9839 AGGREGATION and MIXED INTEGER ROUNDING toSOLVE

Aggregation and Mixed Integer Rounding to Solve MIPs

A separation heuristic for mixed integer programs is presented that theoretically allows one to derive several families of “strong” valid inequalities for specific models and computationally gives results as good as or better than those obtained from several existing separation routines including flow cover and integer cover inequalities. The heuristic is based on aggregation of constraints of ...

Monoidal Cut Strengthening and Generalized Mixed-Integer Rounding for Disjunctive Programs∗

This article investigates cutting planes for mixed-integer disjunctive programs. In the early 1980s, Balas and Jeroslow presented monoidal disjunctive cuts exploiting the integrality of variables. For disjunctions arising from binary variables, it is known that these cutting planes are essentially the same as Gomory mixed-integer and mixed-integer rounding cuts. In this article, we investigate ...

The Mcf-separator: detecting and exploiting multi-commodity flow structures in MIPs

Given a general mixed integer program, 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 mak...

Randomized Rounding: A Primal Heuristic for General Mixed Integer Programming Problems

We propose an algorithm for generating feasible solutions to general mixed-integer programming problems. Computational results demonstrating the effectiveness of the heuristic are given. The source code is available as a heuristic in the COIN-OR Branch Cut Solver at www.coin-or.org

Mixed integer rounding uts and master group polyhedra