shengc/tf-han

TensorFlow Implementation For [Hierarchical Attention Networks for Document Classification](http://www.cs.cmu.edu/~./hovy/papers/16HLT-hierarchical-attention-networks.pdf)

tf-han's Issues

generalization performance is bad

I have corrected an implementation error that did not treat sentences from the same document as a coherent sequence. However the generalization performance on validation set remains to be bad.

mini batch version is currently broken

Calling method _make_graph_batch will end up with the following error. I suspected TensorFlow does not support the nested while_loop function in this case. I suspected this is related to tensorflow/tensorflow#593. I think I will open an issue for this on TensorFlow's issue page too.

INFO:tensorflow:Cannot use 'words_lstm/map/while/bidirectional_rnn/fw/fw/strided_slice_1' as input to 'gradients/words_lstm/map/while/bidirectional_rnn/fw/fw/while/TensorArrayWrite/TensorArrayWriteV3_grad/TensorArrayReadV3/f_acc' because 'words_lstm/map/while/bidirectional_rnn/fw/fw/strided_slice_1' is in a while loop.

gradients/words_lstm/map/while/bidirectional_rnn/fw/fw/while/TensorArrayWrite/TensorArrayWriteV3_grad/TensorArrayReadV3/f_acc while context: None
words_lstm/map/while/bidirectional_rnn/fw/fw/strided_slice_1 while context: words_lstm/map/while/while_context

Traceback for gradients/words_lstm/map/while/bidirectional_rnn/fw/fw/while/TensorArrayWrite/TensorArrayWriteV3_grad/TensorArrayReadV3/f_acc:
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel_launcher.py", line 16, in <module>
    app.launch_new_instance()
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/traitlets/config/application.py", line 658, in launch_instance
    app.start()
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/kernelapp.py", line 486, in start
    self.io_loop.start()
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tornado/ioloop.py", line 888, in start
    handler_func(fd_obj, events)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tornado/stack_context.py", line 277, in null_wrapper
    return fn(*args, **kwargs)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/zmq/eventloop/zmqstream.py", line 450, in _handle_events
    self._handle_recv()
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/zmq/eventloop/zmqstream.py", line 480, in _handle_recv
    self._run_callback(callback, msg)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/zmq/eventloop/zmqstream.py", line 432, in _run_callback
    callback(*args, **kwargs)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tornado/stack_context.py", line 277, in null_wrapper
    return fn(*args, **kwargs)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/kernelbase.py", line 283, in dispatcher
    return self.dispatch_shell(stream, msg)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/kernelbase.py", line 233, in dispatch_shell
    handler(stream, idents, msg)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/kernelbase.py", line 399, in execute_request
    user_expressions, allow_stdin)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/ipkernel.py", line 208, in do_execute
    res = shell.run_cell(code, store_history=store_history, silent=silent)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/zmqshell.py", line 537, in run_cell
    return super(ZMQInteractiveShell, self).run_cell(*args, **kwargs)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2728, in run_cell
    interactivity=interactivity, compiler=compiler, result=result)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2856, in run_ast_nodes
    if self.run_code(code, result):
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2910, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-11-53b266ea81e8>", line 3, in <module>
    model._make_graph_batch(tf.Graph())
  File "<ipython-input-9-f1807c298dcc>", line 47, in _make_graph_batch
    training_op = tf.train.AdamOptimizer(learning_rate=0.01).minimize(loss)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/training/optimizer.py", line 355, in minimize
    grad_loss=grad_loss)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/training/optimizer.py", line 456, in compute_gradients
    colocate_gradients_with_ops=colocate_gradients_with_ops)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gradients_impl.py", line 609, in gradients
    grad_scope, op, func_call, lambda: grad_fn(op, *out_grads))
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gradients_impl.py", line 375, in _MaybeCompile
    return grad_fn()  # Exit early
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gradients_impl.py", line 609, in <lambda>
    grad_scope, op, func_call, lambda: grad_fn(op, *out_grads))
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/tensor_array_grad.py", line 131, in _TensorArrayWriteGrad
    grad = g.read(index)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/tensor_array_ops.py", line 859, in read
    return self._implementation.read(index, name=name)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/tensor_array_ops.py", line 259, in read
    name=name)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gen_data_flow_ops.py", line 4498, in _tensor_array_read_v3
    dtype=dtype, name=name)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/op_def_library.py", line 787, in _apply_op_helper
    op_def=op_def)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/ops.py", line 3160, in create_op
    op_def=op_def)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/ops.py", line 1674, in __init__
    self._control_flow_context.AddOp(self)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py", line 2251, in AddOp
    self._AddOpInternal(op)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py", line 2274, in _AddOpInternal
    real_x = self.AddValue(x)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py", line 2207, in AddValue
    real_val = grad_ctxt.grad_state.GetRealValue(val)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py", line 1050, in GetRealValue
    history_value = cur_grad_state.AddForwardAccumulator(cur_value)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py", line 908, in AddForwardAccumulator
    name="f_acc")
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gen_data_flow_ops.py", line 3578, in _stack_v2
    stack_name=stack_name, name=name)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/op_def_library.py", line 787, in _apply_op_helper
    op_def=op_def)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/ops.py", line 3160, in create_op
    op_def=op_def)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/ops.py", line 1625, in __init__
    self._traceback = self._graph._extract_stack()  # pylint: disable=protected-access

