Initializing help system before first use

XPRSiisall

Purpose
Performs an automated search for independent Irreducible Infeasible Sets (IIS) in an infeasible problem.
Topic area
Infeasibility
Synopsis
int XPRS_CC XPRSiisall(XPRSprob prob);
Argument
prob 
The current problem.
Related controls
Integer
MAXIIS 
Number of Irreducible Infeasible Sets to be found.

Example
This example searches for IISs and then queries the problem attribute NUMIIS to determine how many were found: 
int iis;
...
XPRSiisall(prob);
XPRSgetintattrib(prob, XPRS_NUMIIS, &iis);
printf("number of IISs = %d\n", iis);
Further information
1. This function applies to all problem types, including general nonlinear problems. For anything but linear problems its functionality is identical to XPRSiisfirst.
2. Calling IIS -a from the console has the same effect as this function.
3. A model may have several infeasibilities. Repairing a single IIS may not make the model feasible. For this reason the Optimizer can find an IIS for each of the infeasibilities in a model. If the control MAXIIS is set to a positive integer value then the XPRSiisall command will stop if MAXIIS IISs have been found. By default the control MAXIIS is set to -1, in which case an IIS is found for each of the infeasibilities in the model.
4. The problem attribute NUMIIS allows the user to recover the number of IISs found in a particular search. Alternatively, the XPRSiisstatus function may be used to retrieve the number of IISs found by XPRSiisfirst ( IIS), XPRSiisnext ( IIS -n) or XPRSiisall ( IIS -a) functions.
Related topics
XPRSgetiisdata, XPRSiisclear, XPRSiisfirst, XPRSiisisolations, XPRSiisnext, XPRSiisprint, XPRSiisstatus, XPRSiiswrite, IIS.

Parent Topic Console and Library Functions

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