Function sgemm_nn 

pub fn sgemm_nn(
    m: usize,
    n: usize,
    k: usize,
    a: &[f32],
    b: &[f32],
    c: &mut [f32],
)

Safe wrapper computing C = A * B for row-major matrices with no transpose.

a is m x k, b is k x n, c is m x n. Uses alpha = 1, beta = 0 (C is overwritten).