ilog.cplex
Class IloCplex.IIS

java.lang.Object
  |
  +--ilog.cplex.IloCplex.IIS

Enclosing class:

IloCplex

public static class IloCplex.IIS

extends java.lang.Object

An object of this class represents an irreducibly inconsistent set (IIS). These can be generated for an infeasible LP problem by using the method IloCplex.getIIS. Such objects can then be queried to identify the cause of the infeasibility.

An IIS is a part of the infeasible active model consisting only of those constraints (including bounds) necessary to maintain the infeasibility. In other words, removing any of the bounds or constraints of an IIS will cause the remaining problem to become feasible.

The IIS is represented as an explicit list of constraints participating in the IIS and a list of variable IIS statuses (type IloCplex.IIS.Status) indicating which bounds of each variable are relevant for the IIS. This information can be queried from an IIS object.

See Also:

IloCplex.getIIS(), IloCplex.IIS.Status

Nested Class Summary

static class

IloCplex.IIS.Status Enumeration of constraint and variable statuses in an IIS.

Method Summary

ilog.concert.IloConstraint[]	getConstraints() Returns the constraints in the IIS.
IloCplex.IIS.Status[]	getConstraintStatuses() Returns statuses of the constraints in the IIS.
ilog.concert.IloNumVar[]	getNumVars() Returns the variables in the IIS.
IloCplex.IIS.Status[]	getNumVarStatuses() Returns the statuses of the variables in the IIS.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getNumVars

public ilog.concert.IloNumVar[] getNumVars()

Returns the variables in the IIS. The corresponding statuses of these variables can be queried with the method getNumVarStatuses.

Returns:

The variables in the invoking IIS.

getNumVarStatuses

public IloCplex.IIS.Status[] getNumVarStatuses()

Returns the statuses of the variables in the IIS. If stat is the array returned by this method, stat[j] is the IIS status of variable getNumVars()[j] in the invoking IIS.

Returns:

The IIS statuses corresponding to the variables returned by the method getNumVars.

getConstraints

public ilog.concert.IloConstraint[] getConstraints()

Returns the constraints in the IIS. The corresponding statuses of these constraints can be queried with the method getConstraintStatuses.

Returns:

The constraints in the invoking IIS.

getConstraintStatuses

public IloCplex.IIS.Status[] getConstraintStatuses()

Returns statuses of the constraints in the IIS. If stat is the array returned by this method, stat[i] is the IIS status of constraint getConstraints()[i] in the invoking IIS.

Returns:

The IIS statuses corresponding to the constraints returned by the method getConstraints.