[Scip] Gurobi LP interface

Eamonn Coughlan coughlan at math.TU-Berlin.DE
Thu Apr 22 12:53:15 MEST 2010


Hi all,

I've been using SCIP for a few different projects, and recently tried switching
from CPLEX and soplex to gurobi as an LP solver.
The following problem occurs: "ERROR: Gurobi cannot handle ranged rows.".
Some examination shows that this means any linear constraint with lhs < rhs.
I checked the gurobi docs and it appears there is a GRBaddrangeconstrs() call,
which appears to add equality constraints though.
What is the idiomatic way to deal with this?
Do i have to rewrite all my constraints (this would mean dealing with extra 
pricing variables depending on which solver i use, so i dislike this 
solution), or is there an easier way?
I noticed that constraints seem to be split as _lhs and _rhs automatically 
when i output my problem in LP format, so is there a way to get to these?
Or is there a plan to support these in lpi_grb	.c in the future?
I'd be willing to try this myself if there is no compelling reason why it 
can't be done there.

Regards,
Eamonn Coughlan


More information about the Scip mailing list