function [sys,x0,str,ts] = my_qr(t,x,u,flag)

switch flag,
  
  case 0
    [sys,x0,str,ts]=mdlInitializeSizes;

  case 3
    sys=mdlOutputs(t,x,u);

  case { 1, 2, 4, 9 }
    sys=[];

  otherwise
    error(['Unhandled flag = ',num2str(flag)]);

end

function [sys,x0,str,ts] = mdlInitializeSizes()

sizes = simsizes;
sizes.NumContStates  = 0;
sizes.NumDiscStates  = 0;
sizes.NumOutputs     = 64;   % dynamically sized
sizes.NumInputs      = 32;  % dynamically sized
sizes.DirFeedthrough = 1;   % has direct feedthrough
sizes.NumSampleTimes = 1;

sys = simsizes(sizes);
str = [];
x0  = [];
ts  = [-1 0];   % inherited sample time

% end mdlInitializeSizes

function sys = mdlOutputs(t,x,u)
H_re = reshape(u(1:16),4,4);
H_im = reshape(u(17:32),4,4);
H = H_re + H_im*j;
[Q R] = qr(H);
Q_re = real(Q);
Q_im = imag(Q);
R_re = real(R);
R_im = imag(R);
sys = [reshape(Q_re,16,1);reshape(Q_im,16,1);reshape(R_re,16,1);reshape(R_im,16,1)];

% end mdlOutputs