BasicLSTMCell

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

@@ -251,7 +251,7 @@ namespace Tensorflow
         ///    greater than <c>clip_value_max</c> are set to <c>clip_value_max</c>.
         /// </remarks>
         public Tensor clip_by_value (Tensor t, Tensor clip_value_min, Tensor clip_value_max, string name = "ClipByValue") 
-            => gen_ops.clip_by_value(t, clip_value_min, clip_value_max, name);
+            => clip_ops.clip_by_value(t, clip_value_min, clip_value_max, name);
 
         public Tensor sub(Tensor a, Tensor b) 
             => gen_math_ops.sub(a, b);

src/TensorFlowNET.Core/Framework/tensor_shape.cs

@@ -24,6 +24,16 @@ namespace Tensorflow.Framework
             }
         }
 
+        public static Dimension dimension_at_index(TensorShape shape, int index)
+        {
+            return shape.rank < 0 ?
+                new Dimension(-1) :
+                new Dimension(shape.dims[index]);
+        }
+
+        public static int dimension_value(Dimension dimension)
+            => dimension.value;
+
         public static TensorShape as_shape(this Shape shape)
              => new TensorShape(shape.Dimensions);
     }

src/TensorFlowNET.Core/Operations/NnOps/BasicLSTMCell.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using static Tensorflow.Binding;
+using Tensorflow.Operations.Activation;
+using Tensorflow.Keras.Engine;
+using Tensorflow.Operations;
+
+namespace Tensorflow
+{
+    /// <summary>
+    /// Basic LSTM recurrent network cell.
+    /// The implementation is based on: http://arxiv.org/abs/1409.2329.
+    /// </summary>
+    public class BasicLSTMCell : LayerRnnCell
+    {
+        int _num_units;
+        float _forget_bias;
+        bool _state_is_tuple;
+        IActivation _activation;
+
+        /// <summary>
+        /// Initialize the basic LSTM cell.
+        /// </summary>
+        /// <param name="num_units">The number of units in the LSTM cell.</param>
+        /// <param name="forget_bias"></param>
+        /// <param name="state_is_tuple"></param>
+        /// <param name="activation"></param>
+        /// <param name="reuse"></param>
+        /// <param name="name"></param>
+        /// <param name="dtype"></param>
+        public BasicLSTMCell(int num_units, float forget_bias = 1.0f, bool state_is_tuple = true,
+            IActivation activation = null, bool? reuse = null, string name = null,
+            TF_DataType dtype = TF_DataType.DtInvalid) : base(_reuse: reuse, name: name, dtype: dtype)
+        {
+            input_spec = new InputSpec(ndim: 2);
+            _num_units = num_units;
+            _forget_bias = forget_bias;
+            _state_is_tuple = state_is_tuple;
+            _activation = activation;
+            if (_activation == null)
+                _activation = tf.nn.tanh();
+        }
+
+        public LSTMStateTuple state_size
+        {
+            get
+            {
+                return _state_is_tuple ? 
+                    new LSTMStateTuple(_num_units, _num_units) : 
+                    (LSTMStateTuple)(2 * _num_units);
+            }
+        }
+    }
+}

src/TensorFlowNET.Core/Operations/BasicRNNCell.cs → src/TensorFlowNET.Core/Operations/NnOps/BasicRNNCell.cs

@@ -16,6 +16,7 @@
 
 using System;
 using Tensorflow.Keras.Engine;
+using Tensorflow.Operations;
 using static Tensorflow.Binding;
 
 namespace Tensorflow
@@ -25,7 +26,7 @@ namespace Tensorflow
         int _num_units;
         Func<Tensor, string, Tensor> _activation;
 
