Do not grow arrays incrementally in Embedded Coder: allocate the full size for them and fill them in.
You might need to assignin('base') for your variables; I am not at all sure that would be enough though.
Your code is not clear as to whether you expect those three variables to be "global": when you expand the variables inside the loop, are you expecting to always start with the 3 zeros each time the function is invoked, or are you expecting that the changed arrays will persist for the next execution of the function? If you are expecting the changed values to persist then you should be using "global" for the variables (and notice that your arrays would continue to grow because you always add on to the end of them no matter how big they started out.)
I suspect what you should be doing is using a From Workspace block to import the variables as signals and then include those signals as input ports to the function block. I am not sure whether you would also want a To Workspace block to save the variables afterwards; I suspect not.
