Function ew_op 

pub fn ew_op<'a, T, F, D, S, Host>(
    device: &'a Host,
    lhs: &Matrix<'_, T, D, S>,
    rhs: &Matrix<'_, T, D, S>,
    f: F,
) -> Matrix<'a, T, Host, S>
where
    T: Copy + Default,
    F: Fn(T, T) -> T,
    D: MainMemory,
    S: Shape,
    Host: for<'b> Alloc<'b, T, S> + MainMemory,