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XPRSchgbounds

Purpose
Used to change the bounds on columns in the matrix.
Topic area
Problem Modification
Synopsis
int XPRS_CC XPRSchgbounds(XPRSprob prob, int nbounds, const int colind[], const char bndtype[], const double bndval[]);
Arguments
prob 
The current problem.
nbounds 
Number of bounds to change.
colind 
Integer array of size nbounds containing the indices of the columns on which the bounds will change.
bndtype 
Character array of length nbounds indicating the type of bound to change:
U 
indicates change the upper bound;
L 
indicates change the lower bound;
B 
indicates change both bounds, i.e. fix the column.
bndval 
Double array of length nbounds giving the new bound values.
Example
The following changes column 0 of the current problem to have an upper bound of 0.5: 
colind[0] = 0;
bndtype[0] = 'U';
bndval[0] = 0.5;
XPRSchgbounds(prob,1,colind,bndtype,bndval);
See also examples addmipsol.c, fixbv.c, repair.c, roundint.c.
Further information
1. A column index may appear twice in the colind array so it is possible to change both the upper and lower bounds on a variable in one go.
2. XPRSchgbounds can be used from within callbacks to modify the local node bounds of a branch-and-bound search. In this case, the solver expects column indices to match the presolved problem. This function can be called from within the following callbacks: XPRSaddcbprenode, XPRSaddcbnodelpsolved, XPRSaddcboptnode, XPRSaddcbcutmgr.
3. The double constants XPRS_PLUSINFINITY and XPRS_MINUSINFINITY defined in the library header file can be used to represent plus and minus infinity respectively in the bound ( bndval) array.
4. If the upper bound on a binary variable is changed to be greater than 1 or the lower bound is changed to be less than 0 then the variable will become an integer variable.
Related topics
XPRSgetlb, XPRSgetub,

Parent Topic Console and Library Functions

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