primal and dual reduction type

Specifies whether primal reductions, dual reductions, both, or neither are performed during preprocessing.

Purpose

Primal and dual reduction type

API	Parameter Name	Name prior to V12.6.0
C	CPXPARAM_Preprocessing_Reduce	CPX_PARAM_REDUCE
C++	IloCplex::Param::Preprocessing::Reduce	Reduce (int)
Java	IloCplex.Param.Preprocessing.Reduce	Reduce (int)
.NET	Cplex.Param.Preprocessing.Reduce	Reduce (int)
OPL	reduce	reduce
Python	parameters.preprocessing.reduce	preprocessing.reduce
Interactive	preprocessing reduce	preprocessing reduce
Identifier	1057	1057

Description

Specifies whether primal reductions, dual reductions, both, or neither are performed during preprocessing. These preprocessing reductions are also known as presolve reductions.

If your application uses lazy constraints (for example, you have explicitly added lazy constraints to the model before optimization, or you have registered lazy constraints from a callback by means of a method or routine, such as CPXsetlazyconstraintcallbackfunc) then CPLEX turns off dual reductions.

Table 1. Values
Value	Symbol	Meaning
0	`CPX_PREREDUCE_NOPRIMALORDUAL`	No primal or dual reductions
1	`CPX_PREREDUCE_PRIMALONLY`	Only primal reductions
2	`CPX_PREREDUCE_DUALONLY`	Only dual reductions
3	`CPX_PREREDUCE_PRIMALANDDUAL`	Both primal and dual reductions; default