diff --git a/src/TensorFlowNET.Core/Device/c_api.device.cs b/src/TensorFlowNET.Core/Device/c_api.device.cs
new file mode 100644
index 00000000..2ce79a3e
--- /dev/null
+++ b/src/TensorFlowNET.Core/Device/c_api.device.cs
@@ -0,0 +1,32 @@
+/*****************************************************************************
+   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.Runtime.InteropServices;
+
+namespace Tensorflow
+{
+    public partial class c_api
+    {
+        /// <summary>
+        /// Specify the device for `desc`.  Defaults to empty, meaning unconstrained.
+        /// </summary>
+        /// <param name="desc"></param>
+        /// <param name="device"></param>
+        [DllImport(TensorFlowLibName)]
+        public static extern void TF_SetDevice(IntPtr desc, string device);
+    }
+}
diff --git a/src/TensorFlowNET.Core/Graphs/_ControlDependenciesController.cs b/src/TensorFlowNET.Core/Graphs/_ControlDependenciesController.cs
index 55e321df..63285bae 100644
--- a/src/TensorFlowNET.Core/Graphs/_ControlDependenciesController.cs
+++ b/src/TensorFlowNET.Core/Graphs/_ControlDependenciesController.cs
@@ -69,7 +69,9 @@ namespace Tensorflow
                 _new_stack = false;
             }
 
-            _seen_nodes = new List<ITensorOrOperation>();
+            _seen_nodes = new List<ITensorOrOperation>();
+            _old_stack = null;
+            _old_control_flow_context = null;
         }
 
         public void add_op(ITensorOrOperation op)
diff --git a/src/TensorFlowNET.Core/Keras/Layers/BatchNormalization.cs b/src/TensorFlowNET.Core/Keras/Layers/BatchNormalization.cs
index 57311e8b..9b42eaaa 100644
--- a/src/TensorFlowNET.Core/Keras/Layers/BatchNormalization.cs
+++ b/src/TensorFlowNET.Core/Keras/Layers/BatchNormalization.cs
@@ -139,7 +139,7 @@ namespace Tensorflow.Keras.Layers
             built = true;
         }
 
-        protected override (Tensor, Tensor) call(Tensor inputs, Tensor training = null)
+        protected override (Tensor, Tensor) call(Tensor inputs, Tensor training = null, Tensor state = null)
         {
             Tensor outputs = null;
 
diff --git a/src/TensorFlowNET.Core/Keras/Layers/Conv.cs b/src/TensorFlowNET.Core/Keras/Layers/Conv.cs
index 6a7c58cc..ad233d6b 100644
--- a/src/TensorFlowNET.Core/Keras/Layers/Conv.cs
+++ b/src/TensorFlowNET.Core/Keras/Layers/Conv.cs
@@ -108,7 +108,7 @@ namespace Tensorflow.Keras.Layers
             built = true;
         }
 
-        protected override (Tensor, Tensor) call(Tensor inputs, Tensor training = null)
+        protected override (Tensor, Tensor) call(Tensor inputs, Tensor training = null, Tensor state = null)
         {
             var outputs = _convolution_op.__call__(inputs, kernel);
             if (use_bias)
diff --git a/src/TensorFlowNET.Core/Keras/Layers/Dense.cs b/src/TensorFlowNET.Core/Keras/Layers/Dense.cs
index 212035cb..74778873 100644
--- a/src/TensorFlowNET.Core/Keras/Layers/Dense.cs
+++ b/src/TensorFlowNET.Core/Keras/Layers/Dense.cs
@@ -72,7 +72,7 @@ namespace Tensorflow.Keras.Layers
             built = true;
         }
 
-        protected override (Tensor, Tensor) call(Tensor inputs, Tensor training = null)
+        protected override (Tensor, Tensor) call(Tensor inputs, Tensor training = null, Tensor state = null)
         {
             Tensor outputs = null;
             var rank = inputs.rank;
diff --git a/src/TensorFlowNET.Core/Keras/Layers/Embedding.cs b/src/TensorFlowNET.Core/Keras/Layers/Embedding.cs
index f15c01b8..95544d36 100644
--- a/src/TensorFlowNET.Core/Keras/Layers/Embedding.cs
+++ b/src/TensorFlowNET.Core/Keras/Layers/Embedding.cs
@@ -50,7 +50,7 @@ namespace Tensorflow.Keras.Layers
             built = true;
         }
 
