SoPlex

 

If you want to use SoPlex you have to set the preprocessor flag ABACUS_SOPLEX during the compilation of your application. It is also required to switch to the new include file structure (see Section ) in order to avoid name conflicts.

Note, there are some restrictions of SoPlex in comparison with Cplex:

• SoPlex lacks a function for determining the reason for infeasible LP-relaxations that is required in some cases in a branch-and-cut-and-price algorithm. This feature is provided by the Cplex function CPXgetijdiv. Our experience shows that these cases happen rather seldomly. However, if such a case occurs, ABACUS has to stop the optimization. As long as not both cutting planes and columns are generated in the same algorithm this function is not required.
• SoPlex does not provide a barrier method.

SoPlex can be used free charge for academic users and first experiments show that its performance is competitive with commercial solvers. Unfortunately there is currently no support. We observed problems in very rare cases, i.e., SoPlex stopped reporting an internal error. SoPlex can be obtained from http://www.zib.de/Optimization/Software/Soplex/.