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, 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
|
Type of the cut to be deleted.
|
|
interp
|
Way in which the cut itype is interpreted:
|
-1
|
delete 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.
Related topics
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