Get the number of independent IIS in an infeasible LP problem.

Number of independent IIS found by Xpress Optimizer, or a negative value in case of error.

The following gets the number of IIS for a problem.

XPRBprob expl2;
int num;
expl2 = XPRBnewprob("example2");
   ...
XPRBlpoptimize(expl2, "");
if(XPRBgetlpstat(expl2)==XPRB_LP_INFEAS)
 num = XPRBgetnumiis(expl2);

This function returns the number of independent IIS (irreducible infeasible sets) of an infeasible LP or MIP problem. After retrieving the number of IIS, the variables and constraints in each set can be obtained with function XPRBgetiis.

XPRBgetiis, XPRBgetlpstat.