import tensorflow as tf
 
def initialize_uninitialized(sess):
  global_vars     = tf.global_variables()
  is_not_initialized  = sess.run([tf.is_variable_initialized(var) for var in global_vars])
  not_initialized_vars = [v for (v, f) in zip(global_vars, is_not_initialized) if not f]
 
  print [str(i.name) for i in not_initialized_vars] # only for testing
  if len(not_initialized_vars):
    sess.run(tf.variables_initializer(not_initialized_vars))