symmetry breaking for MIP models

Decides whether MIP symmetry breaking reductions will be attempted during the preprocessing phase.

Purpose

Symmetry breaking

API Parameter Name Name prior to V12.6.0 C CPXPARAM_Preprocessing_Symmetry CPX_PARAM_SYMMETRY C++ IloCplex::Param::Preprocessing::Symmetry Symmetry (int) Java IloCplex.Param.Preprocessing.Symmetry Symmetry (int) .NET Cplex.Param.Preprocessing.Symmetry Symmetry (int) OPL symmetry symmetry Python parameters.preprocessing.symmetry preprocessing.symmetry Interactive preprocessing symmetry preprocessing symmetry Identifier 2059 2059

Description

Decides whether symmetry breaking reductions will be automatically executed, during the preprocessing phase, in a MIP model. The default level, -1, allows CPLEX to choose the degree of symmetry breaking to apply. The value 0 (zero) turns off symmetry breaking. Levels 1 through 5 apply increasingly aggressive symmetry breaking.

Table 1. Values

Value	Meaning
-1	Automatic: let CPLEX choose; default
0	Turn off symmetry breaking
1	Exert a moderate level of symmetry breaking
2	Exert an aggressive level of symmetry breaking
3	Exert a very aggressive level of symmetry breaking
4	Exert a highly aggressive level of symmetry breaking
5	Exert an extremely aggressive level of symmetry breaking