Function artha::matrix::sigmoid_prime

pub fn sigmoid_prime<T>(current: &Matrix<T>) -> Matrix<f64> where
    f64: From<T>,
    T: Copy, 

Loops through the Matrix and calculates sigmoid prime of each value.

Note: Since taking the sigmoid of each value in the matrix requires it to be converted to floating point and From f64 trait is not implemented for i32/64 nor for u32/64/size, this function returns f64 Matrix