How can I implement recursion in code-generated Simulink models?

I am wanting to implement a recursive function call inside a "MATLAB Function" block in my Simulink model. However, it fails when I want to run in Rapid-Accelerator mode because recursive function calls are not allowed/supported in code-generation.

You can think of the function I am calling as listing a directory's content which should obviously recurse into child directories if there are any. The method being called is not implemented in the block itself but in an m-file on my userpath.

Is there a way to facilitate using recursive function calls inside a "MATLAB Function" block or do I have to design the block differently?

Answer 1

[Andrew Schenk]

As you are aware, recursion is not supported for Simulink Code Generation. An alternative algorithm design for this recursive directory list would be to use a while loop with a dynamic list of directories. An example is shown below, but note that this example needs some modifications to support code generation since Cell Arrays are not supported.

%the initial directory
directories = {'./'};
while numel(directories) > 0
  %the current directory
  currentDir = directories{end};
  %the current directory listing
  listing = dir(currentDir);
  %remove the current directory listing
  directories(end) = [];

    for i=1:numel(listing)
        if strcmp(listing(i).name, '.') || strcmp(listing(i).name, '..')
            %don't add the . or .. to the list
            continue;
        end
        disp(fullfile(currentDir, listing(i).name));
        if listing(i).isdir
            directories{end+1} = fullfile(currentDir, listing(i).name);
        end
    end
end

Answer 2

[Philipp Tempel]

Thank you Andrew, for the exemplary recursive code.

I will have to have a closer look into incorporating the code you provided into my recursive function (unfortunately it's not a function simple as getting the directory contents).

Are there really no ways to using recursive functions with code generation?

[chef13]

I am also interested in recursive functions with code generation.