[SCIP] Pyscipopt conshdlr enforcement

[Besancon, Mathieu]

Dear Kody,


Just to clarify one thing in case this induced some confusion.

Constraint handlers are defined to add new constraints to the model, while separators would be the suitable mechanism for strengthening the LP relaxation (separators define the algorithms that produce cuts).


If a constraint handler is still what you think is suitable for your use case, did you implement all corresponding methods?


Best,
Mathieu

________________________________
From: Scip <scip-bounces at zib.de> on behalf of Kody Kazda <17kk18 at queensu.ca>
Sent: Sunday, November 17, 2024 4:37:27 PM
To: scip at zib.de
Subject: [SCIP] Pyscipopt conshdlr enforcement

Hi all,

I am looking to implement a constraint handler in pyscipopt to add strengthening cuts to tighten the LP relaxation before branching.
I have successfully implemented this on other models, but for some unknown reason on the model I am working with now I can’t get pyscipopt to enforce my constraint handler before branching.
SCIP will get to over 25,000 nodes and still not run my constraint handler.
I have tried all sorts of different enforcement priorities, going as high as 1E8, so that does not seem to be the issue.
Does anyone have any thoughts on what might be causing this issue?
Is there some algorithmic property that I am not considering that may cause SCIP to not enforce a high priority constraint handler prior to branching?

Thank you!
Kody
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