-        public override int state_size => _num_units;
+        public override LSTMStateTuple state_size => _num_units;
         public override int output_size => _num_units;
         public VariableV1 _kernel;
         string _WEIGHTS_VARIABLE_NAME = "kernel";

src/TensorFlowNET.Core/Operations/NnOps/LSTMStateTuple.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tensorflow.Operations
+{
+    /// <summary>
+    /// Tuple used by LSTM Cells for `state_size`, `zero_state`, and output state.
+    /// 
+    /// Stores two elements: `(c, h)`, in that order. Where `c` is the hidden state
+    /// and `h` is the output.
+    /// 
+    /// Only used when `state_is_tuple=True`.
+    /// </summary>
+    public class LSTMStateTuple
+    {
+        int c;
+        int h;
+
+        public LSTMStateTuple(int c)
+        {
+            this.c = c;
+        }
+
+        public LSTMStateTuple(int c, int h)
+        {
+            this.c = c;
+            this.h = h;
+        }
+
+        public static implicit operator int(LSTMStateTuple tuple)
+        {
+            return tuple.c;
+        }
+
+        public static implicit operator LSTMStateTuple(int c)
+        {
+            return new LSTMStateTuple(c);
+        }
+    }
+}

src/TensorFlowNET.Core/Operations/RNNCell.cs → src/TensorFlowNET.Core/Operations/NnOps/RNNCell.cs

@@ -49,7 +49,7 @@ namespace Tensorflow
         /// difference between TF and Keras RNN cell.
         /// </summary>
         protected bool _is_tf_rnn_cell = false;
-        public virtual int state_size { get; }
+        public virtual LSTMStateTuple state_size { get; }
 
         public virtual int output_size { get; }
 

src/TensorFlowNET.Core/Operations/NnOps/rnn.cs

@@ -18,13 +18,106 @@ using NumSharp;
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Tensorflow.Framework;
 using Tensorflow.Util;
 using static Tensorflow.Binding;
 
 namespace Tensorflow.Operations
 {
-    internal class rnn
+    public class rnn
     {
+        /// <summary>
+        /// Creates a bidirectional recurrent neural network.
+        /// </summary>
+        public static void static_bidirectional_rnn(BasicLSTMCell cell_fw, 
+            BasicLSTMCell cell_bw,
+            Tensor[] inputs,
+            Tensor initial_state_fw = null,
+            Tensor initial_state_bw = null,
+            TF_DataType dtype = TF_DataType.DtInvalid,
+            Tensor sequence_length = null,
+            string scope = null)
+        {
+            if (inputs == null || inputs.Length == 0)
+                throw new ValueError("inputs must not be empty");
+
+            tf_with(tf.variable_scope(scope ?? "bidirectional_rnn"), delegate
+            {
+                // Forward direction
+                tf_with(tf.variable_scope("fw"), fw_scope =>
+                {
+                    static_rnn(
+                      cell_fw,
+                      inputs,
+                      initial_state_fw,
+                      dtype,
+                      sequence_length,
+                      scope: fw_scope);
+                });
+            });
+        }
+
+        public static void static_rnn(BasicLSTMCell cell,
+            Tensor[] inputs,
+            Tensor initial_state,
+            TF_DataType dtype = TF_DataType.DtInvalid,
+            Tensor sequence_length = null,
+            VariableScope scope = null)
+        {
+            // Create a new scope in which the caching device is either
+            // determined by the parent scope, or is set to place the cached
+            // Variable using the same placement as for the rest of the RNN.
+            if (scope == null)
+                tf_with(tf.variable_scope("rnn"), varscope =>
+                {
+                    throw new NotImplementedException("static_rnn");
+                });
+            else
+                tf_with(tf.variable_scope(scope), varscope =>
+                {
+                    Dimension fixed_batch_size = null;
+                    Dimension batch_size = null;
+                    Tensor batch_size_tensor = null;
+
+                    // Obtain the first sequence of the input
+                    var first_input = inputs[0];
+                    if (first_input.TensorShape.rank != 1)
+                    {
+                        var input_shape = first_input.TensorShape.with_rank_at_least(2);
+                        fixed_batch_size = input_shape.dims[0];
+                        var flat_inputs = nest.flatten2(inputs);
+                        foreach (var flat_input in flat_inputs)
+                        {
+                            input_shape = flat_input.TensorShape.with_rank_at_least(2);
+                            batch_size = tensor_shape.dimension_at_index(input_shape, 0);
+                            var input_size = input_shape[1];
+                            fixed_batch_size.merge_with(batch_size);
+                            foreach (var (i, size) in enumerate(input_size.dims))
+                            {
+                                if (size < 0)
+                                    throw new ValueError($"Input size (dimension {i} of inputs) must be accessible via " +
+                                        "shape inference, but saw value None.");
+                            }
+                        }
+                    }
+                    else
+                        fixed_batch_size = first_input.TensorShape.with_rank_at_least(1).dims[0];
+
+                    if (tensor_shape.dimension_value(fixed_batch_size) >= 0)
+                        batch_size = tensor_shape.dimension_value(fixed_batch_size);
+                    else
+                        batch_size_tensor = array_ops.shape(first_input)[0];
+
+                    Tensor state = null;
+                    if (initial_state != null)
+                        state = initial_state;
+                    else
+                    {
+                        cell.get_initial_state(batch_size: batch_size_tensor, dtype: dtype);
+                    }
+                });
+        }
+
         public static (Tensor, Tensor) dynamic_rnn(RnnCell cell, Tensor inputs_tensor,
             Tensor sequence_length = null, Tensor initial_state = null, 
             TF_DataType dtype = TF_DataType.DtInvalid,

