feat: add RNN basic framework.

Author: SanftMonster

src/TensorFlowNET.Core/Extensions/DictionaryExtension.cs renamed to src/TensorFlowNET.Core/Common/Extensions/DictionaryExtension.cs

@@ -3,16 +3,16 @@
 using System.Collections.Generic;
 using System.Text;
 
-namespace Tensorflow.Extensions
+namespace Tensorflow.Common.Extensions
 {
     public static class JObjectExtensions
     {
         public static T? TryGetOrReturnNull<T>(this JObject obj, string key)
         {
             var res = obj[key];
-            if(res is null)
+            if (res is null)
             {
-                return default(T);
+                return default;
             }
             else
             {

src/TensorFlowNET.Core/Extensions/JObjectExtensions.cs renamed to src/TensorFlowNET.Core/Common/Extensions/JObjectExtensions.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Tensorflow.Common.Extensions
+{
+    public static class LinqExtensions
+    {
+#if NETSTANDARD2_0
+        public static IEnumerable<T> TakeLast<T>(this IEnumerable<T> sequence, int count)
+        {
+            return sequence.Skip(sequence.Count() - count);
+        }
+
+        public static IEnumerable<T> SkipLast<T>(this IEnumerable<T> sequence, int count)
+        {
+            return sequence.Take(sequence.Count() - count);
+        }
+#endif
+        public static Tensors ToTensors(this IEnumerable<Tensor> tensors)
+        {
+            return new Tensors(tensors);
+        }
+    }
+}

src/TensorFlowNET.Core/Common/Extensions/LinqExtensions.cs

@@ -0,0 +1,79 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Text;
+
+namespace Tensorflow.Common.Types
+{
+    public class GeneralizedTensorShape: IEnumerable<long?[]>
+    {
+        public TensorShapeConfig[] Shapes { get; set; }
+        /// <summary>
+        /// create a single-dim generalized Tensor shape.
+        /// </summary>
+        /// <param name="dim"></param>
+        public GeneralizedTensorShape(int dim)
+        {
+            Shapes = new TensorShapeConfig[] { new TensorShapeConfig() { Items = new long?[] { dim } } };
+        }
+
+        public GeneralizedTensorShape(Shape shape)
+        {
+            Shapes = new TensorShapeConfig[] { shape };
+        }
+
+        public GeneralizedTensorShape(TensorShapeConfig shape)
+        {
+            Shapes = new TensorShapeConfig[] { shape };
+        }
+
+        public GeneralizedTensorShape(TensorShapeConfig[] shapes)
+        {
+            Shapes = shapes;
+        }
+
+        public GeneralizedTensorShape(IEnumerable<Shape> shape)
+        {
+            Shapes = shape.Select(x => (TensorShapeConfig)x).ToArray();
+        }
+
+        public Shape ToSingleShape()
+        {
+            if (Shapes.Length != 1)
+            {
+                throw new ValueError("The generalized shape contains more than 1 dim.");
+            }
+            var shape_config = Shapes[0];
+            Debug.Assert(shape_config is not null);
+            return new Shape(shape_config.Items.Select(x => x is null ? -1 : x.Value).ToArray());
+        }
+
+        public long ToNumber()
+        {
+            if(Shapes.Length != 1 || Shapes[0].Items.Length != 1)
+            {
+                throw new ValueError("The generalized shape contains more than 1 dim.");
+            }
+            var res = Shapes[0].Items[0];
+            return res is null ? -1 : res.Value;
+        }
+
+        public Shape[] ToShapeArray()
+        {
+            return Shapes.Select(x => new Shape(x.Items.Select(y => y is null ? -1 : y.Value).ToArray())).ToArray();
+        }
+
+        public IEnumerator<long?[]> GetEnumerator()
+        {
+            foreach (var shape in Shapes)
+            {
+                yield return shape.Items;
+            }
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+    }
+}

src/TensorFlowNET.Core/Extensions/OneofExtension.cs renamed to src/TensorFlowNET.Core/Common/Extensions/OneofExtension.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tensorflow.Common.Types
+{
+    /// <summary>
+    /// This interface is used when some corresponding python methods have optional args.
+    /// For example, `Keras.Layer.Apply` generally takes three args as the inputs, while 
+    /// `Keras.Layer.RNN` takes more. Then when calling RNN, you should add `RnnOptionalArgs` 
+    /// as the parameter of the method.
+    /// </summary>
+    public interface IOptionalArgs
+    {
+        /// <summary>
+        /// The identifier of the class. It is not an argument but only something to 
+        /// separate different OptionalArgs.
+        /// </summary>
+        string Identifier { get; }
+    }
+}

src/TensorFlowNET.Core/Common/Types/GeneralizedTensorShape.cs

@@ -3,7 +3,7 @@
 using System.Collections.Generic;
 using System.Linq;
 
-namespace Tensorflow.Keras.Saving
+namespace Tensorflow.Common.Types
 {
     public class TensorShapeConfig
     {

src/TensorFlowNET.Core/Common/Types/IOptionalArgs.cs

@@ -1,17 +1,15 @@
 using Newtonsoft.Json;
 using System.Collections.Generic;
+using Tensorflow.Keras.Layers.Rnn;
 
 namespace Tensorflow.Keras.ArgsDefinition.Rnn
 {
+    // TODO(Rinne): add regularizers.
     public class RNNArgs : AutoSerializeLayerArgs
     {
-        public interface IRnnArgCell : ILayer
-        {
-            object state_size { get; }
-        }
         [JsonProperty("cell")]
         // TODO: the cell should be serialized with `serialize_keras_object`.
-        public IRnnArgCell Cell { get; set; } = null;
+        public IRnnCell Cell { get; set; } = null;
         [JsonProperty("return_sequences")]
         public bool ReturnSequences { get; set; } = false;
         [JsonProperty("return_state")]
@@ -34,6 +32,9 @@ public interface IRnnArgCell : ILayer
         public IInitializer KernelInitializer { get; set; }
         public IInitializer RecurrentInitializer { get; set; }
         public IInitializer BiasInitializer { get; set; }
+        public float Dropout { get; set; } = .0f;
+        public bool ZeroOutputForMask { get; set; } = false;
+        public float RecurrentDropout { get; set; } = .0f;
 
         // kernel_regularizer=None,
         // recurrent_regularizer=None,

src/TensorFlowNET.Core/Extensions/NamedTuple.cs renamed to src/TensorFlowNET.Core/Common/Types/NamedTuple.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Tensorflow.Common.Types;
+
+namespace Tensorflow.Keras.ArgsDefinition.Rnn
+{
+    public class RnnOptionalArgs: IOptionalArgs
+    {
+        public string Identifier => "Rnn";
+        public Tensor Mask { get; set; } = null;
+        public Tensors Constants { get; set; } = null;
+    }
+}