%--------------------------
 % @Author: Jingqiao Hu
 % @Date: 2020-11-21 19:09:22
 % @LastEditTime: 2020-11-21 19:09:22
%--------------------------

% (2,2,m)*(2,2,m) => (4,m)*(4,m)
function z = matrix_3d_multiply(x, y)
    % 4*m
    z = [x(1,:).*y(1,:)+x(3,:).*y(2,:);
         x(2,:).*y(1,:)+x(4,:).*y(2,:); 
         x(1,:).*y(3,:)+x(3,:).*y(4,:); 
         x(2,:).*y(3,:)+x(4,:).*y(4,:)];
end