|Formulator||David Grove Joergensen, Thorsten Koch|
|Root LP Basis||stp3d.bas.gz|
3D Steiner Tree packing problem (VLSI routing problem in a multi-layer grid graph)
Alkis Vazacopoulos reports finding the first feasible solution of this instance using XPRESS 2006B.
This instance was solved by a first implementation of ParaSCIP using up to 2048 cores of HLRN-II(http://www.hlrn.de). ParaSCIP, mainly developed by Yuji Shinano, is an extension of SCIP and realizes a parallelization on a distributed memory computing environment. For being able to interrupt and warmstart the computations, ParaSCIP has a checkpoint mechanism. Therefore, selected subproblems are stored as warm start information, which allows to virtually run ParaSCIP, although the HLRN-II environment imposes a time limit of 48 hours per run. The problem was presolved several times with SCIP presolving techniques. After that, it took approximately 114 hours to solve this instance.