TY - GEN A1 - Achterberg, Tobias A1 - Raack, Christian T1 - The MCF-Separator -- Detecting and Exploiting Multi-Commodity Flow Structures in MIPs N2 - Given a general mixed integer program (MIP), we automatically detect block structures in the constraint matrix together with the coupling by capacity constraints arising from multi-commodity flow formulations. We identify the underlying graph and generate cutting planes based on cuts in the detected network. Our implementation adds a separator to the branch-and-cut libraries of SCIP and CPLEX. We make use of the complemented mixed integer rounding framework (cMIR) but provide a special purpose aggregation heuristic that exploits the network structure. Our separation scheme speeds-up the computation for a large set of MIPs coming from network design problems by a factor of two on average. KW - mixed integer programming KW - network detection KW - cut-based inequalities KW - scip KW - cplex Y1 - 2009 UR - https://opus4.kobv.de/opus4-matheon/frontdoor/index/index/docId/669 UR - https://nbn-resolving.org/urn:nbn:de:0296-matheon-6699 ER -