Traceback for words_lstm/map/while/bidirectional_rnn/fw/fw/strided_slice_1:
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel_launcher.py", line 16, in <module>
    app.launch_new_instance()
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/traitlets/config/application.py", line 658, in launch_instance
    app.start()
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/kernelapp.py", line 486, in start
    self.io_loop.start()
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tornado/ioloop.py", line 888, in start
    handler_func(fd_obj, events)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tornado/stack_context.py", line 277, in null_wrapper
    return fn(*args, **kwargs)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/zmq/eventloop/zmqstream.py", line 450, in _handle_events
    self._handle_recv()
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/zmq/eventloop/zmqstream.py", line 480, in _handle_recv
    self._run_callback(callback, msg)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/zmq/eventloop/zmqstream.py", line 432, in _run_callback
    callback(*args, **kwargs)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tornado/stack_context.py", line 277, in null_wrapper
    return fn(*args, **kwargs)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/kernelbase.py", line 283, in dispatcher
    return self.dispatch_shell(stream, msg)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/kernelbase.py", line 233, in dispatch_shell
    handler(stream, idents, msg)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/kernelbase.py", line 399, in execute_request
    user_expressions, allow_stdin)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/ipkernel.py", line 208, in do_execute
    res = shell.run_cell(code, store_history=store_history, silent=silent)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/ipykernel/zmqshell.py", line 537, in run_cell
    return super(ZMQInteractiveShell, self).run_cell(*args, **kwargs)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2728, in run_cell
    interactivity=interactivity, compiler=compiler, result=result)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2856, in run_ast_nodes
    if self.run_code(code, result):
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2910, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-11-53b266ea81e8>", line 3, in <module>
    model._make_graph_batch(tf.Graph())
  File "<ipython-input-9-f1807c298dcc>", line 26, in _make_graph_batch
    outputs = tf.map_fn(fn, (embedded, words_length), dtype=tf.float32)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/functional_ops.py", line 409, in map_fn
    swap_memory=swap_memory)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py", line 2934, in while_loop
    result = loop_context.BuildLoop(cond, body, loop_vars, shape_invariants)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py", line 2720, in BuildLoop
    pred, body, original_loop_vars, loop_vars, shape_invariants)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py", line 2662, in _BuildLoop
    body_result = body(*packed_vars_for_body)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/functional_ops.py", line 399, in compute
    packed_fn_values = fn(packed_values)
  File "<ipython-input-9-f1807c298dcc>", line 24, in fn
    (outputs_fw, outputs_bw), _ =                         tf.nn.bidirectional_dynamic_rnn(cell_fw, cell_bw, inp[0], sequence_length=inp[1], dtype=tf.float32)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/rnn.py", line 414, in bidirectional_dynamic_rnn
    time_major=time_major, scope=fw_scope)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/rnn.py", line 629, in dynamic_rnn
    dtype=dtype)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/rnn.py", line 688, in _dynamic_rnn_loop
    time_steps = input_shape[0]
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/array_ops.py", line 573, in _slice_helper
    name=name)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/array_ops.py", line 737, in strided_slice
    shrink_axis_mask=shrink_axis_mask)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gen_array_ops.py", line 5501, in strided_slice
    name=name)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/op_def_library.py", line 787, in _apply_op_helper
    op_def=op_def)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/ops.py", line 3160, in create_op
    op_def=op_def)
  File "/Users/shengc/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/ops.py", line 1625, in __init__
    self._traceback = self._graph._extract_stack()  # pylint: disable=protected-access


---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gradients_impl.py in _MaybeCompile(scope, op, func, grad_fn)
    369     try:
--> 370       xla_compile = op.get_attr("_XlaCompile")
    371       xla_separate_compiled_gradients = op.get_attr(

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/ops.py in get_attr(self, name)
   2172         raise ValueError(
-> 2173             "No attr named '" + name + "' in " + str(self._node_def))
   2174       x = self._node_def.attr[name]

