Dynamically Sized Inputs and Outputs

Hello,

I understand that when building an S-Function, whether from an M-File, C-MEX or S-Function Builder, with dynamically sized inputs and outputs Simulink always set the outputs width as the same size of the inputs.

Is there any way of bypassing this restriction?

I would like to create an S-Function in which both inputs and outputs are dynamically sized, although the size of the output must be defined from a fixed-size input.

Thank you.

[Kaustubha Govind]

Daniel: Do you mean the output is a variable-size signal whose size varies depending on the value of the input?

[Daniel]

Yes, I would need an S-Function with two inputs (one being a vector and the other a single element). The second input will determine the size of the output and it is not the same size of the vector input.

Thank you

Answer 1

[Guy Rouleau]

Give a look at this post about creating variable size signals and s-function:

http://blogs.mathworks.com/seth/2011/06/28/variable-size-signals-and-unit-delay/

You will see that you have 2 options to determine the dimension of the output. If you type sfundemos in MATLAB, you will see ll example of s-function. Dig through that and you will find examples for both.