How to change Keras backend (where's the json file)?

The official Keras Documentation may help you. This link shows how to change the backend of Keras. You have to change the ~/.keras/keras.json from ‘backend’: ‘tensorflow’, to ‘backend’: ‘theano’.

In case of Ubuntu,the following worked for me:

The ‘.keras’ folder is present in your home directory,but is hidden.So,you need to unhide the hidden files in your home directory.
You can see the hidden files in Ubuntu by

• View-> show hidden files or
• pressing ctrl+H.

You can now see the ‘.keras’ folder in your home directory.Inside that folder,you will see the ‘keras.json’ file which you can modify to switch the keras backend to theano according to the official documentation https://keras.io/backend/

“Can’t find your keras.json file? : Windows
On most systems the keras.json file (and associated sub-directories) will not be created until you open up a Python shell and directly import the keras package itself.

If you find that the ~/.keras/keras.json file does not exist on your system, simply open up a shell, (optionally) access your Python virtual environment (if you are using virtual environments), and then import Keras:

$ workon keras_tf
$ python
>>> import keras
>>> quit()

“

Referenced from : keras-with-tensorflow/theano-backend

For those with a python shell open:

import os

with open(os.path.expanduser('~')+'\.keras\keras.json','w') as f:
    new_settings = """{rn
    "epsilon": 1e-07,rn
    "image_data_format": "channels_last",n
    "backend": "theano",rn
    "floatx": "float32"rn
    }"""
    f.write(new_settings)

import keras

In case you want to change the config, the json is available here: ~/.keras/keras.json

To do this dynamically in python 2.7 you can run:

from keras import backend as K
import os

def set_keras_backend(backend):

    if K.backend() != backend:
        os.environ['KERAS_BACKEND'] = backend
        reload(K)
        assert K.backend() == backend

set_keras_backend("theano")

Just to add this informative post. I’m using anaconda for my task. And imported keras through my anaconda python. So keras got installed in

C:UsersusernameAppDataLocalContinuumAnaconda3Libsite-packages

There are 2 folders in site-packages: keras & Keras-1.0.8.dist-info.

In Keras-1.0.8.dist-info, there’s a file called metadata.json. This by default has “Theano” as backend. So, if you change that to tensorflow, you will get tensoflow backend.

Hope it will help someone who has might type of issues.

Type following and press enter on command prompt:

%USERPROFILE%/.keras/keras.json

Change backend in the opened text file and save it.

For Linux systems, the hidden .keras directory will be created in the user’s home directory. To observe whether or not it has been created, run the following command from your home directory (the -a allows you to see hidden files and directories).

    ls –a 

If the directory is there, then cd into it and modify the keras.json file. If it’s not there, then create the directory with

    mkdir .keras

Then create the file with

    touch keras.json 

Then edit the file to make the config changes you referenced to change the backend engine to Theano.

This process is covered fully in this video.

In ubuntu you can use this command to open keras.json file in vi editor and editing and saveing

sudo vi $HOME/.keras/keras.json

or use the following for opening in gedit

sudo gedit $HOME/.keras/keras.json

You can directly use,

import os
os.environ['KERAS_BACKEND']='theano'

or

os.environ['KERAS_BACKEND']='tensorflow'

Simplest Solution:

Google’s TensorFlow is default backend for keras but for example if u want to change it with theano then
First check if the alternate backend you wish to work with is installed successfully by importing it in python shell:

import theano as th

if that works fine

Step 2: if you have installed keras, theano in virtualenv then go to virtualenv directory

e.g virtualenv/virtual/lib/python2.7/site-packages/keras/backend/

open init.py
change line 27

Default backend: TensorFlow.
_BACKEND = 'theano'

and thats it

open python shell
and import keras

import keras as kd