Not found: Key Variable_<x> not found in checkpoint - python-3.x

Question

I am trying to save a trained model and use it later in another instance (function). But, somehow this throws me the variable not found error. After reagin through SO and other forums, I understand the problem is the way I store it.
dictionary, reverse_dictionary = build_dataset(training_data)
vocab_size = len(dictionary)
n_input = 3
n_hidden = 512
# RNN output node weights and biases
weights = {'out': tf.Variable(tf.random_normal([n_hidden, vocab_size]))}
biases = {'out': tf.Variable(tf.random_normal([vocab_size]))}
# tf Graph input
x = tf.placeholder("float", [None, n_input, 1])
y = tf.placeholder("float", [None, vocab_size])
# RNN implementation in Tensorflow
def RNN(x,weights,biases):
x = tf.reshape(x, [-1, n_input])
x = tf.split(x, n_input, 1)
rnn_cell = rnn.BasicLSTMCell(n_hidden)
outputs, states = rnn.static_rnn(rnn_cell, x, dtype=tf.float32)
return tf.matmul(outputs[-1], weights['out']) + biases['out']
pred = RNN(x, weights, biases)
learning_rate = 0.001
cost = tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits(logits=pred, labels=y))
optimizer = tf.train.RMSPropOptimizer(learning_rate=learning_rate).minimize(cost)
correct_pred = tf.equal(tf.argmax(pred,1), tf.argmax(y,1))
accuracy = tf.reduce_mean(tf.cast(correct_pred, tf.float32))
# Initializing the variables
init = tf.global_variables_initializer()
training_iters = 1000
display_step = 500
saver = tf.train.Saver()
# Launch the graph
with tf.Session() as session:
session.run(init)
step = 0
offset = random.randint(0, n_input+1)
end_offset = n_input + 1
acc_total = 0
loss_total = 0
while step < training_iters:
if offset > (len(training_data)-end_offset):
offset = random.randint(0, n_input+1)
symbols_in_keys = [ [dictionary[ str(training_data[i])]] for i in range(offset, offset+n_input) ]
symbols_in_keys = np.reshape(np.array(symbols_in_keys), [-1, n_input, 1])
symbols_out_onehot = np.zeros([vocab_size], dtype=float)
symbols_out_onehot[dictionary[str(training_data[offset+n_input])]] = 1.0
symbols_out_onehot = np.reshape(symbols_out_onehot, [1, -1])
_, acc, loss, onehot_pred = session.run([optimizer, accuracy, cost, pred], \
feed_dict={x: symbols_in_keys, y: symbols_out_onehot})
loss_total += loss
acc_total += acc
if (step+1) % display_step == 0:
print("Iter= " + str(step+1) + ", Average Loss= " + \
"{:.6f}".format(loss_total/display_step) + ", Average Accuracy= " + \
"{:.2f}%".format(100*acc_total/display_step))
acc_total = 0
loss_total = 0
symbols_in = [training_data[i] for i in range(offset, offset + n_input)]
symbols_out = training_data[offset + n_input]
symbols_out_pred = reverse_dictionary[int(tf.argmax(onehot_pred, 1).eval())]
print("%s - [%s] vs [%s]" % (symbols_in,symbols_out,symbols_out_pred))
step += 1
offset += (n_input+1)
saver.save(session, 'userLocation/Model')
While the model files are generated, but when I try to restore the model using
saver = tf.train.Saver()
with tf.Session() as restored_session:
saver.restore(restored_session, 'userLocation/Model')
Error
tensorflow.python.framework.errors_impl.NotFoundError: Key Variable_3 not found in checkpoint
[[Node: save_1/RestoreV2_7 = RestoreV2[dtypes=[DT_FLOAT], _device="/job:localhost/replica:0/task:0/cpu:0"](_recv_save_1/Const_0, save_1/RestoreV2_7/tensor_names, save_1/RestoreV2_7/shape_and_slices)]]
Any pointers as to what am i missing while saving.

Answer 1

I will explain this in 2 different part -
When you save the model in tensorflow, it will save graph in one file(usually the extention is .meta) and variable tensors in other file(usually index file).
Now, while importing you have to do the same 2 step process - a) import the graph first b) then create a session and import variables.
Here is a sample code -
import tensorflow as tf
import numpy as np
tf.set_random_seed(10)
#define graph location in variable
meta_file = 'userLocation/Model.meta'
#importing the graph
ns = tf.train.import_meta_graph(meta_file , clear_devices=True)
#create a session
with tf.Session().as_default() as sess:
#import variables
ns.restore(sess, meta_file[0:len(meta_file)-5])
# for example, if you have 'x' tenbsor in graph
x=tf.get_default_graph().get_tensor_by_name("x:0")
.
.
.
#Further processing/prediction etc