LoopVar<T>

src/TensorFlowNET.Core/Operations/ControlFlows/ControlFlowContext.cs

@@ -19,6 +19,7 @@ using System.Collections.Generic;
 using System.Linq;
 using Tensorflow.Operations.ControlFlows;
 using static Tensorflow.ControlFlowContextDef;
+using static Tensorflow.Binding;
 
 namespace Tensorflow.Operations
 {
@@ -72,6 +73,7 @@ namespace Tensorflow.Operations
         public ControlFlowContext()
         {
             _context_stack = new Stack<ControlFlowContext>();
+            _external_values = new Dictionary<string, ITensorOrOperation>();
         }
 
         public string name { get => _name; }
@@ -180,6 +182,11 @@ namespace Tensorflow.Operations
 
         public virtual bool back_prop => throw new NotImplementedException("abstract method");
 
+        /// <summary>
+        /// Add `val` to the current context and its outer context recursively.
+        /// </summary>
+        /// <param name="val"></param>
+        /// <returns></returns>
         public virtual Tensor AddValue(Tensor val)
         {
             // to be overridden
@@ -203,7 +210,25 @@ namespace Tensorflow.Operations
         /// </summary>
         protected virtual void _AddOpInternal(Operation op)
         {
-            
+            if (op.name == "rnn/while/Less")
+            {
+
+            }
+
+            if(op == null)
+            {
+                throw new NotImplementedException("");
+            }
+            else
+            {
+                foreach(var index in range(len(op.inputs)))
+                {
+                    var x = op.inputs[index];
+                    var real_x = AddValue(x);
+                    if (real_x != x)
+                        op._update_input(index, real_x);
+                }
+            }
         }
 
         protected bool OpInContext(Operation op)

src/TensorFlowNET.Core/Operations/ControlFlows/LoopVar.cs

@@ -24,5 +24,10 @@ namespace Tensorflow.Operations
                 elements.Add(Item);
             return elements.ToArray();
         }
+
+        public static implicit operator (Tensor, TItem)(LoopVar<TItem> loopVar)
+        {
+            return (loopVar.Counter, loopVar.Item);
+        }
     }
 }

src/TensorFlowNET.Core/Operations/ControlFlows/WhileContext.cs

@@ -71,6 +71,8 @@ namespace Tensorflow.Operations
             string name)
         {
             _name = ops.get_default_graph().unique_name(name);
+            _maximum_iterations = maximum_iterations;
+            _parallel_iterations = parallel_iterations;
             _back_prop = back_prop;
             _swap_memory = swap_memory;
             _loop_exits = new List<Tensor>();
@@ -107,18 +109,27 @@ namespace Tensorflow.Operations
         /// <summary>
         /// Add the loop termination condition and body to the graph.
         /// </summary>
-        internal Tensor[] BuildLoop<TItem>(Func<Tensor, TItem, Tensor> pred, 
-            Func<Tensor, TItem, LoopVar<TItem>> body,
+        internal Tensor[] BuildLoop<TItem>(Func<LoopVar<TItem>, Tensor> pred, 
+            Func<LoopVar<TItem>, LoopVar<TItem>> body,
             LoopVar<TItem> loop_vars,
-            TensorShape shape_invariants,
+            TensorShape[] shape_invariants,
             bool return_same_structure)
         {
             // Keep original_loop_vars to identify which are TensorArrays
             var original_loop_vars = loop_vars;
             // Convert TensorArrays to their flow variables
+            var loop_vars_tensors = nest.flatten2(loop_vars)
+                .Select(x => _convert_tensorarray_to_flow(x))
+                .ToArray();
+
+            if (shape_invariants == null)
+                shape_invariants = loop_vars_tensors
+                    .Select(x => _get_shape_invariant(x as Tensor))
+                    .ToArray();
+
             Enter();
             var(original_body_result, exit_vars) = _BuildLoop(
-                pred, body, original_loop_vars, loop_vars, shape_invariants);
+                pred, body, original_loop_vars, loop_vars_tensors, shape_invariants);
             Exit();
 
             var flat_result = original_body_result;
@@ -131,7 +142,7 @@ namespace Tensorflow.Operations
             return packed_exit_vars as Tensor[];
         }
 
-        private Tensor _convert_tensorarray_to_flow<TItem>(TItem tensor_or_tensor_array)
+        private Tensor _convert_tensorarray_to_flow(object tensor_or_tensor_array)
         {
             if (tensor_or_tensor_array is TensorArray tensor_array)
                 return tensor_array.flow;
@@ -141,97 +152,116 @@ namespace Tensorflow.Operations
             throw new NotImplementedException("_convert_tensorarray_to_flow");
         }
 
