Simulink functions can be defined at various levels in the model hierarchy. For global accessibility, defining the function at the model's top level works best. However, a limitation exists where global Simulink functions cannot be directly called from Stateflow charts configured as reusable functions, as noted in the documentation:
To work around this while maintaining chart reusability, consider creating a local Simulink function within the Stateflow chart that calls the global function via a Function Caller block. For example, a global function named sumFunc can be accessed inside a local function localSumFunc using this approach:
This method supports code generation. For more details on reusing Simulink functions in Stateflow:
web(fullfile(docroot, 'stateflow/ug/simulink-functions-in-stateflow.html'))
