override graph

src/TensorFlowNET.Core/Sessions/_ElementFetchMapper.cs

@@ -28,9 +28,9 @@ namespace Tensorflow
     {
         private Func<List<NDArray>, object> _contraction_fn;
 
-        public _ElementFetchMapper(object[] fetches, Func<List<NDArray>, object> contraction_fn)
+        public _ElementFetchMapper(object[] fetches, Func<List<NDArray>, object> contraction_fn, Graph graph = null)
         {
-            var g = ops.get_default_graph();
+            var g = graph ?? ops.get_default_graph();
 
             foreach(var fetch in fetches)
             {

src/TensorFlowNET.Core/Sessions/_FetchHandler.cs

@@ -34,7 +34,7 @@ namespace Tensorflow
 
         public _FetchHandler(Graph graph, object fetches, Dictionary<object, object> feeds = null, Action feed_handles = null)
         {
-            _fetch_mapper = _FetchMapper.for_fetch(fetches);
+            _fetch_mapper = _FetchMapper.for_fetch(fetches, graph: graph);
             foreach(var fetch in _fetch_mapper.unique_fetches())
             {
                 switch (fetch)

src/TensorFlowNET.Core/Sessions/_FetchMapper.cs

@@ -25,7 +25,7 @@ namespace Tensorflow
     {
         protected List<ITensorOrOperation> _unique_fetches = new List<ITensorOrOperation>();
         protected List<int[]> _value_indices = new List<int[]>();
-        public static _FetchMapper for_fetch(object fetch)
+        public static _FetchMapper for_fetch(object fetch, Graph graph = null)
         {
             var fetches = fetch.GetType().IsArray ? (object[])fetch : new object[] { fetch };
 
@@ -34,7 +34,7 @@ namespace Tensorflow
             if (fetch.GetType().IsArray)
                 return new _ListFetchMapper(fetches);
             else
-                return new _ElementFetchMapper(fetches, (List<NDArray> fetched_vals) => fetched_vals[0]);
+                return new _ElementFetchMapper(fetches, (List<NDArray> fetched_vals) => fetched_vals[0], graph: graph);
         }
 
         public virtual NDArray[] build_results(List<NDArray> values)