ValueError: No attr named '_XlaCompile' in name: "words_lstm/map/while/bidirectional_rnn/fw/fw/while/TensorArrayWrite/TensorArrayWriteV3"
op: "TensorArrayWriteV3"
input: "words_lstm/map/while/bidirectional_rnn/fw/fw/while/TensorArrayWrite/TensorArrayWriteV3/Enter"
input: "words_lstm/map/while/bidirectional_rnn/fw/fw/while/Identity_1"
input: "words_lstm/map/while/bidirectional_rnn/fw/fw/while/Select"
input: "words_lstm/map/while/bidirectional_rnn/fw/fw/while/Identity_2"
attr {
  key: "T"
  value {
    type: DT_FLOAT
  }
}
attr {
  key: "_class"
  value {
    list {
      s: "loc:@words_lstm/map/while/bidirectional_rnn/fw/fw/while/gru_cell/add"
    }
  }
}


During handling of the above exception, another exception occurred:

ValueError                                Traceback (most recent call last)
<ipython-input-11-53b266ea81e8> in <module>()
      1 embedding_matrix = np.random.randn(len(embeddings) + 1, 10)
      2 model = HierarchicalAttentionNetwork(embedding_matrix, len(tag_to_ix), hidden_dim=10)
----> 3 model._make_graph_batch(tf.Graph())
      4 #model.fit(train_words_seq, train_length_seq, train_label_seq, num_epochs=20, model='models/han.ckpt')

<ipython-input-9-f1807c298dcc> in _make_graph_batch(self, graph)
     45 #             loss = tf.nn.sparse_softmax_cross_entropy_with_logits(logits=logits, labels=labels)
     46 #             loss = tf.reduce_mean(loss)
---> 47             training_op = tf.train.AdamOptimizer(learning_rate=0.01).minimize(loss)
     48             return words, words_length, sentences_length, labels, logits, loss, training_op
     49     def _make_graph(self, graph):

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/training/optimizer.py in minimize(self, loss, global_step, var_list, gate_gradients, aggregation_method, colocate_gradients_with_ops, name, grad_loss)
    353         aggregation_method=aggregation_method,
    354         colocate_gradients_with_ops=colocate_gradients_with_ops,
--> 355         grad_loss=grad_loss)
    356 
    357     vars_with_grad = [v for g, v in grads_and_vars if g is not None]

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/training/optimizer.py in compute_gradients(self, loss, var_list, gate_gradients, aggregation_method, colocate_gradients_with_ops, grad_loss)
    454         gate_gradients=(gate_gradients == Optimizer.GATE_OP),
    455         aggregation_method=aggregation_method,
--> 456         colocate_gradients_with_ops=colocate_gradients_with_ops)
    457     if gate_gradients == Optimizer.GATE_GRAPH:
    458       grads = control_flow_ops.tuple(grads)

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gradients_impl.py in gradients(ys, xs, grad_ys, name, colocate_gradients_with_ops, gate_gradients, aggregation_method, stop_gradients)
    607                 # functions.
    608                 in_grads = _MaybeCompile(
--> 609                     grad_scope, op, func_call, lambda: grad_fn(op, *out_grads))
    610               else:
    611                 # For function call ops, we add a 'SymbolicGradient'

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gradients_impl.py in _MaybeCompile(scope, op, func, grad_fn)
    373       xla_scope = op.get_attr("_XlaScope").decode()
    374     except ValueError:
--> 375       return grad_fn()  # Exit early
    376 
    377   if not xla_compile:

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gradients_impl.py in <lambda>()
    607                 # functions.
    608                 in_grads = _MaybeCompile(
--> 609                     grad_scope, op, func_call, lambda: grad_fn(op, *out_grads))
    610               else:
    611                 # For function call ops, we add a 'SymbolicGradient'

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/tensor_array_grad.py in _TensorArrayWriteGrad(op, flow)
    129                                     colocate_with_first_write_call=False)
    130        .grad(source=grad_source, flow=flow))
--> 131   grad = g.read(index)
    132   return [None, None, grad, flow]
    133 

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/tensor_array_ops.py in read(self, index, name)
    857       The tensor at index `index`.
    858     """
--> 859     return self._implementation.read(index, name=name)
    860 
    861   @tf_should_use.should_use_result

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/tensor_array_ops.py in read(self, index, name)
    257         flow_in=self._flow,
    258         dtype=self._dtype,
--> 259         name=name)
    260     if self._element_shape:
    261       value.set_shape(self._element_shape[0].dims)

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gen_data_flow_ops.py in _tensor_array_read_v3(handle, index, flow_in, dtype, name)
   4496     _, _, _op = _op_def_lib._apply_op_helper(
   4497         "TensorArrayReadV3", handle=handle, index=index, flow_in=flow_in,
-> 4498         dtype=dtype, name=name)
   4499     _result = _op.outputs[:]
   4500     _inputs_flat = _op.inputs

