keras-mxnet 无法从 pip 中正确拉出

Question

导入时出错 keras

>>> import keras
/Users/ray_zhang/anaconda3/envs/idp3/lib/python3.6/site-packages/daal/__init__.py:19: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
  import imp
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/ray_zhang/anaconda3/envs/idp3/lib/python3.6/site-packages/keras/__init__.py", line 3, in <module>
    from . import utils
  File "/Users/ray_zhang/anaconda3/envs/idp3/lib/python3.6/site-packages/keras/utils/__init__.py", line 6, in <module>
    from . import conv_utils
  File "/Users/ray_zhang/anaconda3/envs/idp3/lib/python3.6/site-packages/keras/utils/conv_utils.py", line 9, in <module>
    from .. import backend as K
  File "/Users/ray_zhang/anaconda3/envs/idp3/lib/python3.6/site-packages/keras/backend/__init__.py", line 98, in <module>
    raise ValueError('Invalid backend. Missing required entry : ' + e)
ValueError: Invalid backend. Missing required entry : placeholder

我正确安装了 mxnet：

>>> import mxnet as mx
/Users/ray_zhang/anaconda3/envs/idp3/lib/python3.6/site-packages/daal/__init__.py:19: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
  import imp
>>> a = mx.nd.ones((2,3))
>>> b = a*2+1
>>> b.asnumpy()
array([[3., 3., 3.],
       [3., 3., 3.]], dtype=float32)

我在 pip 中的 keras

(idp3) ? pip freeze | grep keras
keras-mxnet==2.2.0

~/.keras/keras.json

(idp3) ? cat ~/.keras/keras.json
{
    "floatx": "float32",
    "epsilon": 1e-07,
    "backend": "mxnet",
    "image_data_format": "channels_last"
}

看来我的 __init__.py在我的 keras 站点包中与当前的 github 版本不同：

我的 keras/backend/__init__.py

# Import backend functions.
if _BACKEND == 'cntk':
    sys.stderr.write('Using CNTK backend\n')
    from .cntk_backend import *
elif _BACKEND == 'theano':
    sys.stderr.write('Using Theano backend.\n')
    from .theano_backend import *
elif _BACKEND == 'tensorflow':
    sys.stderr.write('Using TensorFlow backend.\n')
    from .tensorflow_backend import *
else:
    # Try and load external backend.
    ...

但是在keras-mxnet 的 github 代表中：

# Import backend functions.
if _BACKEND == 'cntk':
    sys.stderr.write('Using CNTK backend\n')
    from .cntk_backend import *
elif _BACKEND == 'theano':
    sys.stderr.write('Using Theano backend.\n')
    from .theano_backend import *
elif _BACKEND == 'tensorflow':
    sys.stderr.write('Using TensorFlow backend.\n')
    from .tensorflow_backend import *
elif _BACKEND == 'mxnet':
    sys.stderr.write('Using MXNet backend\n')
    from .mxnet_backend import *
else:
    # Try and load external backend.
    ...

Answer 1

看起来您安装了 Keras 和 Keras-MXNet 的组合，这可以解释为什么您的init .py 不是最新的。

我建议对 keras 和 keras-mxnet 进行 pip 卸载，然后重新安装 keras-mxnet。

如果你真的需要在一台机器上安装两个版本，你可以将它们安装在不同的 conda 环境中。