XPRSiisstatus
Purpose
Returns statistics on the Irreducible Infeasible Sets (IIS) found so far by
XPRSiisfirst (
IIS),
XPRSiisnext (
IIS
-n) or
XPRSiisall (
IIS
-a).
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
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.
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