M-file S-function dimension

Can I define the S-function input/output dimension using another input parameters of my Simulink block?

For eg: there are 3 input and 1 output, first input is the row of third input, and second input is the column of the third input, then in the M-code setup function, i type:

block.InputPort(2).Dimensions = [block.InputPort(1).data block.InputPort(3).data];

Is this be possible? I need to do this as when my global parameters (1st and 2nd input) change in simulink, my 3rd input size will change. Hope someone can help. Thanks.

Answer 1

[Kaustubha Govind]

You shouldn't have to specify the input size of a variable-size signal - the S-function can get this information from the Simulink engine directly, as long as you can construct the input signals correctly and feed into port#2. In the setup() method, you can simply specify the input port dimensions mode as 'Variable':

   block.InputPort(2).DimensionsMode = 'Variable';

FYI, you can also look at the documentation example for Level-2 MATLAB S-Function with Variable-Size Signals. Type the following at the MATLAB prompt to open up the demo model:

   >> msfcndemo_varsize

[Chong Huan]

wow..You are indeed an expert =D I manage to solve the problem..Thanks Kaustubha =D

[Kaustubha Govind]

Glad to be of help! :)