Hi everyone,

I am currently trying to solve this problem but I always got error. Could anyone please help me to solve the problem! Thank you :)

Hey mehmet, 

The exception you're encountering is from IBM ILOG CPLEX and specifically refers to error code 5002. This error occurs when you attempt to solve a mathematical optimization problem using CPLEX, but the problem's constraints or objective function involve a non-convex expression.

In your case, the error message states that variable 'q74' is not convex. Convexity is an important property in optimization problems as it allows for efficient and reliable solutions. CPLEX requires convexity to guarantee the correctness of its results.

Try either to review your model or to reformulate the problem. If you find that the non-convexity is necessary for your problem formulation, you may need to explore alternative modeling approaches.

Hope this helps a bit.