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XPRSdelcuts

XPRSdelcuts

Purpose
Deletes cuts from the matrix at the current node. Cuts from the parent node which have been automatically restored may be deleted as well as cuts added to the current node using XPRSaddcuts or XPRSloadcuts. The cuts to be deleted can be specified in a number of ways. If a cut is ruled out by any one of the criteria it will not be deleted.
Synopsis
int XPRS_CC XPRSdelcuts(XPRSprob prob, int ibasis, int itype, int interp, double delta, int num, const XPRScut mcutind[]);
Arguments
prob 
The current problem.
ibasis 
Ensures the basis will be valid if set to 1. If set to 0, cuts with non-basic slacks may be deleted.
itype 
User defined type of the cut to be deleted.
interp 
Way in which the cut itype is interpreted:
-1 
match all cut types;
1 
treat cut types as numbers;
2 
treat cut types as bit maps - delete if any bit matches any bit set in itype;
3 
treat cut types as bit maps - delete if all bits match those set in itype.
delta 
Only delete cuts with an absolute slack value greater than delta. To delete all the cuts, this argument should be set to XPRS_MINUSINFINITY.
num 
Number of cuts to drop if a list of cuts is provided. A value of -1 indicates all cuts.
mcutind 
Array containing pointers to the cuts which are to be deleted. This array may be NULL if num is set to -1 otherwise it has length num.
Further information
1. It is usually best to drop only those cuts with basic slacks, otherwise the basis will no longer be valid and it may take many iterations to recover an optimal basis. If the ibasis parameter is set to 1, this will ensure that cuts with non-basic slacks will not be deleted even if the other parameters specify that these cuts should be deleted. It is highly recommended that the ibasis parameter is always set to 1.
2. The cuts to be deleted can also be specified by the size of the slack variable for the cut. Only those cuts with a slack value greater than the delta parameter will be deleted.
3. A list of indices of the cuts to be deleted can also be provided. The list of active cuts at a node can be obtained with the XPRSgetcutlist command.
4. This function should be called only from within callback functions set by either XPRSaddcboptnode or XPRSaddcbcutmgr.
Related topics
XPRSaddcuts, XPRSdelcpcuts, XPRSgetcutlist, XPRSloadcuts, Section Working with the Cut Manager.

Parent Topic Console and Library Functions

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