Matrix.opBinary

alias Mat23 = Matrix!(int, 2, 3);
alias Mat12 = Matrix!(int, 1, 2);

Mat23 m1 = Mat23.fromRows(1, 1,
                          2, 2,
                          3, 3);
Mat12 m2 = Mat12.fromRows(4,
                          5);
auto result = m1 * m2;
assert(result.elements == [
    1*4 + 1*5,
    2*4 + 2*5,
    3*4 + 3*5,
]);