[Scip] Regarding a MIP problem

[Tobias Achterberg]

Try the following:

constraints/linear/maxpresolpairrounds = 0
presolving/probing/maxrounds = 0
nodeselection/bfs/minplungedepth = 200
separating/cmir/freq = -1

This should give you the very bad solution of value 50 pretty fast. At
least this is what happens with my development version and CPLEX as LP
solver.

And when I set an objective limit to 4 (after read problem, enter "set
lim obj 4"), I was even able to solve the instance to optimality with
my current development version and CPLEX as LP solver in 2 minutes.


Best, Tobias


gaurav khanna wrote:
> Hi all,
> 
> I have tried to use SCIP with MOSEK to solve a 0-1 MIP problem. The
> problem has 54061 variables and 78326 constraints. The instance has been
> running for the last 3 hours using the standard parameter file scip.set.
> To reduce the running time of the solver, is there any way I can change
> the parameter values in the scip.set file to speedup the  solution.
> Are there any specific parameters which I should target? Also,
> I am ok with getting feasible solutions to the MIP which need not be
> globally optimal. Is there a way to do that using SCIP that is to get a
> feasible solution in a lesser amount of time without significant loss in
> quality as compared to the global optimal.
> 
> The problem instance (MPS) is present at
> 
> http://www.cse.ohio-state.edu/~khannag/prob_8_lc.mps
> 
> Regards
> Gaurav
> 
> 
> Gaurav Khanna
> Phd Student
> CSE Department,OSU
> 
> Phone (office):614-292-7036
> 
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-- 
Tobias Achterberg          Konrad-Zuse-Zentrum fuer
                           Informationstechnik Berlin
Tel: +49 (0)30 84185-301   Takustr. 7
Email: achterberg at zib.de   D-14195 Berlin, Germany