-        protected override (Tensor, Tensor) call(Tensor inputs, Tensor training = null)
+        protected override (Tensor, Tensor) call(Tensor inputs, Tensor training = null, Tensor state = null)
         {
             var dtype = inputs.dtype;
             if (dtype != tf.int32 && dtype != tf.int64)
diff --git a/src/TensorFlowNET.Core/Keras/Layers/Layer.cs b/src/TensorFlowNET.Core/Keras/Layers/Layer.cs
index 46d45862..d7d7e31a 100644
--- a/src/TensorFlowNET.Core/Keras/Layers/Layer.cs
+++ b/src/TensorFlowNET.Core/Keras/Layers/Layer.cs
@@ -52,6 +52,7 @@ namespace Tensorflow.Keras.Layers
         protected InputSpec input_spec;
         protected bool supports_masking;
         protected List<VariableV1> _trainable_weights;
+        protected List<VariableV1> _non_trainable_weights;
         private string _name;
         public string name => _name;
         protected string _base_name;
@@ -84,6 +85,7 @@ namespace Tensorflow.Keras.Layers
 
             _init_set_name(name);
             _trainable_weights = new List<VariableV1>();
+            _non_trainable_weights = new List<VariableV1>();
             _compute_previous_mask = false;
             _updates = new List<Operation>();
 
@@ -103,6 +105,7 @@ namespace Tensorflow.Keras.Layers
 
         public (Tensor, Tensor) __call__(Tensor[] inputs,
             Tensor training = null,
+            Tensor state = null,
             VariableScope scope = null)
         {
             var input_list = inputs;
@@ -139,7 +142,9 @@ namespace Tensorflow.Keras.Layers
                     // overridden).
                     _maybe_build(inputs[0]);
 
-                    (input, outputs) = call(inputs[0], training: training);
+                    (input, outputs) = call(inputs[0], 
+                        training: training,
+                        state: state);
                     (input, outputs) = _set_connectivity_metadata_(input, outputs);
                     _handle_activity_regularization(inputs[0], outputs);
                     _set_mask_metadata(inputs[0], outputs, null);
@@ -173,7 +178,7 @@ namespace Tensorflow.Keras.Layers
             return null;
         }
 
-        protected virtual (Tensor, Tensor) call(Tensor inputs, Tensor training = null)
+        protected virtual (Tensor, Tensor) call(Tensor inputs, Tensor training = null, Tensor state = null)
         {
             return (inputs, inputs);
         }
@@ -233,7 +238,10 @@ namespace Tensorflow.Keras.Layers
                 initializer: initializer,
                 trainable: trainable.Value);
             //backend.track_variable(variable);
-            _trainable_weights.Add(variable);
+            if (trainable == true)
+                _trainable_weights.Add(variable);
+            else
+                _non_trainable_weights.Add(variable);
 
             return variable;
         }
diff --git a/src/TensorFlowNET.Core/Keras/Layers/Pooling2D.cs b/src/TensorFlowNET.Core/Keras/Layers/Pooling2D.cs
index e9008543..81d57abe 100644
--- a/src/TensorFlowNET.Core/Keras/Layers/Pooling2D.cs
+++ b/src/TensorFlowNET.Core/Keras/Layers/Pooling2D.cs
@@ -43,7 +43,7 @@ namespace Tensorflow.Keras.Layers
             this.input_spec = new InputSpec(ndim: 4);
         }
 
-        protected override (Tensor, Tensor) call(Tensor inputs, Tensor training = null)
+        protected override (Tensor, Tensor) call(Tensor inputs, Tensor training = null, Tensor state = null)
         {
             int[] pool_shape;
             if (data_format == "channels_last")
diff --git a/src/TensorFlowNET.Core/Layers/Layer.cs b/src/TensorFlowNET.Core/Layers/Layer.cs
index 2ea427c3..d7cda786 100644
--- a/src/TensorFlowNET.Core/Layers/Layer.cs
+++ b/src/TensorFlowNET.Core/Layers/Layer.cs
@@ -43,6 +43,7 @@ namespace Tensorflow.Layers
 
