S-function input ports with different variable dimensions

Hi all,

I am writing a C S-function for Simulink, with two input ports. The width of both ports is set to DYNAMICALLY_SIZED, because the input is a one dimensional vector with 1 or 4 elements. Everything goes well as long as both input signals have the same dimension (1 or 4). However, when the input signals have different dimensions (1 for the first and 4 for the second, or vice versa) the S-function doesn't run. There is an error which says that the input port is vector with 1 element, allthough the signal that goes to the input port is a vector with 4 elements.

Does anyone have an idea on what I am doing wrong, or what might be the solution to this problem?

Answer 1

[Kaustubha Govind]

The documentation suggests that you implement mdlSetInputPortDimensionInfo. Please try adding these lines to your S-function:

#define MDL_SET_INPUT_PORT_DIMENSION_INFO
#if defined(MDL_SET_INPUT_PORT_DIMENSION_INFO) && defined(MATLAB_MEX_FILE)
void mdlSetInputPortDimensionInfo(SimStruct *S, int_T port,
  const DimsInfo_T *dimsInfo)
{
    if (!ssSetInputPortDimensionInfo(S, port, dimsInfo)) return;
}
#endif