FailedPreconditionError: FailedPr...onError() - tensorflow

Question

I have FailedPreconditionError when running sess.
My network has two different parts, pretrained-network and new add in Recognition network.
Pretrained model is used to extract features and the feature is used to train again for recognition.
In my code, pre-trained model is loaded first.
graph = tf.Graph()
with graph.as_default():
input_data, input_labels, input_boxes = input_train_data.input_fn()
input_boxes = tf.reshape(input_boxes,[input_boxes.shape[0]*2,-1])#convert from Nx8 to 2Nx4
# build model and loss
net = Net(input_data, is_training = False)
f_saver = tf.train.Saver(max_to_keep=1000, write_version=tf.train.SaverDef.V2, save_relative_paths=True)
sess_config = tf.ConfigProto(log_device_placement = False, allow_soft_placement = True)
if FLAGS.gpu_memory_fraction < 0:
sess_config.gpu_options.allow_growth = True
elif FLAGS.gpu_memory_fraction > 0:
sess_config.gpu_options.per_process_gpu_memory_fraction = FLAGS.gpu_memory_fraction;
session = tf.Session(graph=graph, config=sess_config)
tf.logging.info('Initialize from: ' + config.train.init_checkpoint)
f_saver.restore(session, config.train.init_checkpoint)
f_saver restores the pre-trained model.
Then feature conv5_3 is extracted and fed into Recognition network.
conv5_3 = net.end_points['conv5_3']
with tf.variable_scope("Recognition"):
global_step_rec = tf.Variable(0, name='global_step_rec', trainable=False)
#Pass through recognition net
r_net = regnet.ConstructRecNet(conv5_3)
conv7_7 = r_net.end_points['pool7']
#implement ROI Pooling
#input boxes be in x1, y1, x2, y2
h_fmap = tf.dtypes.cast(tf.shape(conv7_7)[1],tf.float32)
w_fmap = tf.dtypes.cast(tf.shape(conv7_7)[2],tf.float32)
#remap boxes at input images to feature mats
#input_boxes = input_boxes / tf.constant([config.train.input_shape[0], config.train.input_shape[0],\
# config.train.input_shape[0], config.train.input_shape[0]], dtype=tf.float32)#Normalize with image size first
remap_boxes=tf.matmul(input_boxes,tf.diag([w_fmap,h_fmap,w_fmap,h_fmap]))
#put first column with image indexes
rows = tf.expand_dims(tf.range(remap_boxes.shape[0]), 1)/2
add_index = tf.concat([tf.cast(rows,tf.float32),remap_boxes],-1)
index = tf.not_equal(tf.reduce_sum(add_index[:,4:],axis=1),0)
remap_boxes = tf.gather_nd(add_index,tf.where(index))
remap_boxes=tf.dtypes.cast(remap_boxes,tf.int32)
prob = roi_pooling(conv7_7, remap_boxes, pool_height=1, pool_width=28)
#Get features for CTC training
prob = tf.transpose(prob, (1, 0, 2)) # prepare for CTC
data_length = tf.fill([tf.shape(prob)[1]], tf.shape(prob)[0]) # input seq length, batch size
ctc = tf.py_func(CTCUtils.compute_ctc_from_labels, [input_labels], [tf.int64, tf.int64, tf.int64])
ctc_labels = tf.to_int32(tf.SparseTensor(ctc[0], ctc[1], ctc[2]))
predictions = tf.to_int32(tf.nn.ctc_beam_search_decoder(prob, data_length, merge_repeated=False, beam_width=10)[0][0])
tf.sparse_tensor_to_dense(predictions, default_value=-1, name='d_predictions')
tf.reduce_mean(tf.edit_distance(predictions, ctc_labels, normalize=False), name='error_rate')
loss = tf.reduce_mean(tf.compat.v1.nn.ctc_loss(inputs=prob, labels=ctc_labels, sequence_length=data_length, ctc_merge_repeated=True), name='loss')
learning_rate = tf.train.piecewise_constant(global_step_rec, [150000, 200000],[config.train.learning_rate, 0.1 * config.train.learning_rate,0.01 * config.train.learning_rate])
opt_loss = tf.contrib.layers.optimize_loss(loss, global_step_rec, learning_rate, config.train.opt_type,config.train.grad_noise_scale, name='train_step')
tf.global_variables_initializer()
I can run sess till feature extraction conv5_3. But can't run those in Recognition and got error as FailedPreconditionError: FailedPr...onError(). What could be the problem?
graph.finalize()
with tf.variable_scope("Recognition"):
for i in range(config.train.steps):
input_data_, input_labels_, input_boxes_ = session.run([input_data, input_labels, input_boxes])
conv5_3_ = session.run([conv5_3]) #can run this line
global_step_rec_ = session.run([global_step_rec]) # got FailedPreconditionError: FailedPr...onError() error at this line
conv7_7_ = session.run([conv7_7])
h_fmap_ = session.run([h_fmap])

Answer 1

Now it works.
Since my graph has two parts, I need to initialize separately.
(1)First get all variables from pre-trained model to initialize with those from checkpoint.
Then initialize with tf.train.Saver.
(2)Then initialize the rest add-in layers using tf.global_variables_initializer()
My code is as follow.
#Initialization
#Initialize pre-trained model first
#Since we need to restore pre-trained model and initialize to respective variables in this current graph
#(1)make a variable list for checkpoint
#(2)initialize a saver for the variable list
#(3)then restore
#(1)
def print_tensors_in_checkpoint_file(file_name, tensor_name, all_tensors):
varlist=[]
reader = pywrap_tensorflow.NewCheckpointReader(file_name)
if all_tensors:
var_to_shape_map = reader.get_variable_to_shape_map()
for key in sorted(var_to_shape_map):
print(key)
varlist.append(key)
return varlist
varlist=print_tensors_in_checkpoint_file(file_name=config.train.init_checkpoint,all_tensors=True,tensor_name=None)
#(2)prepare the list of variables by calling variables = tf.get_collection(tf.GraphKeys.GLOBAL_VARIABLES)
variables = tf.get_collection(tf.GraphKeys.GLOBAL_VARIABLES)
#countcheckpt_vars=0
#for n in tf.get_default_graph().as_graph_def().node:
# print(n.name)
#for op in tf.get_default_graph().get_operations():
# print(str(op.name))
#for var in zip(variables):
# countcheckpt_vars=countcheckpt_vars+1
#(3)
loader = tf.train.Saver(variables[:46])#since I need to initialize only 46 variables from global variables
tf.logging.info('Initialize from: ' + config.train.init_checkpoint)
sess_config = tf.ConfigProto(log_device_placement = False, allow_soft_placement = True)
if FLAGS.gpu_memory_fraction < 0:
sess_config.gpu_options.allow_growth = True
elif FLAGS.gpu_memory_fraction > 0:
sess_config.gpu_options.per_process_gpu_memory_fraction = FLAGS.gpu_memory_fraction;
session = tf.Session(graph=graph, config=sess_config)
loader.restore(session, config.train.init_checkpoint)
Then initialize the rest of variables
init = tf.global_variables_initializer()
session.run(init)