在{'theano'，'tensorflow'}断言_backend断言

Question

I'm trying to run this code , but getting the following error:

Traceback (most recent call last):
  File "classifier_from_little_data_script_3.py", line 39, in <module>
    from keras import applications
  File "C:\Python35\lib\site-packages\keras\__init__.py", line 3, in <module>
    from . import activations
  File "C:\Python35\lib\site-packages\keras\activations.py", line 3, in <module>
    from . import backend as K
  File "C:\Python35\lib\site-packages\keras\backend\__init__.py", line 36, in <module>
    assert _backend in {'theano', 'tensorflow'}
AssertionError

I tried looking for a reason for this error, but couldn't find a solution. How can I fix this issue?

EDIT 1

This is the keras.json file:

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

EDIT 2

I have changed the backend to tensorflow , but get the following error:

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.

I have added a separate question for the second edit, here .

Thanks.

Answer 1

your keras.json should look like this

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

Notice the difference "backend" : "tensorflow" versus what you have "backend" : "tf"