Initializing help system before first use

problem.storecuts

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 problem.loadcuts before they become active.
Synopsis
problem.storecuts(nodups, cuttype, rowtype, rhs, start, cutind, colind, cutcoef)
Arguments
nodups 
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.
cuttype 
Array containing the cut types. The cut types can be any integer and are used to identify the cuts.
rowtype 
Character array containing the row types:
L 
indicates a ≤ row;
E 
indicates an = row;
G 
indicates a ≥ row.
rhs 
Array containing the right hand side elements for the cuts.
start 
Array containing offsets into the colind and cutcoef arrays indicating the start of each cut. This array is of length ncuts+1 where ncuts is the length of rhs, with the last element start[ncuts] being where cut ncuts+1 would start.
cutind 
Array where the cuts will be returned.
colind 
Array containing the columns in the cuts.
cutcoef 
Array containing the matrix values for the cuts.
Further information
1. storecuts can be used to eliminate duplicate cuts. If the nodups 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 nodups is set to 2 the same test is carried out on all cuts, ignoring the cut type.
2. storecuts returns a list of the cuts added to the cut pool in the cutind array. If the cut is not added to the cut pool because a stronger cut exits a None will be returned. The cutind array can be passed directly to problem.loadcuts to load the most recently stored cuts into the matrix.
3. The columns and elements of the cuts must be stored contiguously in the colind and cutcoef arrays passed to storecuts. The starting point of each cut must be stored in the start array. To determine the length of the final cut the start array must be of length ncuts+1 with the last element of this array containing where the cut ncuts+1 would start.
Related topics
problem.loadcuts, Section "Working with the cut manager" of the Xpress Optimizer reference manual.

Parent Topic Xpress problem methods

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