             // Avoid an incorrect lint error
             _trainable_weights = new List<VariableV1>();
+            _non_trainable_weights = new List<VariableV1>();
             this.built = false;
             _keras_style = false;
         }
@@ -54,6 +55,7 @@ namespace Tensorflow.Layers
 
         public (Tensor, Tensor) __call__(Tensor inputs,
             Tensor training = null,
+            Tensor state = null,
             VariableScope scope = null)
         {
             _set_scope(scope);
@@ -76,7 +78,9 @@ namespace Tensorflow.Layers
             {
                 _current_scope = scope2;
                 // Actually call layer
-                outputs = base.__call__(new Tensor[] { inputs }, training: training);
+                outputs = base.__call__(new Tensor[] { inputs }, 
+                    training: training,
+                    state: state);
             });
 
 
@@ -121,6 +125,11 @@ namespace Tensorflow.Layers
             Graph init_graph = null;
             VariableV1[] existing_variables = null;
 
+            if (synchronization == VariableSynchronization.OnRead)
+                trainable = false;
+            else if (!trainable.HasValue)
+                trainable = true;
+
             if (default_graph.building_function)
             {
                 throw new NotImplementedException("add_weight");
diff --git a/src/TensorFlowNET.Core/Operations/BasicRNNCell.cs b/src/TensorFlowNET.Core/Operations/BasicRNNCell.cs
index 9911212b..fdcc03ea 100644
--- a/src/TensorFlowNET.Core/Operations/BasicRNNCell.cs
+++ b/src/TensorFlowNET.Core/Operations/BasicRNNCell.cs
@@ -66,7 +66,7 @@ namespace Tensorflow
             built = true;
         }
 
-        protected override (Tensor, Tensor) call(Tensor inputs, Tensor state = null)
+        protected override (Tensor, Tensor) call(Tensor inputs, Tensor training = null, Tensor state = null)
         {
             // Most basic RNN: output = new_state = act(W * input + U * state + B).
             var concat = array_ops.concat(new[] { inputs, state }, 1);
diff --git a/src/TensorFlowNET.Core/Operations/ControlFlows/WhileContext.cs b/src/TensorFlowNET.Core/Operations/ControlFlows/WhileContext.cs
index 1d071856..715c68c6 100644
--- a/src/TensorFlowNET.Core/Operations/ControlFlows/WhileContext.cs
+++ b/src/TensorFlowNET.Core/Operations/ControlFlows/WhileContext.cs
@@ -307,12 +307,6 @@ namespace Tensorflow.Operations
 
         protected override void _AddOpInternal(Operation op)
         {
-            if(op.name == "rnn/while/basic_rnn_cell/MatMul" ||
-                op.name == "rnn/while/TensorArrayReadV3")
-            {
-
-            }
-
             Operation[] external_inputs = new Operation[0];
             if (op.inputs.Length == 0)
             {
@@ -412,10 +406,12 @@ namespace Tensorflow.Operations
                 }
 
                 if (_outer_context != null)
-                {
                     result = _outer_context.AddValue(val);
-                }
 
+                if (tf.get_default_graph()._nodes_by_name.Count >= 83)
+                {
+
+                }
                 // Create an Enter to make `result` known to this loop context.
                 Tensor enter = null;
                 tf_with(ops.control_dependencies(null), delegate
diff --git a/src/TensorFlowNET.Core/Operations/Initializers/VarianceScaling.cs b/src/TensorFlowNET.Core/Operations/Initializers/VarianceScaling.cs
index e1ac0204..636b1451 100644
--- a/src/TensorFlowNET.Core/Operations/Initializers/VarianceScaling.cs
+++ b/src/TensorFlowNET.Core/Operations/Initializers/VarianceScaling.cs
@@ -16,6 +16,7 @@
 
