why my ga yields very high fval while very low best penalty value?

Hi i am trying to solve a mixed integer program using ga, while my solution is not feasible but the fval is very strange. First, it is a complex number, Secondly the best penalty value in my plot is a very very small number compared with fval.

[Walter Roberson]

You probably need some constraints to keep fval from going complex.

[BOWEN LI]

Thanks you so much Walter for answering me this and my previous question. Actually all my variables are set to be integers and have lower bound "0" and upper bound "1". And my functions as you saw in the attach files in my previous question are generating a value that should be greater than 0. And i also checked my “sqrt” equations, all are generating postive values. So in your opinion, what kind of constraints should be included? Thank you so much!