Support autograph.to_graph under graph mode.

src/TensorFlowNET.Core/Graphs/AutoGraph.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics;
 using System.Linq;
 using static Tensorflow.Binding;
 
@@ -6,14 +7,14 @@ namespace Tensorflow.Graphs
 {
     public class AutoGraph
     {
-        public Func<Tensor, Tensor> to_graph(Func<Tensor, Tensor> func)
+        public Func<Tensor, Tensor> to_graph(Func<Tensor, Tensor> func, TF_DataType dtype = TF_DataType.TF_INT32)
         {
             string func_name = $"{func.Method.Name}_{ops.uid_function()}";
 
             var graph = new FuncGraph(func_name);
             graph.as_default();
 
-            var input = tf.placeholder(tf.int32);
+            var input = tf.placeholder(dtype);
             var output = func(input);
 
             var opers = graph._nodes_by_name.Values.Select(x => x as Operation).ToArray();
@@ -26,25 +27,33 @@ namespace Tensorflow.Graphs
 
             return (Tensor input) =>
             {
-                var result = tf.Runner.TFE_Execute(tf.Context,
-                    tf.Context.DeviceName,
-                    func_name,
-                    new[] { input },
-                    null,
-                    1);
-                return result[0];
+                if (tf.executing_eagerly())
+                {
+                    var result = tf.Runner.TFE_Execute(tf.Context,
+                        tf.Context.DeviceName,
+                        func_name,
+                        new[] { input },
+                        null,
+                        1);
+                    return result[0];
+                }
+                using (var s = tf.Session(input.graph))
+                {
+                    var output = func(input);
+                    return output;
+                }
             };
         }
 
-        public Func<Tensor, Tensor, Tensor> to_graph(Func<Tensor, Tensor, Tensor> func)
+        public Func<Tensor, Tensor, Tensor> to_graph(Func<Tensor, Tensor, Tensor> func, params TF_DataType[] dtypes)
         {
             string func_name = $"{func.Method.Name}_{ops.uid_function()}";
 
             var graph = new FuncGraph(func_name);
             graph.as_default();
 
-            var input1 = tf.placeholder(tf.int32);
-            var input2 = tf.placeholder(tf.int32);
+            var input1 = tf.placeholder(dtypes.Length >= 1 ? dtypes[0] : tf.int32);
+            var input2 = tf.placeholder(dtypes.Length >= 2 ? dtypes[1] : tf.int32);
             var output = func(input1, input2);
 
             var opers = graph._nodes_by_name.Values.Select(x => x as Operation).ToArray();
@@ -56,13 +65,22 @@ namespace Tensorflow.Graphs
             
             return (Tensor a, Tensor b) =>
             {
-                var result = tf.Runner.TFE_Execute(tf.Context,
+                if (tf.executing_eagerly())
+                {
+                    var result = tf.Runner.TFE_Execute(tf.Context,
                     tf.Context.DeviceName,
                     func_name,
                     new[] { a, b },
                     null,
                     1);
-                return result[0];
+                    return result[0];
+                }
+                using (var s = tf.Session(a.graph))
+                {
+                    Debug.Assert(a.graph == b.graph);
+                    var output = func(a, b);
+                    return output;
+                }
             };
         }
     }