how to make simulink matlab function work

i have matlab function m file like

function [out]  = cdmacodegenerator(in)
out=ones(in,in)
end

it is working fine but when i try to use it in simulink via matlab function block

it gives error

1. Data 'out' (#23) is inferred as a variable size matrix, while its specifiedtype is something else.
2. MATLAB Function Interface Error: Data 'out' (#23) is inferred as a variable size matrix, while its specified type is something else.
3. MATLAB Function Interface Error: Error in port widths or dimensions. Output port 1 of 'cdmacodegenerator/MATLAB Function1/in' is a one dimensional vector with 1 elements.

Answer 1

[Kaustubha Govind]

In this case, the output signal of the block has varying dimensions (ie. size changes during execution of the model). Such signals are called Variable-Size signals in Simulink. Since Simulink does not support dynamic-memory allocation, such signals need to specify an upper-bound for their size. You might want to limit your input signal to a reasonable upper bound and configure your output signal as Variable-size and configure the same upper bound on the MATLAB Function block's Ports and Data Manager.

[Juan Herrera]

Hi Kaustubha, I would like to be able to define the size via a calibration, therefore in the example from the question I set "in" as a parameter rather than an input and the variable "in" is defined in the workspace, however even in that case it returns the same error. To my understanding within the context of the simulation that parameter is fixed and so should be the size of the matrix. Is there a way to do this? Thanks in advance.