Error: Data 'regionDemand' (#28) is inferred as a variable size matrix, while its specified type is something else.

Hi,

I have specified the regionDemand matrix size within my matlab function block editor in simulink (user-defined function):

regionDemand = zeros(1,clusterCount);

where the value of clusterCount is obtained as an input into the function.

However, simulation of the code generated the error: Data 'regionDemand' (#28) is inferred as a variable size matrix, while its specified type is something else.

May I know how do I go about solving this? This is my first time using Simulink and there are many things which I have never come across before. Thanks a lot for helping!