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How to lower relative and absolute gap?
Posted: Wed Jan 26, 2022 7:53 am
by seydaseyda
Hi everyone!
I added these two line to my model but it still gives me very big absolute gap and I can not trust my optimal result.
option optcr = 0;
Option optca=0;
How can i lower these gaps?
Re: How to lower relative and absolute gap?
Posted: Wed Jan 26, 2022 3:16 pm
by abhosekar
optcr and optca are tolerances that tell the solver when to stop. This has nothing to do with the absolute gap that solver achieves. You can set the tolerance however low you want, if the solver does not reach it, you will get bad results.
The answer lies in reformulating your problem and doing other things better. Setting optcr and optca is not the correct way.
- Atharv
Re: How to lower relative and absolute gap?
Posted: Wed Jan 26, 2022 4:04 pm
by seydaseyda
Hi,
okay and how can i reformulate my model? Which parts should I focus on especially?
Re: How to lower relative and absolute gap?
Posted: Wed Jan 26, 2022 5:18 pm
by abhosekar
That's a vague question. It is also a completely different question. Unfortunately, there is no answer without looking at your model. In fact, your model could actually be very difficult and lowering gap is not in your hands.
If you need further help, provide your entire code (may be in a separate thread) that can let other users reproduce this issue.
HTH.
-Atharv