inherit dimension of multiple input port in a Level-2 S-Function

I'm using a QP solver (qpas.mex) in Simulink that requires a Level-2 S-Function block. However, I have trouble to specify the dimension of each input port. Here is the setup

function mySFcn(block)
  setup(block);

function setup(block)
  nInPorts = 2;
  block.NumInputPorts  = nInPorts;
  block.NumOutputPorts = 1;

    for i = 1 : nInPorts
      block.InputPort(i).Dimensions  = -1;
      block.InputPort(i).DatatypeID  = 0;  % double
      block.InputPort(i).Complexity  = 'Inherited';
      block.InputPort(i).DirectFeedthrough = true;
      block.InputPort(i).SamplingMode = 'Inherited';
    end

    block.OutputPort(1).Dimensions  = -1;
    block.OutputPort(1).DatatypeID  = 0; % double
    block.OutputPort(1).Complexity  = 'Inherited';

    block.NumDialogPrms     = 0;
    block.SampleTimes = [-1 0];
    block.SimStateCompliance = 'DefaultSimState';

    block.RegBlockMethod('Outputs', @Outputs);     % Required
    block.RegBlockMethod('Terminate', @Terminate); % Required

function Outputs(block)
  W = block.InputPort(1).Data;      % 12 x 12, e.g.
  tau = block.InputPort(2).Data;    % 3 x 1, e.g.
  block.OutputPort(1).Data = qpas(W,tau);   % e.g.

function Terminate(block)

I always get an error message that states a 12x12 matrix cannot get into my s-function block through port 1. Anybody know how to correct this error? By the way, each port will have different dimension, and I have no way to know the dimension.

[Mike Quan]

Hello Mr Quan,

I have a similiar problem, where the dimension of the biggest input matrix somehow determines the dimensions for any other inut AND output.

Also I tried making input/output sizing inherited by

    block.SetPreCompInpPortInfoToDynamic;
    block.SetPreCompOutPortInfoToDynamic;

without success! Please tell, if you find a solution!

Answer 1

[Ridouane OULHIQ]

Just don't set the dimension