Problem with variable size output/input signals in Embedded Function Blocks in Simulink

Hello Everyone ,

Problem Situation : I have a M Function which i need to use in Simulink . lets say that I need to use following function.

function [a,b] = foo(p,q,r)
%#codegen
% Some operation

end

So , Regarding this Function, Some of the inputs are constants, some of them are varying size input/outputs for different time steps. When I was trying to run the model ,it did throw me a warning saying about the varying sizes of inputs/outputs. Then I went to model explorer, and did navigate to the Corresponding function , and checked the "variable size" box for variable inputs/outputs and left the size as -1... For those as constants , I gave the size as [1 1] and leaving the "variable Size" unchecked.

but still I get an error Like

Output 'OutputLaneData' has variable size but the upper bound is not specified; explicit upper bound must be provided.

Do i need to explictly mention the maximum limits of all outputs in the function like this

function [a,b] = foo(p,q,r)
%#codegen
coder.varsize('a',[1 10000]);  % The Maximum size of a can be [1 x 10000]
coder.varsize('b',[1 99999]);  % The Maximum size of a can be [1 x 99999]
% Some operation
end

Even though I did something like to this to my functions, it still complains me . I even did add maximum and minimum values in the model explorer... Do i still need to do something more ?? Am i missing anything ...

please comment to know about it... Any questions are welcome.

[Vandana Rajan]

Hi, What are the operations that you are trying to do with these variable-size inputs? Are you trying to perform some concatenation with the variable size arrays?

[Ash1992]

Hello Vandana .... The operations include some searching,filtering and Yes,I am performing some concatenation of those outputs with some constants if a conditions satisfies.

[Sudarshan Kolar]

You might find these docs helpful to resolve the issue:

1. https://www.mathworks.com/help/coder/ug/code-generation-for-variable-size-data.html (see generating code for MATLAB Functions with Variable-Size Data and the section after it)

2. https://www.mathworks.com/help/coder/ug/troubleshooting-issues-with-variable-size-data.html#br9sjhb

3. https://www.mathworks.com/help/coder/ug/variable-size-data-when-dynamic-memory-allocation-is-disabled.html#br9t1u3

The doc is suggesting to use coder.typeof:

https://www.mathworks.com/help/coder/ref/coder.typeof.html?s_tid=srchtitle