 using System;
 using System.Linq;
+using static Tensorflow.Binding;
 
 namespace Tensorflow.Operations.Initializers
 {
diff --git a/src/TensorFlowNET.Core/Operations/NnOps/rnn.cs b/src/TensorFlowNET.Core/Operations/NnOps/rnn.cs
index 41a4622a..a8a0e0b9 100644
--- a/src/TensorFlowNET.Core/Operations/NnOps/rnn.cs
+++ b/src/TensorFlowNET.Core/Operations/NnOps/rnn.cs
@@ -214,7 +214,7 @@ namespace Tensorflow.Operations
                 if (sequence_length != null)
                     throw new NotImplementedException("sequence_length != null");
                 else
-                    a = cell.__call__(input_t_t, state1);
+                    a = cell.__call__(input_t_t, state: state1);
 
                 return item;
             };
diff --git a/src/TensorFlowNET.Core/Operations/Operation.Control.cs b/src/TensorFlowNET.Core/Operations/Operation.Control.cs
index 8e660797..9f0cb9a5 100644
--- a/src/TensorFlowNET.Core/Operations/Operation.Control.cs
+++ b/src/TensorFlowNET.Core/Operations/Operation.Control.cs
@@ -32,9 +32,7 @@ namespace Tensorflow
         public void _control_flow_post_processing()
         {
             foreach(Tensor input_tensor in inputs)
-            {
                 control_flow_util.CheckInputFromValidContext(this, input_tensor.op);
-            }
 
             if (_control_flow_context != null)
                 _control_flow_context.AddOp(this);
diff --git a/src/TensorFlowNET.Core/Operations/Operation.cs b/src/TensorFlowNET.Core/Operations/Operation.cs
index 8bdaaa7b..d5068f2e 100644
--- a/src/TensorFlowNET.Core/Operations/Operation.cs
+++ b/src/TensorFlowNET.Core/Operations/Operation.cs
@@ -78,6 +78,7 @@ namespace Tensorflow
 #if SERIALIZABLE
         [JsonIgnore]
 #endif
+        bool _is_stateful;
         public NodeDef node_def
         {
             get
@@ -173,6 +174,8 @@ namespace Tensorflow
                 }
             }
 
+            _id_value = _graph._next_id();
+
             // Dict mapping op name to file and line information for op colocation
             // context managers.
             _control_flow_context = graph._get_control_flow_context();
@@ -184,6 +187,8 @@ namespace Tensorflow
             var grouped_inputs = _reconstruct_sequence_inputs(op_def, inputs, node_def.Attr);
             _handle = ops._create_c_op(g, node_def, grouped_inputs, control_input_ops.ToArray());
 
+            _is_stateful = op_def.IsStateful;
+
             // Initialize self._outputs.
             output_types = new TF_DataType[NumOutputs];
             for (int i = 0; i < NumOutputs; i++)
diff --git a/src/TensorFlowNET.Core/Operations/random_ops.py.cs b/src/TensorFlowNET.Core/Operations/random_ops.py.cs
index 9251f867..be4aef55 100644
--- a/src/TensorFlowNET.Core/Operations/random_ops.py.cs
+++ b/src/TensorFlowNET.Core/Operations/random_ops.py.cs
@@ -71,7 +71,7 @@ namespace Tensorflow
             return tf_with(ops.name_scope(name, "random_uniform", new { shape, minval, maxval }), scope =>
             {
                 name = scope;
-                var tensorShape = _ShapeTensor(shape);
+                var tensorShape = tensor_util.shape_tensor(shape);
                 var minTensor = ops.convert_to_tensor(minval, dtype: dtype, name: "min");
                 var maxTensor = ops.convert_to_tensor(maxval, dtype: dtype, name: "max");
                 var rnd = gen_random_ops.random_uniform(tensorShape, dtype);
diff --git a/src/TensorFlowNET.Core/Tensors/tensor_util.cs b/src/TensorFlowNET.Core/Tensors/tensor_util.cs
index 142afe06..0989db4f 100644
--- a/src/TensorFlowNET.Core/Tensors/tensor_util.cs
+++ b/src/TensorFlowNET.Core/Tensors/tensor_util.cs
@@ -335,5 +335,10 @@ namespace Tensorflow
 
