“ VQA项目” -Tensorflow错误-ValueError：不支持任何值。

Question

我正在做一个VQA项目，此代码来自github，链接为https://github.com/JamesChuanggg/VQA-tensorflow/blob/master/model_VQA.py

当我尝试使用以下代码训练模型时，

def train():
    print ('loading dataset...')
    dataset, img_feature, train_data = get_data()
    num_train = train_data['question'].shape[0]
    vocabulary_size = len(dataset['ix_to_word'].keys())
    print ('vocabulary_size : ' + str(vocabulary_size))

    print ('constructing  model...')
    model = Answer_Generator(
        rnn_size = rnn_size,
        rnn_layer = rnn_layer,
        batch_size = batch_size,
        input_embedding_size = input_embedding_size,
        dim_image = dim_image,
        dim_hidden = dim_hidden,
        max_words_q = max_words_q,  
        vocabulary_size = vocabulary_size,
        drop_out_rate = 0.5)

    tf_loss, tf_image, tf_question, tf_label = model.build_model()

    sess = tf.InteractiveSession(config=tf.ConfigProto(allow_soft_placement=True))
    saver = tf.train.Saver(max_to_keep=100)

    tvars = tf.trainable_variables()
    lr = tf.Variable(learning_rate)
    opt = tf.train.AdamOptimizer(learning_rate=lr)
    # gradient clipping
    gvs = opt.compute_gradients(tf_loss,tvars)

    clipped_gvs = [(tf.clip_by_value(grad, -10.0, 10.0),var) for grad, var in gvs]
    train_op = opt.apply_gradients(clipped_gvs)

    tf.initialize_all_variables()

    print ('start training...')
    for itr in range(max_itr):
        tStart = time.time()
        # shuffle the training data
        index = np.random.random_integers(0, num_train-1, batch_size)

        current_question = train_data['question'][index,:]
        current_length_q = train_data['length_q'][index]
        current_answers = train_data['answers'][index]
        current_img_list = train_data['img_list'][index]
        current_img = img_feature[current_img_list,:]

        # do the training process!!!
        _, loss = sess.run(
                [train_op, tf_loss],
                feed_dict={
                    tf_image: current_img,
                    tf_question: current_question,
                    tf_label: current_answers
                    })

        current_learning_rate = lr*decay_factor
        lr.assign(current_learning_rate).eval()

        tStop = time.time()
        if np.mod(itr, 100) == 0:
            print ("Iteration: ", itr, " Loss: ", loss, " Learning Rate: ", lr.eval())
            print ("Time Cost:", round(tStop - tStart,2), "s")
        if np.mod(itr, 15000) == 0:
            print ("Iteration ", itr, " is done. Saving the model ...")
            saver.save(sess, os.path.join(checkpoint_path, 'model'), global_step=itr)

    print ("Finally, saving the model ...")
    saver.save(sess, os.path.join(checkpoint_path, 'model'), global_step=n_epochs)
    tStop_total = time.time()
    print ("Total Time Cost:", round(tStop_total - tStart_total,2), "s")

但是我一直在得到这个结果和错误：

loading dataset...
loading json file...
loading image feature...
loading h5 file...
question aligning
Normalizing image feature
vocabulary_size : 12604
constructing  model...
Traceback (most recent call last):

  File "<ipython-input-185-4fb5017079bb>", line 3, in <module>
    train()

  File "<ipython-input-161-aee7f73e3494>", line 31, in train
    clipped_gvs = [(tf.clip_by_value(grad, -10.0, 10.0),var) for grad, var in gvs]

  File "<ipython-input-161-aee7f73e3494>", line 31, in <listcomp>
    clipped_gvs = [(tf.clip_by_value(grad, -10.0, 10.0),var) for grad, var in gvs]

  File "C:\Users\bk310\AppData\Local\conda\conda\envs\tf36\lib\site-packages\tensorflow\python\ops\clip_ops.py", line 59, in clip_by_value
    t = ops.convert_to_tensor(t, name="t")

  File "C:\Users\bk310\AppData\Local\conda\conda\envs\tf36\lib\site-packages\tensorflow\python\framework\ops.py", line 836, in convert_to_tensor
as_ref=False)

  File "C:\Users\bk310\AppData\Local\conda\conda\envs\tf36\lib\site-packages\tensorflow\python\framework\ops.py", line 926, in internal_convert_to_tensor
    ret = conversion_func(value, dtype=dtype, name=name, as_ref=as_ref)

   File "C:\Users\bk310\AppData\Local\conda\conda\envs\tf36\lib\site-packages\tensorflow\python\framework\constant_op.py", line 229, in _constant_tensor_conversion_function
    return constant(v, dtype=dtype, name=name)

  File "C:\Users\bk310\AppData\Local\conda\conda\envs\tf36\lib\site-packages\tensorflow\python\framework\constant_op.py", line 208, in constant
    value, dtype=dtype, shape=shape, verify_shape=verify_shape))

  File "C:\Users\bk310\AppData\Local\conda\conda\envs\tf36\lib\site-packages\tensorflow\python\framework\tensor_util.py", line 371, in make_tensor_proto
    raise ValueError("None values not supported.")

 ValueError: None values not supported.

任何人都可以告诉我什么原因导致此错误？？谢谢