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) OPL symmetry 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