[Scip] Fractional graph coloring - accessing solution of LP relaxation

Dimitri Sverdlov dimitri.sverdlov at inria.fr
Sat Dec 5 14:35:12 MET 2009


Hello again,

I am interested to see the solution of the LP relaxation of a graph 
coloring problem.

For that I modified the Coloring example by replacing the type of 
variables that are created
from SCIP_VARTYPE_CONTINUOUS to SCIP_VARTYPE_INTEGER. I also removed any 
preprocessing to keep things more simple.

Strangely, the solution value that I get with this fractional coloring 
application is not the same as the dual bound from the LP relaxation in 
the root node from the original coloring application. So I guess there 
is still something wrong with my modified application.

But I guess there must be a more simple way to get the solution of the 
LP relaxation. Is there a call similar to
SCIPgetBestSol(scip)
for that? I have already found the SCIPgetRootNode call, but I do not 
see how to get the LP solution from the SCIP_Node structure.

Thank you, best regards,
Dimitri



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