problem.delcuts
problem.delcuts |
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
problem.addcuts or
problem.loadcuts. 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
problem.delcuts(ibasis, itype, interp, delta, cutind)
Arguments
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ibasis
|
Ensures the basis will be valid if set to
1. If set to
0, cuts with non-basic slacks may be deleted.
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itype
|
User defined type of the cut to be deleted.
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interp
|
Way in which the cut
itype is interpreted:
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delta
|
Only delete cuts with an absolute slack value greater than
delta. To delete all the cuts, this argument should be set to
-xpress.infinity.
|
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cutind
|
Array containing the cuts which are to be deleted.
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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
problem.getcutlist command.
Related topics
problem.addcuts,
problem.delcpcuts,
problem.getcutlist,
problem.loadcuts, Section "Working with the cut manager" of the Xpress Optimizer reference manual.