1.关于tf.train.MonitoredTrainingSession

with tf.train.MonitoredTrainingSession(
            master=master,
            is_chief=is_chief,
            checkpoint_dir=ckpt_dir,
            save_checkpoint_secs=None,
            log_step_count_steps=None,
            config=config) as sess:

checkpoint_dir参数表示执行sess.run之前，模型首先会按照checkpoint_dir的路径去加载训练好的参数