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/op_def_library.py in _apply_op_helper(self, op_type_name, name, **keywords)
    785         op = g.create_op(op_type_name, inputs, output_types, name=scope,
    786                          input_types=input_types, attrs=attr_protos,
--> 787                          op_def=op_def)
    788       return output_structure, op_def.is_stateful, op
    789 

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/ops.py in create_op(self, op_type, inputs, dtypes, input_types, name, attrs, op_def, compute_shapes, compute_device)
   3158         input_types=input_types,
   3159         original_op=self._default_original_op,
-> 3160         op_def=op_def)
   3161     self._create_op_helper(ret, compute_shapes=compute_shapes,
   3162                            compute_device=compute_device)

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/ops.py in __init__(self, node_def, g, inputs, output_types, control_inputs, input_types, original_op, op_def)
   1672       control_flow_util.CheckInputFromValidContext(self, input_tensor.op)
   1673     if self._control_flow_context is not None:
-> 1674       self._control_flow_context.AddOp(self)
   1675     self._recompute_node_def()
   1676 

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py in AddOp(self, op)
   2249             op_input_ctxt._AddOpInternal(op)
   2250             return
-> 2251     self._AddOpInternal(op)
   2252 
   2253   def _AddOpInternal(self, op):

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py in _AddOpInternal(self, op)
   2272       for index in range(len(op.inputs)):
   2273         x = op.inputs[index]
-> 2274         real_x = self.AddValue(x)
   2275         if real_x != x:
   2276           op._update_input(index, real_x)

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py in AddValue(self, val)
   2205               forward_ctxt = forward_ctxt.GetWhileContext()
   2206           if forward_ctxt == grad_ctxt.grad_state.forward_context:
-> 2207             real_val = grad_ctxt.grad_state.GetRealValue(val)
   2208             self._external_values[val.name] = real_val
   2209             return real_val

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py in GetRealValue(self, value)
   1048           # Record the history of this value in forward_ctxt.
   1049           self._grad_context.Exit()
-> 1050           history_value = cur_grad_state.AddForwardAccumulator(cur_value)
   1051           self._grad_context.Enter()
   1052           break

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_ops.py in AddForwardAccumulator(self, value, dead_branch)
    906             max_size=maximum_iterations,
    907             elem_type=value.dtype.base_dtype,
--> 908             name="f_acc")
    909         # pylint: enable=protected-access
    910       if curr_ctxt: curr_ctxt.Exit()

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/gen_data_flow_ops.py in _stack_v2(max_size, elem_type, stack_name, name)
   3576     _, _, _op = _op_def_lib._apply_op_helper(
   3577         "StackV2", max_size=max_size, elem_type=elem_type,
-> 3578         stack_name=stack_name, name=name)
   3579     _result = _op.outputs[:]
   3580     _inputs_flat = _op.inputs

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/op_def_library.py in _apply_op_helper(self, op_type_name, name, **keywords)
    785         op = g.create_op(op_type_name, inputs, output_types, name=scope,
    786                          input_types=input_types, attrs=attr_protos,
--> 787                          op_def=op_def)
    788       return output_structure, op_def.is_stateful, op
    789 

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/ops.py in create_op(self, op_type, inputs, dtypes, input_types, name, attrs, op_def, compute_shapes, compute_device)
   3158         input_types=input_types,
   3159         original_op=self._default_original_op,
-> 3160         op_def=op_def)
   3161     self._create_op_helper(ret, compute_shapes=compute_shapes,
   3162                            compute_device=compute_device)

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/framework/ops.py in __init__(self, node_def, g, inputs, output_types, control_inputs, input_types, original_op, op_def)
   1670     self._control_flow_context = g._get_control_flow_context()  # pylint: disable=protected-access
   1671     for input_tensor in self.inputs:
-> 1672       control_flow_util.CheckInputFromValidContext(self, input_tensor.op)
   1673     if self._control_flow_context is not None:
   1674       self._control_flow_context.AddOp(self)

~/anaconda/envs/py36/lib/python3.6/site-packages/tensorflow/python/ops/control_flow_util.py in CheckInputFromValidContext(op, input_op)
    198         input_op.name, "".join(traceback.format_list(input_op.traceback)))
    199     logging.info(log_msg)
--> 200     raise ValueError(error_msg + " See info log for more details.")

ValueError: Cannot use 'words_lstm/map/while/bidirectional_rnn/fw/fw/strided_slice_1' as input to 'gradients/words_lstm/map/while/bidirectional_rnn/fw/fw/while/TensorArrayWrite/TensorArrayWriteV3_grad/TensorArrayReadV3/f_acc' because 'words_lstm/map/while/bidirectional_rnn/fw/fw/strided_slice_1' is in a while loop. See info log for more details.