Tensorflow bidirectional_dynamic_rnn() FailedPreconditionError: Attempting to use uninitialized value BiRNN/FW/LSTMCell/B - tensorflow

Question

I'm getting the above error when attempting to call tf.nn.bidirectional_dynamic_rnn(). I've called tf.global_variables_initializer(). At first I thought it's because I didn't pass in sequence_length to tf.nn.bidirectional_dynamic_rnn(). However, even after I did, it's still shows the same error.
Any idea?
Stacktrace:
Traceback (most recent call last):
File "/Applications/PyCharm CE.app/Contents/helpers/pydev/pydevd.py", line 1580, in <module>
globals = debugger.run(setup['file'], None, None, is_module)
File "/Applications/PyCharm CE.app/Contents/helpers/pydev/pydevd.py", line 964, in run
pydev_imports.execfile(file, globals, locals) # execute the script
File "/Users/Keven/Documents/stanford local/cs224n project/224n-project/bi_lstm_encoder.py", line 49, in <module>
test_bilstm()
File "/Users/Keven/Documents/stanford local/cs224n project/224n-project/bi_lstm_encoder.py", line 43, in test_bilstm
out = session.run(pred, feed_dict={input_placeholder: doc, sequence_placeholder: sequence_length})
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/client/session.py", line 766, in run
run_metadata_ptr)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/client/session.py", line 964, in _run
feed_dict_string, options, run_metadata)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/client/session.py", line 1014, in _do_run
target_list, options, run_metadata)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/client/session.py", line 1034, in _do_call
raise type(e)(node_def, op, message)
tensorflow.python.framework.errors_impl.FailedPreconditionError: Attempting to use uninitialized value BiRNN/FW/LSTMCell/B
[[Node: BiRNN/FW/LSTMCell/B/read = Identity[T=DT_FLOAT, _device="/job:localhost/replica:0/task:0/cpu:0"](BiRNN/FW/LSTMCell/B)]]
Caused by op u'BiRNN/FW/LSTMCell/B/read', defined at:
File "/Applications/PyCharm CE.app/Contents/helpers/pydev/pydevd.py", line 1580, in <module>
globals = debugger.run(setup['file'], None, None, is_module)
File "/Applications/PyCharm CE.app/Contents/helpers/pydev/pydevd.py", line 964, in run
pydev_imports.execfile(file, globals, locals) # execute the script
File "/Users/Keven/Documents/stanford local/cs224n project/224n-project/bi_lstm_encoder.py", line 49, in <module>
test_bilstm()
File "/Users/Keven/Documents/stanford local/cs224n project/224n-project/bi_lstm_encoder.py", line 42, in test_bilstm
pred = BidirectionalLSTMEncoder().add_prediction_op(input_placeholder, sequence_placeholder, 6)
File "/Users/Keven/Documents/stanford local/cs224n project/224n-project/bi_lstm_encoder.py", line 20, in add_prediction_op
preds, _ = tf.nn.bidirectional_dynamic_rnn(cell_forward, cell_backward, inputs, sequence_length=sequence_length, dtype=tf.float32)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/rnn.py", line 652, in bidirectional_dynamic_rnn
time_major=time_major, scope=fw_scope)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/rnn.py", line 845, in dynamic_rnn
dtype=dtype)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/rnn.py", line 1012, in _dynamic_rnn_loop
swap_memory=swap_memory)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/control_flow_ops.py", line 2636, in while_loop
result = context.BuildLoop(cond, body, loop_vars, shape_invariants)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/control_flow_ops.py", line 2469, in BuildLoop
pred, body, original_loop_vars, loop_vars, shape_invariants)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/control_flow_ops.py", line 2419, in _BuildLoop
body_result = body(*packed_vars_for_body)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/rnn.py", line 995, in _time_step
skip_conditionals=True)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/rnn.py", line 403, in _rnn_step
new_output, new_state = call_cell()
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/rnn.py", line 983, in <lambda>
call_cell = lambda: cell(input_t, state)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/rnn_cell.py", line 500, in __call__
initializer=init_ops.zeros_initializer, dtype=dtype)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/variable_scope.py", line 1024, in get_variable
custom_getter=custom_getter)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/variable_scope.py", line 850, in get_variable
custom_getter=custom_getter)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/variable_scope.py", line 346, in get_variable
validate_shape=validate_shape)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/variable_scope.py", line 331, in _true_getter
caching_device=caching_device, validate_shape=validate_shape)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/variable_scope.py", line 677, in _get_single_variable
expected_shape=shape)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/variables.py", line 224, in __init__
expected_shape=expected_shape)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/variables.py", line 367, in _init_from_args
self._snapshot = array_ops.identity(self._variable, name="read")
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/ops/gen_array_ops.py", line 1424, in identity
result = _op_def_lib.apply_op("Identity", input=input, name=name)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/framework/op_def_library.py", line 759, in apply_op
op_def=op_def)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 2240, in create_op
original_op=self._default_original_op, op_def=op_def)
File "/usr/local/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 1128, in __init__
self._traceback = _extract_stack()
FailedPreconditionError (see above for traceback): Attempting to use uninitialized value BiRNN/FW/LSTMCell/B
[[Node: BiRNN/FW/LSTMCell/B/read = Identity[T=DT_FLOAT, _device="/job:localhost/replica:0/task:0/cpu:0"](BiRNN/FW/LSTMCell/B)]]
Code:
import tensorflow as tf
import numpy as np
from SubModel import SubModel
# input:
# shape=(?, max_timestep_doc2, 3 * word_vector_size)
#
# output:
# shape=(?, max_timestep_doc2, 2 * word_vector_size)
class BidirectionalLSTMEncoder(SubModel):
def add_prediction_op(self, inputs, output_size=None):
sequence_length = [5, 5]
cell_forward = tf.nn.rnn_cell.LSTMCell(output_size, num_proj=output_size)
cell_backward = tf.nn.rnn_cell.LSTMCell(output_size, num_proj=output_size)
preds, _ = tf.nn.bidirectional_dynamic_rnn(cell_forward, cell_backward, inputs, sequence_length=sequence_length, dtype=tf.float32)
return preds
def __init__(self):
pass
def test_bilstm():
print('testing bidirectional lstm layer')
with tf.variable_scope("test_bilstm_layer"):
input_placeholder = tf.placeholder(tf.float32, shape=(None, 5, 9))
sequence_placeholder = tf.placeholder(tf.int32, shape=(None,))
init = tf.global_variables_initializer()
with tf.Session() as session:
session.run(init)
doc = np.ones(shape=(2, 5, 9), dtype=np.float32) * 0.5
pred = BidirectionalLSTMEncoder().add_prediction_op(input_placeholder, 6)
out = session.run(pred, feed_dict={input_placeholder: doc})
print("out = " + str(out))
# assert np.allclose(CD_correct, out, atol=1e-2), "new state vector does not seem to be correct."
if __name__ == "__main__":
test_bilstm()

Answer 1

Never mind. It turns out I didn't initialize the variables properly..
I moved this line:
pred = BidirectionalLSTMEncoder().add_prediction_op(input_placeholder, 6)
above this line:
with tf.Session() as session:
Then everything worked fine. The functions containing variable initialization need to be called before tf.global_variables_initializer()