Add VariableTest.Add test in UnitTest

src/TensorFlowNET.Core/Graphs/Graph.cs

@@ -288,7 +288,7 @@ namespace Tensorflow
             return _nodes_by_name.Values.Select(x => x).ToArray();
         }
 
-        public object get_collection(string name)
+        public object get_collection(string name, string scope = "")
         {
             return _collections.ContainsKey(name) ? _collections[name] : null;
         }

src/TensorFlowNET.Core/Operations/control_flow_ops.py.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tensorflow
+{
+    public class control_flow_ops
+    {
+        public static Operation group(Operation[] inputs)
+        {
+            return null;
+        }
+    }
+}

src/TensorFlowNET.Core/Python.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tensorflow
+{
+    /// <summary>
+    /// Mapping C# functions to Python
+    /// </summary>
+    public class Python
+    {
+        protected void print(object obj)
+        {
+            Console.WriteLine(obj.ToString());
+        }
+    }
+}

src/TensorFlowNET.Core/Variables/RefVariable.cs

@@ -12,7 +12,10 @@ namespace Tensorflow
         public bool _trainable;
         public Tensor _variable;
         public Tensor _snapshot;
-        public Operation op;
+
+        private Operation _initializer_op;
+        public Operation initializer => _initializer_op;
+        public Operation op => _initializer_op;
 
         public RefVariable(object initial_value,
             bool trainable = true,
@@ -81,7 +84,7 @@ namespace Tensorflow
                 // have an issue if these other variables aren't initialized first by
                 // using their initialized_value() method.
 
-                var _initializer_op = gen_state_ops.assign(_variable, _initial_value, validate_shape).op;
+                _initializer_op = gen_state_ops.assign(_variable, _initial_value, validate_shape).op;
 
                 if (!String.IsNullOrEmpty(caching_device))
                 {
@@ -92,7 +95,6 @@ namespace Tensorflow
                     _snapshot = gen_array_ops.identity(_variable, name = "read");
                 }
 
-                op = _initializer_op;
                 ops.add_to_collections(collections, this);
             }
         }

src/TensorFlowNET.Core/Variables/tf.variable.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tensorflow
+{
+    public static partial class tf
+    {
+        public static Operation global_variables_initializer()
+        {
+            var g = variables.global_variables();
+            return variables.variables_initializer(g as RefVariable[]);
+        }
+    }
+}

src/TensorFlowNET.Core/Variables/variables.py.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text;
 
 namespace Tensorflow
@@ -14,5 +15,32 @@ namespace Tensorflow
         {
             return ops.get_collection(ops.GraphKeys.TRAINABLE_VARIABLES);
         }
+
+        /// <summary>
+        /// Returns global variables.
+        /// </summary>
+        /// <param name="scope">
+        /// (Optional.) A string. If supplied, the resulting list is filtered
+        /// to include only items whose `name` attribute matches `scope` using
+        /// `re.match`. Items without a `name` attribute are never returned if a
+        /// scope is supplied. The choice of `re.match` means that a `scope` without
+        /// special tokens filters by prefix.
+        /// </param>
+        /// <returns>A list of `Variable` objects.</returns>
+        public static object global_variables(string scope = "")
+        {
+            return ops.get_collection(ops.GraphKeys.GLOBAL_VARIABLES, scope);
+        }
+
+        /// <summary>
+        /// Returns an Op that initializes a list of variables.
+        /// </summary>
+        /// <param name="var_list">List of `Variable` objects to initialize.</param>
+        /// <param name="name">Optional name for the returned operation.</param>
+        /// <returns>An Op that run the initializers of all the specified variables.</returns>
+        public static Operation variables_initializer(RefVariable[] var_list, string name = "init")
+        {
+            return control_flow_ops.group(var_list.Select(x => x.initializer).ToArray());
+        }
     }
 }

src/TensorFlowNET.Core/ops.py.cs

@@ -24,9 +24,23 @@ namespace Tensorflow
             graph.add_to_collections(names, value);
         }
 
-        public static object get_collection(string key)
+        /// <summary>
+        /// Wrapper for `Graph.get_collection()` using the default graph.
+        /// contains many standard names for collections.
+        /// </summary>
+        /// <param name="key">
+        /// The key for the collection. For example, the `GraphKeys` class
+        /// </param>
+        /// <param name="scope"></param>
+        /// <returns>
+        /// The list of values in the collection with the given `name`, or
+        /// an empty list if no value has been added to that collection. The
+        /// list contains the values in the order under which they were
+        /// collected.
+        /// </returns>
+        public static object get_collection(string key, string scope = "")
         {
-            return get_default_graph().get_collection(key);
+            return get_default_graph().get_collection(key, scope);
         }
 
         public static Graph get_default_graph()

test/TensorFlowNET.UnitTest/VariableTest.cs

@@ -7,7 +7,7 @@ using Tensorflow;
 namespace TensorFlowNET.UnitTest
 {
     [TestClass]
-    public class VariableTest
+    public class VariableTest : Python
     {
         [TestMethod]
         public void StringVar()
@@ -22,5 +22,28 @@ namespace TensorFlowNET.UnitTest
             var x = tf.Variable(3);
             var y = tf.Variable(6f);
         }
+
+        /// <summary>
+        /// https://databricks.com/tensorflow/variables
+        /// </summary>
+        [TestMethod]
+        public void Add()
+        {
+            var x = tf.Variable(0, name: "x");
+
+            var model = tf.global_variables_initializer();
+
+            using (var session = tf.Session())
+            {
+                /*session.run(model);
+                for(int i = 0; i < 5; i++)
+                {
+                    x = x + 1;
+                    var result = session.run(x);
+                    print(result);
+                }*/
+            }
+
+        }
     }
 }