Function gradient 

pub fn gradient<T>(input: &Array<T>) -> (Array<T>, Array<T>)
where
    T: HasAfEnum + FloatingPoint,

Calculate the gradients

The gradients along the first and second dimensions are calculated simultaneously.

Parameters

• input is the input Array

Return Values

A tuple of Arrays.

The first Array is dx which is the gradient along the 1st dimension.

The second Array is dy which is the gradient along the 2nd dimension.