use mdarray::{view, tensor, DSlice, Expression};

fn matmul(a: &DSlice<f64, 2>, b: &DSlice<f64, 2>, c: &mut DSlice<f64, 2>) {
    for (mut cj, bj) in c.cols_mut().zip(b.cols()) {
        for (ak, bkj) in a.cols().zip(bj) {
            for (cij, aik) in cj.expr_mut().zip(ak) {
                *cij = aik.mul_add(*bkj, *cij);
            }
        }
    }
}

fn main() {
    let a = view![[1.0, 4.0], [2.0, 5.0], [3.0, 6.0]];
    let b = view![[0.0, 1.0], [1.0, 1.0]];

    let mut c = tensor![[0.0; 2]; 3];

    dbg!(std::any::type_name_of_val(&a));
    dbg!(std::any::type_name_of_val(&b));
    dbg!(std::any::type_name_of_val(&c));

    matmul(&a, &b, &mut c);

    assert_eq!(c, view![[4.0, 5.0], [5.0, 7.0], [6.0, 9.0]]);

    // slice
    let d = a.view(1, ..);
    dbg!(std::any::type_name_of_val(&d));

    // index
    let e = c[4];
    dbg!(std::any::type_name_of_val(&e));

    // permute
    let f = c.permute::<1, 0>();
    dbg!(std::any::type_name_of_val(&f));
}