presolve dual setting

Decides whether CPLEX presolve should pass the primal or dual linear programming problem to the linear programming optimization algorithm.

Purpose

Presolve dual setting

API	Parameter Name	Name prior to V12.6.0
C	CPXPARAM_Preprocessing_Dual	CPX_PARAM_PREDUAL
C++	IloCplex::Param::Preprocessing::Dual	PreDual (int)
Java	IloCplex.Param.Preprocessing.Dual	PreDual (int)
.NET	Cplex.Param.Preprocessing.Dual	PreDual (int)
OPL	predual	predual
Python	parameters.preprocessing.dual	preprocessing.dual
Interactive	preprocessing dual	preprocessing dual
Identifier	1044	1044

Description

Decides whether CPLEX presolve should pass the primal or dual linear programming problem to the linear programming optimization algorithm. By default, CPLEX chooses automatically.

If this parameter is set to 1 (one), the CPLEX presolve algorithm is applied to the primal problem, but the resulting dual linear program is passed to the optimizer. This is a useful technique for problems with more constraints than variables.

When this parameter is set to 0 (zero, its default value) or 1 (one, turned on), CPLEX disables crushing and uncrushing of the model by such routines as CPXuncrushx. To use CPXuncrushx effectively, you must set the value of this parameter to -1, turning off this feature.

Table 1. Values
Value	Meaning
-1	Turn off this feature
0	Automatic: let CPLEX choose; default
1	Turn on this feature