             return shape;
         }
+
+        public static Tensor shape_tensor(int[] shape)
+        {
+            return ops.convert_to_tensor(shape, dtype: TF_DataType.TF_INT32, name: "shape");
+        }
     }
 }
diff --git a/src/TensorFlowNET.Core/Variables/RefVariable.cs b/src/TensorFlowNET.Core/Variables/RefVariable.cs
index 4b0a35fb..c79c5b7f 100644
--- a/src/TensorFlowNET.Core/Variables/RefVariable.cs
+++ b/src/TensorFlowNET.Core/Variables/RefVariable.cs
@@ -133,66 +133,69 @@ namespace Tensorflow
             if (trainable && !collections.Contains(tf.GraphKeys.TRAINABLE_VARIABLES))
                 collections.Add(tf.GraphKeys.TRAINABLE_VARIABLES);
 
-            ops.init_scope();
-            var values = init_from_fn ? new object[0] : new object[] { initial_value };
-            tf_with(ops.name_scope(name, "Variable", values), scope =>
+            tf_with(ops.init_scope2(), delegate
             {
-                name = scope;
-                if (init_from_fn)
+                var values = init_from_fn ? new object[0] : new object[] { initial_value };
+                tf_with(ops.name_scope(name, "Variable", values), scope =>
                 {
-                    // Use attr_scope and device(None) to simulate the behavior of
-                    // colocate_with when the variable we want to colocate with doesn't
-                    // yet exist.
-                    string true_name = ops.name_from_scope_name(name);
-                    var attr = new AttrValue
+                    name = scope;
+
+                    if (init_from_fn)
                     {
-                        List = new AttrValue.Types.ListValue()
-                    };
-                    attr.List.S.Add(ByteString.CopyFromUtf8($"loc:{true_name}"));
-                    tf_with(ops.name_scope("Initializer"), scope2 =>
+                        // Use attr_scope and device(None) to simulate the behavior of
+                        // colocate_with when the variable we want to colocate with doesn't
+                        // yet exist.
+                        string true_name = ops.name_from_scope_name(name);
+                        var attr = new AttrValue
+                        {
+                            List = new AttrValue.Types.ListValue()
+                        };
+                        attr.List.S.Add(ByteString.CopyFromUtf8($"loc:{true_name}"));
+                        tf_with(ops.name_scope("Initializer"), scope2 =>
+                        {
+                            _initial_value = (initial_value as Func<Tensor>)();
+                            _initial_value = ops.convert_to_tensor(_initial_value, name: "initial_value", dtype: dtype);
+                        });
+                        _variable = state_ops.variable_op_v2(_initial_value.shape, _initial_value.dtype.as_base_dtype(), name: name);
+                    }
+                    // Or get the initial value from a Tensor or Python object.
+                    else
                     {
-                        _initial_value = (initial_value as Func<Tensor>)();
-                        _initial_value = ops.convert_to_tensor(_initial_value, name: "initial_value", dtype: dtype);
-                    });
-                    _variable = state_ops.variable_op_v2(_initial_value.shape, _initial_value.dtype.as_base_dtype(), name: name);
-                }
-                // Or get the initial value from a Tensor or Python object.
-                else
-                {
-                    _initial_value = ops.convert_to_tensor(initial_value, name: "initial_value", dtype: dtype);
+                        _initial_value = ops.convert_to_tensor(initial_value, name: "initial_value", dtype: dtype);
 
-                    var shape = _initial_value.shape;
-                    dtype = _initial_value.dtype;
-                    _variable = gen_state_ops.variable_v2(shape, dtype.as_base_dtype(), scope);
-                }
+                        var shape = _initial_value.shape;
+                        dtype = _initial_value.dtype;
+                        _variable = gen_state_ops.variable_v2(shape, dtype.as_base_dtype(), scope);
+                    }
 
