[Scip] how to solve a new IP during the branch and price

[michael.winkler@zib.de]

Hi,

for creating a new MIP inside SCIP you can use the following methods:

SCIP_CALL( SCIPcreate(&subscip) );
SCIP_CALL( SCIPincludeDefaultPlugins(subscip) );
... maybe change some parameters for your subscip
SCIP_CALL( SCIPcreateProb(...) );
SCIP_CALL( SCIPcreateVar(...) );
SCIP_CALL( SCIPaddVar(...) );
SCIP_CALL( SCIPreleaseVar(...) );
SCIP_CALL( SCIPcreateConsLinear(...) );
SCIP_CALL( SCIPaddCons(...) );
SCIP_CALL( SCIPreleaseCons(...) );

for solving you can call:
SCIP_CALL( SCIPpresolve(subscip) );
SCIP_CALL( SCIPsolve(subscip) );

and last but not least you should finish the subscip via:
SCIP_CALL( SCIPfree(&subscip) );

For examples creating subscips you can take a look at:
src/scip/heur_rens.c ,
src/scip/heur_crossover.c or
src/scip/sepa_zerohalf.c

Hope that will help.

Best, Michael

> Dear all,
>
> I develop a branch and price using SCIP and CPLEX as LP solver. To price
> out one column, I need to solve a new integer programming problem (IP),
> which is created based on the LP solution at each node of the
> branch-and-bound tree.
>
> I want to know whether I can use CPLEX's routine to create a new IP and
> solve it, since CPLEX is used as the LP solver.
>
>
> If not, is there any way in SCIP to create a new IP and solve it at each
> node in the branch-and-bound tree?
>
>
> Thanks.
>
>
> Xiangyong
>
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