Keras 自定义生成器 TypeError：“NoneType”对象不可调用

Question

我编写了一个自定义生成器来加载我的数据集并将其提供给fit_generator 方法。但我遇到了一个错误。 question_train,img_lis_train 和 answers_train 是字符串列表。我希望mygen 返回格式为 32 个样本的批次：

[images,questions] , answers

代码如下：

def mygen(questions_train,img_lis_train,answers_train):
    start = 0  
    data_size = len(questions_train)
    batch_size = 32        
    while True:          
        if( start+batch_size <= data_size ):
            batch_ques = questions_train[ start : start+batch_size ] 
            batch_ans = answers_train[ start : start+batch_size ] 
            batch_img_names = img_lis_train[ start : start+batch_size ] 
        elif(start < data_size):
            batch_ques = questions_train[ start : ] 
            batch_ans = answers_train[ start : ] 
            batch_img_names = img_lis_train[ start : start+batch_size ] 
        else:
            start = 0
            continue       

        batch_img = []
        for img_name in batch_img_names:
            img = load_img('./dataset/images/' + str(img_name) + '.png' , target_size = (224,224))
            img = img_to_array(img)   
            batch_img.append( preprocess_input(img) )    

        start += 32
        print('start = ' + str(start))
        yield [batch_img, batch_ques] ,batch_ans

fc_model.fit_generator(mygen, steps_per_epoch=3376, epochs = 10)

这是我得到的错误：

  File "mycode.py", line 210, in <module>
    fc_model.fit_generator(mygen, steps_per_epoch=3376, epochs = 10)
  File "/opt/apps/Python-3.5.1/lib/python3.5/site-packages/keras/legacy/interfaces.py", line 87, in wrapper
    return func(*args, **kwargs)
  File "/opt/apps/Python-3.5.1/lib/python3.5/site-packages/keras/models.py", line 1223, in fit_generator
    initial_epoch=initial_epoch)
  File "/opt/apps/Python-3.5.1/lib/python3.5/site-packages/keras/legacy/interfaces.py", line 87, in wrapper
    return func(*args, **kwargs)
  File "/opt/apps/Python-3.5.1/lib/python3.5/site-packages/keras/engine/training.py", line 2083, in fit_generator
    generator_output = next(output_generator)
StopIteration
Exception ignored in: <bound method BaseSession.__del__ of <tensorflow.python.client.session.Session object at 0x7f936527fcc0>>
Traceback (most recent call last):
  File "/opt/apps/Python-3.5.1/lib/python3.5/site-packages/tensorflow/python/client/session.py", line 712, in __del__
  File "/opt/apps/Python-3.5.1/lib/python3.5/site-packages/tensorflow/python/framework/c_api_util.py", line 31, in __init__
TypeError: 'NoneType' object is not callable

Answer 1

您需要通过调用它并将数据传递给它来构造生成器，否则它应该如何生成批次？以下是正确的做法：

fc_model.fit_generator(mygen(q_train, i_train, a_train), ...)