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XPRSgetpresolvemap

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Purpose

Returns the mapping of the row and column numbers from the presolve problem back to the original problem.

Synopsis

int XPRS_CC XPRSgetpresolvemap(XPRSprob prob, int rowmap[], int colmap[]);

Arguments

prob	The current problem.
rowmap	Integer array of length ROWS where the row maps will be returned.
colmap	Integer array of length COLS where the column maps will be returned.

Example

The following reads in a (Mixed) Integer Programming problem and gets the mapping for the rows and columns back to the original problem following optimization of the linear relaxation. The elimination operations of the presolve are turned off so that a one-to-one mapping between the presolve problem and the original problem.

XPRSreadprob(prob,"MyProb","");
XPRSsetintcontrol(prob,XPRS_PRESOLVEOPS,255);
XPRSmaxim(prob,"");
XPRSgetintattrib(prob,XPRS_COLS,&cols);
colmap = malloc(cols*sizeof(int));
XPRSgetintattrib(prob,XPRS_ROWS,&rows);
rowmap = malloc(rows*sizeof(int));
XPRSgetpresolvemap(prob,rowmap,colmap);

Further information

In order to get a one-to-one mappng between the presolve problem and the original problem the elimination operations of the presolve must be turned off using;

XPRSsetintcontrol(prob,XPRS_PRESOLVEOPS,255);

Related topics

Working with Presolve.

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