Simulink, How does this m-code block work while having input mismatch?

Question

In MATLAB Simulink, I added an MPC (Model predictive control block).

I looked inside this block:

Inside it there is a wrapper subsystem called MPC. I opened this one via double click:

The main block inside this subsystem is optimizer. This block is a m-code block starting with this header:

function [xk1, u, cost, useq, status, xest, iAout] = fcn(...
            xk, old_u, ym, ref, md, umin, umax, ymin, ymax, switch_in, ext_mv, MVtarget, isQP, nx, nu, ny, degrees, Hinv, Kx, Ku1, Kut, Kr, Kv, Mlim, ...
            Mx, Mu1, Mv, z_degrees, utarget, p, uoff, voff, yoff, maxiter, nxQP, openloopflag, ...
            lims_inport, no_umin, no_umax, no_ymin, no_ymax, switch_inport, no_switch, enable_value, ...
            return_cost, H, return_sequence, Linv, Ac, ...
            ywt, uwt, duwt, rhoeps, iA, ...
            no_ywt, no_uwt, no_duwt, no_rhoeps,...
            Wy, Wdu, Jm, SuJm, Su1, Sx, Hv, Wu, I1, ...
            A, Bu, Bv, C, Dv, Mrows, nCC, Ecc, Fcc, Scc, Gcc, ...
            nv, no_md, no_ref, no_uref, no_mv, Rscale, MDscale, myindex, ...
            myoff, xoff, CustomEstimation, M, L)
%#codegen
coder.extrinsic('mpcblock_optimizer_double_mex');
coder.extrinsic('mpcblock_optimizer_single_mex');
coder.extrinsic('mpcblock_refmd_double_mex');
coder.extrinsic('mpcblock_refmd_single_mex');

My question is that why the number of inputs of the function in the code is much higher than the number of inputs ports of this block in simulink. Where are these variables generated? For example how is argument H created before this function is called?

Here the Simulink file is attached:

https://www.dropbox.com/s/vx67urpkt9qki9e/simulink.zip?dl=0

Interesting question! Tried to figure out about this, but can't open your model in due to you have newer MATLAB version. — Mikhail_Sam, Mar 11 '16 at 08:45
@Mikhail_Sam in your matlab please add an MPC block and try to open it. — ar2015, Mar 11 '16 at 23:53

score 2 · Answer 1 · answered Mar 11 '16 at 10:20

2

I suspect some of the "inputs" are not actually inputs, but parameters passed to the function. See Add Parameter Arguments in the documentation for more details.

answered Mar 11 '16 at 10:20

am304

13,758
2
22
40

Thanks a lot. Is there any way to trace where parameter `H` comes from? http://i.stack.imgur.com/WIuLT.png – ar2015 Mar 12 '16 at 03:20
Have a look at the mask of the block, I suspect it is defined in here somewhere. @Daniel's suggestion of looking at the workspace variables in the model explorer is also a good one. – am304 Mar 13 '16 at 16:20

score 2 · Answer 2 · answered Mar 11 '16 at 10:20

2

For a Matlab Function block, there are two types of input arguments to the m-code. The input signals you already know and parameters. Go to edit data, you will see which are switched to paremeter, these variables come from a mask or your workspace.

answered Mar 11 '16 at 10:20

Daniel

36,610
3
36
69

Thanks a lot. Is there any way to trace where parameter `H` comes from? http://i.stack.imgur.com/WIuLT.png – ar2015 Mar 12 '16 at 03:19
http://www.mathworks.com/help/simulink/ug/workspace-variables-in-model-explorer.html – Daniel Mar 12 '16 at 10:03

Simulink, How does this m-code block work while having input mismatch?

2 Answers2