Initializing help system before first use

# problem.nextIIS

Purpose
Continues the search for further Irreducible Infeasible Sets (IIS), or calls problem.firstIIS if no IIS has been identified yet.
Topic areas
Infeasibility, Optimizer
Synopsis
`status = problem.nextIIS()`
Return value

status: int | The status after the search:
0 | success;
1 | no more IIS could be found, or problem is feasible if no problem.firstIIS call preceded;
2 | on error.

Further information
1. Returning multiple IISs is supported only for linear problems.
2. A model may have several infeasibilities. Repairing a single IIS may not make the model feasible. For this reason the Optimizer attempts to find an IIS for each of the infeasibilities in a model. You may call the problem.nextIIS function repeatedly, or use the problem.IISAll function to retrieve all IIS at once.
3. This function is not affected by the control MAXIIS.
4. If the problem has been modified since the last call to problem.firstIIS or problem.nextIIS, the generation process has to be started from scratch.
Related topics
problem.getIISData, problem.IISAll, problem.clearIIS, problem.firstIIS, problem.IISIsolations, problem.printIIS, problem.IISStatus, problem.writeIIS
Parent Topic Xpress problem object methods

© 2001-2026 Fair Isaac Corporation. All rights reserved. This documentation is the property of Fair Isaac Corporation (“FICO”). Receipt or possession of this documentation does not convey rights to disclose, reproduce, make derivative works, use, or allow others to use it except solely for internal evaluation purposes to determine whether to purchase a license to the software described in this documentation, or as otherwise set forth in a written software license agreement between you and FICO (or a FICO affiliate). Use of this documentation and the software described in it must conform strictly to the foregoing permitted uses, and no other use is permitted.