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XPRSstorecuts

Purpose

Stores cuts into the cut pool, but does not apply them to the current node. These cuts must be explicitly loaded into the matrix using XPRSloadcuts or XPRSsetbranchcuts before they become active.

Synopsis

               int XPRS_CC XPRSstorecuts(XPRSprob prob, int ncuts, int nodupl, const int mtype[], const char qrtype[], const double drhs[],
               const int mstart[], XPRScut mindex[], const int mcols[], const double dmatval[]);
               

Arguments

prob  

The current problem.

ncuts  

Number of cuts to add.

nodupl  

0	do not exclude duplicates from the cut pool;
1	duplicates are to be excluded from the cut pool;
2	duplicates are to be excluded from the cut pool, ignoring cut type.

mtype  

Integer array of length ncuts containing the cut types. The cut types can be any positive integer and are used to identify the cuts.

qrtype  

Character array of length ncuts containing the row types:

L	indicates a row;
E	indicates an = row;
G	indicates a row.

drhs  

Double array of length ncuts containing the right hand side elements for the cuts.

mstart  

Integer array containing offsets into the mcols and dmtval arrays indicating the start of each cut. This array is of length ncuts+1 with the last element mstart[ncuts] being where cut ncuts+1 would start.

mindex  

Array of length ncuts where the pointers to the cuts will be returned.

mcols  

Integer array of length mstart[ncuts]-1 containing the column indices in the cuts.

dmatval  

Double array of length mstart[ncuts]-1 containing the matrix values for the cuts.

Related Controls

Double

MATRIXTOL  
                     

Zero tolerance on matrix elements.

Further information

1. XPRSstorecuts can be used to eliminate duplicate cuts. If the nodupl parameter is set to 1, the cut pool will be checked for duplicate cuts with a cut type identical to the cuts being added. If a duplicate cut is found the new cut will only be added if its right hand side value makes the cut stronger. If the cut in the pool is weaker than the added cut it will be removed unless it has been applied to an active node of the tree. If nodupl is set to 2 the same test is carried out on all cuts, ignoring the cut type.

2. XPRSstorecuts returns a list of the cuts added to the cut pool in the mindex array. If the cut is not added to the cut pool because a stronger cut exits a NULL will be returned. The mindex array can be passed directly to XPRSloadcuts or XPRSsetbranchcuts to load the most recently stored cuts into the matrix.

3. The columns and elements of the cuts must be stored contiguously in the mcols and dmtval arrays passed to XPRSstorecuts. The starting point of each cut must be stored in the mstart array. To determine the length of the final cut the mstart array must be of length ncuts+1 with the last element of this array containing where the cut ncuts+1 would start.