[SCIP] How to check and separate only integer solutions in a constraint handler?

[Lastra Diaz Jose]

Dear all,

I am implementing a branch-and-Check approach to solve a 0-1 ILP model and I would like to check the feasibility of integer solutions, and insert a feasibility cut to separate those infeasible solutions. I have implemented a constraint handler based on the TSP example, but I have not understood well what callback I should implement. I have implemented the four separation and enforcement callback below, as done in TSP example, but when I check the solution in these callbacks, the solution is not binary. Likewise, I do not know how to skip non-integer solutions in the check callback.

What should I do to check and separate only infeasible integer solutions?

- SCIP_DECL_CONSSEPALP
- SCIP_DECL_CONSSEPASOL
- SCIP_DECL_CONSENFOLP
- SCIP_DECL_CONSENFOPS
- SCIP_DECL_CONSCHECK

ObjConshdlr(scip, "overdemand", "Feasibility cuts",
             1000000, -2000000, -2000000, 1, -1, 1, 0,
             FALSE, FALSE, TRUE, SCIP_PROPTIMING_BEFORELP, SCIP_PRESOLTIMING_FAST)


Thank you very much for your help,
Juan

[cid:image001.png at 01D4B3E6.540B6570]
Juan J. Lastra Díaz, PhD
Advanced Research department

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