带回调的 Keras 评估生成器

Question

我有一个 keras 模型，我尝试使用测试数据和评估生成器方法对其进行测试。我有一个用例，该方法中的回调会派上用场。在 keras 文档中：evaluate_generator有一个回调参数。但是，当我使用以下代码对此进行测试时，出现错误。

model = load_model('/models/model.h5')

img_width = 120
img_height = 120
batch_size = 32

data_generator = ImageDataGenerator(rescale=1. / 255.)

test_generator = data_generator.flow_from_directory(
        '/data/test',
        target_size=(img_width, img_height),
        batch_size=batch_size,
        class_mode='binary')

STEP_SIZE_TEST = test_generator.n // test_generator.batch_size


class TestCallback(Callback):
    def on_test_batch_begin(self, batch, logs=None):
        print('Evaluating batch: ' + str(batch))


test_callback = TestCallback()

model.evaluate_generator(test_generator, STEP_SIZE_TEST, callbacks=[test_callback])

错误：

Traceback (most recent call last):
  File "/test_callback.py", line 34, in <module>
    model.evaluate_generator(generator=test_generator, steps=STEP_SIZE_TEST, callbacks=[test_callback])
  File "/miniconda3/envs/models/lib/python3.6/site-packages/keras/legacy/interfaces.py", line 91, in wrapper
    return func(*args, **kwargs)
TypeError: evaluate_generator() got an unexpected keyword argument 'callbacks'

当我编辑代码并像这样省略关键字时：

model.evaluate_generator(test_generator, STEP_SIZE_TEST, [test_callback])

我收到以下错误：

Exception in thread Thread-16:
Traceback (most recent call last):
  File "/miniconda3/envs/models/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "/miniconda3/envs/models/lib/python3.6/threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "/miniconda3/envs/models/lib/python3.6/site-packages/keras/utils/data_utils.py", line 671, in _run
    executor.apply_async(next_sample, (self.uid,)), block=True)
  File "/miniconda3/envs/models/lib/python3.6/queue.py", line 127, in put
    if self.maxsize > 0:
TypeError: '>' not supported between instances of 'list' and 'int'

我的 keras 版本是 2.2.4

Answer 1

您看到的文档适用于 master 分支。2.2.4 不支持 'callbacks' 参数。在 2.2.4 中，第三个参数仍然是 max_queue_size，因此将 [test_callback] 列表解释为 int 时会出现错误。