def evaluate():
    """Eval CIFAR-10 for a number of steps."""
    with tf.Graph().as_default():
        # Get images and labels for CIFAR-10.
        eval_data = FLAGS.eval_data == 'test'
        images, labels = cifar10.inputs(eval_data=eval_data)

        # Build a Graph that computes the logits predictions from the
        # inference model.
        logits = cifar10.inference(images)

        # Calculate predictions.
        top_k_op = tf.nn.in_top_k(logits, labels, 1)

        # Restore the moving average version of the learned variables for eval.
        variable_averages = tf.train.ExponentialMovingAverage(
            cifar10.MOVING_AVERAGE_DECAY)
        variables_to_restore = variable_averages.variables_to_restore()
        saver = tf.train.Saver(variables_to_restore)

        # Build the summary operation based on the TF collection of Summaries.
        summary_op = tf.merge_all_summaries()

        graph_def = tf.get_default_graph().as_graph_def()
        summary_writer = tf.train.SummaryWriter(FLAGS.eval_dir,
                                                graph_def=graph_def)

        while True:
            eval_once(saver, summary_writer, top_k_op, summary_op)
            if FLAGS.run_once:
                break
            time.sleep(FLAGS.eval_interval_secs)
def train():
    '''
    训练 CIFAR-10
    '''
    with tf.Graph().as_default():
        global_step = tf.Variable(0, trainable=False)


        # Get images and labels for CIFAR-10
        images, labels = cifar10.distorted_inputs()

        # 构建inference图
        logits = cifar10.inference(images)

        loss = cifar10.loss(logits, labels)

        # 构建训练图
        train_op = cifar10.train(loss, global_step)

        # saver
        saver = tf.train.Saver(tf.all_variables())

        # 构建总结操作
        summary_op = tf.merge_all_summaries()

        # 初始化操作
        init = tf.initialize_all_variables()

        sess = tf.Session(config=tf.ConfigProto(log_device_placement=FLAGS.log_device_placement))

        sess.run(init)

        tf.train.start_queue_runners(sess=sess)

        summary_writer = tf.train.SummaryWriter(FLAGS.train_dir, graph_def=sess.graph_def)

        for step in range(FLAGS.max_steps):
            start_time = time.time()
            _, loss_value = sess.run([train_op, loss])
            duration = time.time() - start_time

            # 模型收敛
            assert not np.isnan(loss_value), "Model diverged with loss = NAN"

            if step % 10 == 0:
                num_examples_per_step = FLAGS.batch_size
                examples_per_sec = num_examples_per_step / duration
                sec_per_batch = float(duration)
                format_str = ('%s: step %d, loss = %.2f (%.1f examples/sec; %.3f '
                              'sec/batch)')
                print(format_str % (datetime.now(), step, loss_value,
                                    examples_per_sec, sec_per_batch))

            if step % 100 == 0:
                summary_str = sess.run(summary_op)
                summary_writer.add_summary(summary_str, step)

            if step % 1000 == 0 or (step + 1) == FLAGS.max_steps:
                checkpoint_path = os.path.join(FLAGS.train_dir, "model.ckpt")
                saver.save(sess, checkpoint_path, global_step=step)