Writing Penality function in GA

I am trying to solve a constrained optimization problem with two objectives using GA. The objective function and constraints are as follow:

min f1(x1, x2) & max f2(x1, x2)
subject to:
a*x1-b*x2 < 0 where a and b are constants
sum (x1)= 1

I want to use penalty function approach to solve this problem but I am not sure how to write and apply penalty function to both objectives. I would appreciate any help on this issue.

Answer 1

[Sebastian Castro]

You can use the gamultiobj function to pass in both your penalty functions separately.

https://www.mathworks.com/help/gads/gamultiobj.html

- Sebastian

[Saifullah Khalid]

Thanks, Sebastian Castro, Sorry I did not write requirement in question. Actually I am not clear how to write penalty function for this problem.