GAMS World Forum

Posted: **Wed Jan 12, 2022 9:08 am**

Dear all,

I am solving an MIP problem. It is considerably large. While the gap reduces initially, (from 375 to 14 %). Beyond this, it does not move forward.

Can you please let me know, what can I do? I have already tried many cplex parameters. But are not fruitful.

log_file_reference.txt: This is the reference log file, where the gap is stuck at a certain percentage for a long time; (40.12 KiB) Downloaded 194 times

Solver is CPLEX

Posted: **Thu Jan 13, 2022 9:15 am**

MIP is a difficult (NP hard) problem class and there is no guarantee that you will be able to solve a MIP of this size to global optimality in reasonable time. You can work on the formulation etc. No easy solution.

-Michael

GAMS World Forum

Gap does not reduce beyond a certain percentage in a MIP

Gap does not reduce beyond a certain percentage in a MIP

Re: Gap does not reduce beyond a certain percentage in a MIP