Add support for variables, based on the guidance from Asim Shankar, and https://github.com/asimshankar/tensorflow/tree/govars/tensorflow/go/v

migueldeicaza · migueldeicaza · commit a796177ac955 · 2017-02-11T22:26:26.000-05:00
diff --git a/SampleTest/SampleTest.cs b/SampleTest/SampleTest.cs
@@ -386,6 +386,40 @@ void BasicVariables ()
 			}
 		}
 
+		//
+		// Shows the use of Variable
+		//
+		void TestVariable ()
+		{
+			Console.WriteLine ("Variables");
+			var status = new TFStatus ();
+			using (var g = new TFGraph ()) {
+				var initValue = g.Const (1.5);
+				var increment = g.Const (0.5);
+				TFOperation init;
+				TFOutput value;
+				var handle = g.Variable (initValue, out init, out value);
+
+				// Add 0.5 and assign to the variable.
+				// Perhaps using op.AssignAddVariable would be better,
+				// but demonstrating with Add and Assign for now.
+				var update = g.AssignVariableOp (handle, g.Add (value, increment));
+
+				var s = new TFSession (g);
+				// Must first initialize all the variables.
+				s.GetRunner ().AddTarget (init).Run (status);
+				Assert (status);
+				// Now print the value, run the update op and repeat
+				// Ignore errors.
+				for (int i = 0; i < 5; i++) {
+					// Read and update
+					var result = s.GetRunner ().Fetch (value).AddTarget (update).Run ();
+
+					Console.WriteLine ("Result of variable read {0} -> {1}", i, result [0].GetValue ());
+				}
+			}
+		}
+
 		void BasicMatrix ()
 		{
 			Console.WriteLine ("Basic matrix");
@@ -466,6 +500,7 @@ public static void Main (string [] args)
 			t.TestImportGraphDef ();
 			t.TestSession ();
 			t.TestOperationOutputListSize ();
+			t.TestVariable ();
 
 			// Current failing test
 			t.TestOutputShape ();
diff --git a/TensorFlowSharp/OperationsExtras.cs b/TensorFlowSharp/OperationsExtras.cs
@@ -60,5 +60,30 @@ public TFOutput ReduceSum (TFOutput input, TFOutput? axis = null, bool? keep_dim
 		{
 			return Sum (input, this.ReduceDims (input, axis), keep_dims, operName);
 		}
+
+		/// <summary>
+		/// Variable node, with a starting initial value.
+		/// </summary>
+		/// <param name="initialValue">Initial value.</param>
+		/// <param name="init">Returns the operation that initializes the value of the variable.</param>
+		/// <param name="value">Returns the value of the variable.</param>
+		/// <param name="operName">Operation name, optional.</param>
+		/// <returns>The returning TFOutput returns the handle to the variable.</returns>
+		public TFOutput Variable (TFOutput initialValue, out TFOperation init, out TFOutput value, string operName = null)
+		{
+			var scopeName = MakeName ("Variable", operName);
+
+			using (var newScope = WithScope (scopeName)) {
+				var type = initialValue.OutputType;
+				var handle = VarHandleOp (type, new TFShape (GetShape (initialValue)));
+				using (var aScope = WithScope ("Assign")) {
+					init = AssignVariableOp (handle, initialValue);
+					using (var rScope = WithScope ("Read")) {
+						value = ReadVariableOp (handle, type);
+						return handle;
+					}
+				}
+			}
+		}
 	}
 }
