from https://github.com/rayheberer/SC2Agents/blob/master/deepq_agents.py

update_target_network.py

 class DQNMoveOnly(base_agent.BaseAgent):
     # ...
     # ...
     # ...
     # ...
     def _update_target_network(self):
        online_vars = tf.get_collection(
            tf.GraphKeys.TRAINABLE_VARIABLES, 'DQN')
        target_vars = tf.get_collection(
            tf.GraphKeys.TRAINABLE_VARIABLES, 'DQNTarget')

        update_op = []
        for online_var, target_var in zip(online_vars, target_vars):
            update_op.append(target_var.assign(online_var))

        self.sess.run(update_op)
    # ...
    # ... 
    # ...
    #