IsImportingGraph { get; set; } = false;
 
         public string Name => "MNIST RNN";
@@ -84,6 +82,7 @@ namespace TensorFlowNET.Examples.ImageProcess
             var X = tf.placeholder(tf.float32, new[] { -1, n_steps, n_inputs });
             var y = tf.placeholder(tf.int32, new[] { -1 });
             var cell = tf.nn.rnn_cell.BasicRNNCell(num_units: n_neurons);
+            var (output, state) = tf.nn.dynamic_rnn(cell, X, dtype: tf.float32);
 
             return graph;
         }
@@ -154,6 +153,7 @@ namespace TensorFlowNET.Examples.ImageProcess
             print("Size of:");
             print($"- Training-set:\t\t{len(mnist.train.data)}");
             print($"- Validation-set:\t{len(mnist.validation.data)}");
+            print($"- Test-set:\t\t{len(mnist.test.data)}");
         }
 
         public Graph ImportGraph() => throw new NotImplementedException();

test/TensorFlowNET.UnitTest/nest_test/NestTest.cs

@@ -78,8 +78,8 @@ namespace TensorFlowNET.UnitTest.nest_test
             self.assertEqual((((restructured_from_flat[1] as object[])[0] as object[])[0] as Hashtable)["y"], 0);
 
             self.assertEqual(new List<object> { 5 }, nest.flatten(5));
-            flat = nest.flatten(np.array(new[] { 5 }));
-            self.assertEqual(new object[] { np.array(new int[] { 5 }) }, flat);
+            var flat1 = nest.flatten(np.array(new[] { 5 }));
+            self.assertEqual(new object[] { np.array(new int[] { 5 }) }, flat1);
 
             self.assertEqual("a", nest.pack_sequence_as(5, new List<object> { "a" }));
             self.assertEqual(np.array(new[] { 5 }),