-        private (Tensor[], Tensor[]) _BuildLoop<TItem>(Func<Tensor, TItem, Tensor> pred,
-            Func<Tensor, TItem, LoopVar<TItem>> body,
-            LoopVar<TItem> original_loop_vars,
-            LoopVar<TItem> loop_vars,
-            TensorShape shape_invariants)
+        private TensorShape _get_shape_invariant(Tensor var, int[] shape = null)
         {
-            var flat_loop_vars = original_loop_vars;
+            return var.TensorShape;
+        }
 
-            // Convert TensorArrays to their flow variables
-            var loop_vars_tensor = nest.map_structure(
-                _convert_tensorarray_to_flow,
-                nest.flatten2(loop_vars));
+        /// <summary>
+        /// Add the loop termination condition and body to the graph.
+        /// </summary>
+        /// <typeparam name="TItem"></typeparam>
+        /// <param name="pred"></param>
+        /// <param name="body"></param>
+        /// <param name="original_loop_vars"></param>
+        /// <param name="loop_vars"></param>
+        /// <param name="shape_invariants"></param>
+        /// <returns></returns>
+        private (Tensor[], Tensor[]) _BuildLoop<TItem>(Func<LoopVar<TItem>, Tensor> pred,
+            Func<LoopVar<TItem>, LoopVar<TItem>> body,
+            LoopVar<TItem> original_loop_vars,
+            Tensor[] loop_vars,
+            TensorShape[] shape_invariants)
+        {
+            var flat_loop_vars = nest.flatten2(original_loop_vars)
+                .Select(x => (ITensorOrTensorArray)x)
+                .ToArray();
 
             // Let the context know the loop variables so the loop variables
             // would be added in the outer contexts properly.
-            if (loop_vars is Tensor[] real_vars)
+            _InitializeValues(loop_vars);
+            var real_vars = loop_vars;
+            Tensor[] enter_vars = null;
+            tf_with(ops.control_dependencies(null), delegate
             {
-                _InitializeValues(real_vars);
-                Tensor[] enter_vars = null;
-                tf_with(ops.control_dependencies(null), delegate
-                {
-                    enter_vars = real_vars.Select(x => _Enter(x,
-                        _name,
-                        is_constant: false,
-                        parallel_iterations: _parallel_iterations,
-                        use_input_shape: shape_invariants == null))
-                    .ToArray();
-
-                    foreach (var x in enter_vars)
-                    {
-                        x.graph.prevent_feeding(x);
-                        if (_outer_context != null)
-                            _outer_context.AddInnerOp(x.op);
-                    }
-                });
-
-                // Finds the closest enclosing non-None control pivot.
-                var outer_context = _outer_context;
-                while (outer_context != null)
+                enter_vars = real_vars.Select(x => _Enter(x,
+                    _name,
+                    is_constant: false,
+                    parallel_iterations: _parallel_iterations,
+                    use_input_shape: shape_invariants == null))
+                .ToArray();
+
+                foreach (var x in enter_vars)
                 {
-
+                    x.graph.prevent_feeding(x);
+                    if (_outer_context != null)
+                        _outer_context.AddInnerOp(x.op);
                 }
+            });
 
-                _SetShapeInvariants(real_vars, enter_vars, shape_invariants);
-
-                // Fix the control inputs and control flow context of these enter ops.
-                _FixControlInputsAndContext(enter_vars);
-                _InitializeValues(enter_vars);
-                _loop_enters = enter_vars.ToList();
-
-                var merge_vars = enter_vars
-                    .Select(x => merge(new[] { x, x }))
-                    .ToArray();
+            // Finds the closest enclosing non-None control pivot.
+            var outer_context = _outer_context;
+            object control_pivot = null;
+            while (outer_context != null && control_pivot == null)
+            {
 
-                _pivot_for_pred = merge_vars[0];
+            }
 
-                // Build the graph for pred.
-                var merge_vars_with_tensor_arrays = _convert_flows_to_tensorarrays(flat_loop_vars, merge_vars);
-                // var packed_vars = nest.pack_sequence_as(original_loop_vars, merge_vars_with_tensor_arrays);
-                var c = ops.convert_to_tensor(pred(merge_vars_with_tensor_arrays[0], default(TItem)));
-                _pivot = gen_control_flow_ops.loop_cond(c, name: "LoopCond");
-                var switch_vars = merge_vars.Select(x => _SwitchRefOrTensor(x, _pivot))
-                    .ToArray();
+            if (control_pivot != null)
+            {
 
