Initializing help system before first use

XPRSgetscaledinfeas

Purpose
Returns a list of scaled infeasible primal and dual variables for the original problem. If the problem is currently presolved, it is postsolved before the function returns.
Topic areas
LP, Numerics
Synopsis
int XPRS_CC XPRSgetscaledinfeas(XPRSprob prob, int *p_nprimalcols, int *p_nprimalrows, int *p_ndualrows, int *p_ndualcols, int x[], int slack[], int duals[], int djs[]);
Arguments
prob 
The current problem.
p_nprimalcols 
Number of primal infeasible variables.
p_nprimalrows 
Number of primal infeasible rows.
p_ndualrows 
Number of dual infeasible rows.
p_ndualcols 
Number of dual infeasible variables.
x 
Integer array of length p_nprimalcols where the primal infeasible variables will be returned. May be NULL if not required.
slack 
Integer array of length p_nprimalrows where the primal infeasible rows will be returned. May be NULL if not required.
duals 
Integer array of length p_ndualrows where the dual infeasible rows will be returned. May be NULL if not required.
djs 
Integer array of length p_ndualcols where the dual infeasible variables will be returned. May be NULL if not required.
Error value
422 
A solution is not available.
Related controls
Double
FEASTOL 
Tolerance on RHS.
OPTIMALITYTOL 
Reduced cost tolerance.

Example
In this example, XPRSgetscaledinfeas is first called with nulled integer arrays to get the number of infeasible entries. Then space is allocated for the arrays and the function is again called to fill them in. 
int *x, *slack, *duals, *djs, nprimalcols, nprimalrows, ndualrows, ndualcols;
...
XPRSgetscaledinfeas(prob, &nprimalcols, &nprimalrows, &ndualrows, &ndualcols,
                    NULL, NULL, NULL, NULL);

x = malloc(nprimalcols * sizeof(int));
slack = malloc(nprimalrows * sizeof(int));
duals = malloc(ndualrows * sizeof(int));
djs = malloc(ndualcols * sizeof(int));
XPRSgetscaledinfeas(prob, &nprimalcols, &nprimalrows, &ndualrows, &ndualcols,
                    x, slack, duals, djs);
Further information
1. This function applies to linear and convex quadratic (including second order conic) problems only.
2. If any of the last four arguments are set to NULL, the corresponding number of infeasibilities is still returned.
Related topics
XPRSgetinfeas, XPRSgetiisdata, XPRSiisall, XPRSiisclear, XPRSiisfirst, XPRSiisisolations, XPRSiisnext, XPRSiisstatus, XPRSiiswrite, IIS.

Parent Topic Console and Library Functions

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