-                // Manually overrides the variable's shape with the initial value's.
-                if (validate_shape)
-                {
-                    var initial_value_shape = _initial_value.TensorShape;
-                    if (!initial_value_shape.is_fully_defined())
-                        throw new ValueError($"initial_value must have a shape specified: {_initial_value}");
-                }
+                    // Manually overrides the variable's shape with the initial value's.
+                    if (validate_shape)
+                    {
+                        var initial_value_shape = _initial_value.TensorShape;
+                        if (!initial_value_shape.is_fully_defined())
+                            throw new ValueError($"initial_value must have a shape specified: {_initial_value}");
+                    }
 
-                // If 'initial_value' makes use of other variables, make sure we don't
-                // have an issue if these other variables aren't initialized first by
-                // using their initialized_value() method.
-                var _initial_value2 = _try_guard_against_uninitialized_dependencies(name, _initial_value);
+                    // If 'initial_value' makes use of other variables, make sure we don't
+                    // have an issue if these other variables aren't initialized first by
+                    // using their initialized_value() method.
+                    var _initial_value2 = _try_guard_against_uninitialized_dependencies(name, _initial_value);
 
-                _initializer_op = gen_state_ops.assign(_variable, _initial_value2, validate_shape).op;
+                    _initializer_op = gen_state_ops.assign(_variable, _initial_value2, validate_shape).op;
 
-                if (!String.IsNullOrEmpty(caching_device))
-                {
+                    if (!String.IsNullOrEmpty(caching_device))
+                    {
 
-                }
-                else
-                {
-                    ops.colocate_with(_initializer_op);
+                    }
+                    else
+                    {
+                        ops.colocate_with(_initializer_op);
 
-                    _snapshot = gen_array_ops.identity(_variable, name = "read");
-                }
+                        _snapshot = gen_array_ops.identity(_variable, name = "read");
+                    }
 
-                ops.add_to_collections(collections, this as VariableV1);
+                    ops.add_to_collections(collections, this as VariableV1);
+                });
             });
         }
 
diff --git a/src/TensorFlowNET.Core/ops.cs b/src/TensorFlowNET.Core/ops.cs
index 3549b07e..02417594 100644
--- a/src/TensorFlowNET.Core/ops.cs
+++ b/src/TensorFlowNET.Core/ops.cs
@@ -186,12 +186,7 @@ namespace Tensorflow
         /// operations constructed within the context.
         /// </returns>
         public static _ControlDependenciesController control_dependencies(object[] control_inputs)
-        {
-            return get_default_graph().control_dependencies(control_inputs);
-        }
-
-        public static _ControlDependenciesController control_dependencies(ITensorOrOperation[] control_inputs)
-            => control_dependencies(control_inputs == null ? null : control_inputs.OfType<object>().ToArray());
+            => get_default_graph().control_dependencies(control_inputs);
 
         /// <summary>
         /// Creates a TF_Operation.
@@ -212,9 +207,9 @@ namespace Tensorflow
             {
                 var op_desc = graph.NewOperation(node_def.Op, node_def.Name);
 
-                //TODO: Implement TF_SetDevice
-                //if node_def.device:
-                //    c_api.TF_SetDevice(op_desc, compat.as_str(node_def.device))
+                if (!string.IsNullOrEmpty(node_def.Device))
+                    c_api.TF_SetDevice(op_desc, node_def.Device);
+
                 // Add inputs
                 foreach (var op_input in inputs)
                 {
@@ -310,6 +305,22 @@ namespace Tensorflow
             });
         }
 
+        public static IObjectLife init_scope2()
+        {
+            // Retrieve the active name scope: entering an `init_scope` preserves
+            // the name scope of the current context.
+            var default_graph = get_default_graph();
+            var scope = default_graph.get_name_scope();
+            if (!String.IsNullOrEmpty(scope) && !scope.EndsWith("/"))
+                // Names that end with trailing slashes are treated by `name_scope` as
+                // absolute.
+                scope += "/";
+            // inner_device_stack = default_graph._device_function_stack
+            // var outer_context = default_graph.as_default;
+
+            return ops.control_dependencies(null);
+        }
+
         private static int uid_number = 0;
 
         /// <summary>