src/TensorFlowNET.Core/Operations/clip_ops.cs

@@ -0,0 +1,45 @@
+/*****************************************************************************
+   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.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using static Tensorflow.Binding;
+
+namespace Tensorflow
+{
+    public class clip_ops
+    {
+        public static Tensor clip_by_value(Tensor t, Tensor clip_value_min, Tensor clip_value_max, string name = null)
+        {
+            return tf_with(ops.name_scope(name, "clip_by_value", new { t, clip_value_min, clip_value_max }), delegate
+            {
+                var values = ops.convert_to_tensor(t, name: "t");
+                // Go through list of tensors, for each value in each tensor clip
+                var t_min = math_ops.minimum(values, clip_value_max);
+                // Assert that the shape is compatible with the initial shape,
+                // to prevent unintentional broadcasting.
+                _ = values.TensorShape.merge_with(t_min.shape);
+                var t_max = math_ops.maximum(t_min, clip_value_min, name: name);
+                _ = values.TensorShape.merge_with(t_max.shape);
+
+                return t_max;
+            });
+        }
+    }
+}

src/TensorFlowNET.Core/TensorFlow.Binding.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;netstandard2.0</TargetFrameworks>
+    <TargetFramework>netstandard2.0</TargetFramework>
     <AssemblyName>TensorFlow.NET</AssemblyName>
     <RootNamespace>Tensorflow</RootNamespace>
     <TargetTensorFlow>1.14.1</TargetTensorFlow>

src/TensorFlowNET.Core/Tensors/Dimension.cs

@@ -22,6 +22,12 @@ namespace Tensorflow
                 return new Dimension(_value);
         }
 
+        public static implicit operator Dimension(int value)
+            => new Dimension(value);
+
+        public static implicit operator int(Dimension dimension)
+            => dimension.value;
+
         public override string ToString() => $"Dimension({_value})";
     }
 }

src/TensorFlowNET.Core/Tensors/Tensor.cs

@@ -162,9 +162,9 @@ namespace Tensorflow
                 using (var status = new Status())
                 {
                     if (value == null)
-                        c_api.TF_GraphSetTensorShape(this.graph, this._as_tf_output(), null, -1, status);
+                        c_api.TF_GraphSetTensorShape(graph, _as_tf_output(), null, -1, status);
                     else
-                        c_api.TF_GraphSetTensorShape(this.graph, this._as_tf_output(), value.Select(Convert.ToInt64).ToArray(), value.Length, status);
+                        c_api.TF_GraphSetTensorShape(graph, _as_tf_output(), value.Select(Convert.ToInt64).ToArray(), value.Length, status);
 
                     status.Check(true);
                 }