simplex perturbation switch

Decides whether to perturb problems.

Purpose

Simplex perturbation switch

API	Parameter Name	Name prior to V12.6.0
C	CPXPARAM_Simplex_Perturbation_Indicator	CPX_PARAM_PERIND
C++	IloCplex::Param::Simplex::Perturbation::Indicator	PerInd (bool)
Java	IloCplex.Param.Simplex.Perturbation.Indicator	PerInd (bool)
.NET	Cplex.Param.Simplex.Perturbation.Indicator	PerInd (bool)
OPL	perind	perind
Python	parameters.simplex.perturbation.indicator	simplex.perturbation
Interactive	simplex perturbationlimit	simplex perturbationlimit
Identifier	1027	1027

Description

Decides whether to perturb problems.

Setting this parameter to 1 (one) causes all problems to be automatically perturbed as optimization begins. A setting of 0 (zero) allows CPLEX to decide dynamically, during solution, whether progress is slow enough to merit a perturbation. The situations in which a setting of 1 (one) helps are rare and restricted to problems that exhibit extreme degeneracy.

In the Interactive Optimizer, the command


set simplex perturbationlimit

accepts two arguments and actually sets two parameters simultaneously. The first argument is a switch or indicator; its value is yes to turn on perturbation or no to turn off perturbation. The second argument is a constant value to set an amount of perturbation. See the parameter perturbation constant for more information about the value of this second argument.

Table 1. Values
Value	bool	Symbol	Interactive	Meaning
0	false	`CPX_OFF`	no	Automatic: let CPLEX choose; default
1	true	`CPX_ON`	yes	Turn on perturbation from beginning