assert _backend in {'theano'， 'tensorflow'} AssertionError

Question

我正在尝试运行此代码，但收到以下错误：

Traceback (most recent call last):
  File "classifier_from_little_data_script_3.py", line 39, in <module>
    from keras import applications
  File "C:Python35libsite-packageskeras__init__.py", line 3, in <module>
    from . import activations
  File "C:Python35libsite-packageskerasactivations.py", line 3, in <module>
    from . import backend as K
  File "C:Python35libsite-packageskerasbackend__init__.py", line 36, in <module>
    assert _backend in {'theano', 'tensorflow'}
AssertionError

我试图寻找此错误的原因，但找不到解决方案。如何解决此问题？

编辑 1

这是keras.json文件：

{
    "image_dim_ordering": "tf",
    "epsilon": 1e-07,
    "floatx": "float32",
    "backend": "tf"
}

编辑 2

我已将后端更改为tensorflow，但出现以下错误：

ValueError: The shape of the input to "Flatten" is not fully defined (got (None, None, 512). Make sure to pass a complete "input_shape" or "batch_input_shape" argument to the first layer in your model.

我在这里为第二次编辑添加了一个单独的问题。

谢谢。

Answer 1

你的keras.json应该看起来像这样

{
    "image_data_format": "channels_last",
    "epsilon": 1e-07,
    "floatx": "float32",
    "backend": "tensorflow" 
}

请注意"backend" : "tensorflow"与现有"backend" : "tf"的差异