The error occurs because 'discrete average model 3' is not a valid MATLAB function name. It contains spaces, which are not allowed.
In MATLAB, file names must start with a letter and can only contain alphanumeric characters and underscores. To fix it, rename the model or file to a valid name like 'discrete_average_model_3'. Also, check any subsystem or block names for invalid characters and update them. This should resolve the error during simulation or code generation.
I hope this helps!
