Initializing help system before first use

XPRSiisstatus

Purpose
Returns statistics on the Irreducible Infeasible Sets (IIS) found so far by XPRSiisfirst ( IIS), XPRSiisnext ( IIS -n) or XPRSiisall ( IIS -a).
Topic area
Infeasibility
Synopsis
int XPRS_CC XPRSiisstatus(XPRSprob prob, int *p_niis, int nrows[], int ncols[], double suminfeas[], int numinfeas[]);
Arguments
prob 
The current problem.
p_niis 
The number of IISs found so far.
nrows 
Number of rows in the IISs.
ncols 
Number of bounds in the IISs.
suminfeas 
The sum of infeasibilities in the IISs after the first phase simplex.
numinfeas 
The number of infeasible variables in the IISs after the first phase simplex.
Example
This example first retrieves the number of IISs found so far, and then retrieves their main properties. Note that the arrays have size count+1, since the first index is reserved for the initial infeasible subset. 
XPRSiisstatus(myprob,&count,NULL,NULL,NULL,NULL);
nrows  = malloc((count+1)*sizeof(int));
ncols  = malloc((count+1)*sizeof(int));
suminfeas = malloc((count+1)*sizeof(double));
numinfeas = malloc((count+1)*sizeof(int));
XPRSiisstatus(myprob,&count,nrows,ncols,suminfeas,numinfeas);
Further information
1. Calling IIS -s from the console has the same effect as this function.
2. All arrays should be of dimension p_niis+1. The arrays are 0 based, index 0 corresponding to the initial infeasible subproblem.
3. The arrays may be NULL if not required.
4. For the initial infeasible problem (IIS 0) the subproblem size is returned (which may be different from the number of bounds), while for the IISs the number of bounds is returned (usually much smaller than the number of columns in the IIS).
5. Note that the values in suminfeas and numinfeas depend on the IIS, and in turn on the basis where the simplex algorithm has stopped. Different IISs can have different error measures.
6. p_niis is set to -1 if the search for IISs has not yet started.
Related topics
XPRSgetiisdata, XPRSiisall, XPRSiisclear, XPRSiisfirst, XPRSiisisolations, XPRSiisnext, XPRSiisprint, XPRSiiswrite, IIS.

Parent Topic Console and Library Functions

© 2001-2025 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.