Genetics Algorithm embedded into Simulink for simultaneous optimization.

Gents, Can someone help me out with a problem? I need to optimize material path destination (sort of integer problem), for different input variables which change over time.The objective function changes as a function of those parameters, and therefore likewise the optimum solution. I tried to use directly the GA call function in a the user defined matlab function block in Simulink but I obtained an error, related with "coder.extrinsic". If you have documents, pdf to figure out how to solve this problem I will be infinitely grateful. I would be even more if you can give me an advice. Thanks. Cristián.