What's the purpose of keras.backend.function()

Question

The Keras manual doesn\'t say too much:

keras.backend.function(inputs, outputs, updates=None)

Instantiates a Keras function.
Arguments
inputs: List of place         


        

Answer 1

Think it as a function wrapper. In framework of keras and tensorflow, it wrappers list of tensor as input and does some operations on weights in network (backward propagation). It is specially useful in field of Reinforcement learning, where the loss is computed after actions(model output) and model.fit is too macro to incorporate such op.