I have installed Tensorflow and Keras by Anaconda (Conda Forge's packages) on Windows. This kind of installation has set Theano as primary backend, so I have checked the keras.json file, surprisingly it has set Tensorflow as the main backend. Furthermore, if I try to remove Theano's installation, Keras stop working. I am supposing that each time I run Keras, it override the json file.
How could I permanently set Tensorflow as primary backend?
In Windows, Try launching the Anaconda prompt from start -> Anaconda* -> Anaconda prompt
*Anaconda followed by your version, for me it is Anaconda3 (64-bit)
Check whether you can see the below as the first line
set "KERAS_BACKEND=theano"
In this case, by default you can go to the below directory (If you have set a custom install directory you might have to navigate there)
C:\Users\yourusername\AppData\Local\Continuum\Anaconda3\etc\conda\activate.d
and open the keras_activate batch file using notepad
Inside the file edit the line saying
set "KERAS_BACKEND=theano" to set "KERAS_BACKEND=tensorflow"
You are set to use Keras with tensorflow backend.