-                // Build the graph for body.
-                var vars_for_body = switch_vars.Select(x => _Identity(x[1])).ToArray();
-                // Convert TensorArray flow variables inside the context back into
-                // their associated TensorArrays for calling the body.
-                var packed_vars_for_body = _convert_flows_to_tensorarrays(flat_loop_vars, vars_for_body);
-                /*var body_result = body(packed_vars_for_body[0]);
-                var post_summaries = ops.get_collection(tf.GraphKeys._SUMMARY_COLLECTION);
-
-                // Store body_result to keep track of TensorArrays returned by body
-                var original_body_result = new[] { body_result };
-                // Convert TensorArrays returned by body into their flow variables
-                var result = new[] { body_result };
-
-                var next_vars = new List<Tensor>();
-                foreach (var (m, v) in zip(merge_vars, result))
-                    next_vars.Add(_AddNextAndBackEdge(m, v));
-
-                // Add the exit ops.
-                var exit_vars = switch_vars.Select(x => exit(x[0])).ToList();
-                _loop_exits = exit_vars;
-
-                // Exit the loop.
-                // ExitResult(exit_vars);
-                return (original_body_result, exit_vars.ToArray());*/
             }
 
-            throw new NotImplementedException("");
+            _SetShapeInvariants(real_vars, enter_vars, shape_invariants);
+
+            // Fix the control inputs and control flow context of these enter ops.
+            _FixControlInputsAndContext(enter_vars);
+            _InitializeValues(enter_vars);
+            _loop_enters = enter_vars.ToList();
+
+            var merge_vars = enter_vars
+                .Select(x => merge(new[] { x, x }))
+                .ToArray();
+
+            _pivot_for_pred = merge_vars[0];
+
+            // Build the graph for pred.
+            var merge_vars_with_tensor_arrays = _convert_flows_to_tensorarrays(flat_loop_vars, merge_vars);
+            //var packed_vars = nest.pack_sequence_as(original_loop_vars, merge_vars_with_tensor_arrays, expand_composites: true);
+            var packed_vars = new LoopVar<TItem>((Tensor)merge_vars_with_tensor_arrays[0],
+                (TItem)(object)new BodyItemInRnnWhileLoop((Tensor)merge_vars_with_tensor_arrays[1],
+                new[] { (TensorArray)merge_vars_with_tensor_arrays[2] },
+                (Tensor)merge_vars_with_tensor_arrays[3]));
+            var pp = pred(packed_vars);
+            var c = ops.convert_to_tensor(pp);
+            _pivot = gen_control_flow_ops.loop_cond(c, name: "LoopCond");
+            var switch_vars = merge_vars.Select(x => _SwitchRefOrTensor(x, _pivot))
+                .ToArray();
+
+            // Build the graph for body.
+            var vars_for_body = switch_vars.Select(x => _Identity(x[1])).ToArray();
+            // Convert TensorArray flow variables inside the context back into
+            // their associated TensorArrays for calling the body.
+            var packed_vars_for_body = _convert_flows_to_tensorarrays(flat_loop_vars, vars_for_body);
+            var body_result = body(original_loop_vars);
+            var post_summaries = ops.get_collection(tf.GraphKeys._SUMMARY_COLLECTION);
+
+            // Store body_result to keep track of TensorArrays returned by body
+            var original_body_result = new[] { body_result };
+            // Convert TensorArrays returned by body into their flow variables
+            var result = new[] { body_result };
+
+            var next_vars = new List<Tensor>();
+            //foreach (var (m, v) in zip(merge_vars, result))
+                //next_vars.Add(_AddNextAndBackEdge(m, v));
+
+            // Add the exit ops.
+            var exit_vars = switch_vars.Select(x => exit(x[0])).ToList();
+            _loop_exits = exit_vars;
+
+            // Exit the loop.
+            // ExitResult(exit_vars);
+            return (null, exit_vars.ToArray());
         }
 
         private void _FixControlInputsAndContext(Tensor[] enters)
@@ -258,6 +288,23 @@ namespace Tensorflow.Operations
                 _values.Add(x.name);
         }
 
+        public override Tensor AddValue(Tensor val)
+        {
+            var result = val;
+            var new_value = _values.Contains(val.name);
+            new_value &= val.op._get_control_flow_context() != this;
+            if (new_value)
+                throw new NotImplementedException("");
+            else
+            {
+                var actual_val = _external_values.ContainsKey(val.name) ? _external_values[val.name] : null;
+                if (actual_val != null)
+                    result = actual_val as Tensor;
+            }
+
+            return result;
+        }
+
         public override WhileContext GetWhileContext()
         {
             return this;