Purpose
Get
ranging information for a variable.
Synopsis
double XPRBgetvarrng(XPRBvar var, int rngtype);
Arguments
|
var
|
BCL reference to a variable.
|
|
rngtype
|
The type of ranging information sought. This is one of:
|
XPRB_UPACT
|
upper
activity (= the activity level [solution value] that would result from a cost coefficient increase from the input cost to the upper cost XPRB_UCOST—assuming a minimization problem—ignoring the upper bound on this variable);
|
|
XPRB_LOACT
|
lower
activity (= the activity level [solution value] that would result from a cost coefficient decrease from the input cost to the lower cost XPRB_LCOST—assuming a minimization problem—ignoring the upper bound on this variable);
|
|
XPRB_UUP
|
upper
unit cost (= the change in the objective function per unit of change in the activity up to the upper activity XPRB_UPACT);
|
|
XPRB_UDN
|
lower
unit cost (= the change in the objective function per unit of change in the activity down to the lower activity XPRB_LOACT)
|
|
XPRB_UCOST
|
|
|
XPRB_LCOST
|
|
|
Return value
Ranging information of the required type.
Example
This example retrieves the upper cost value for a variable.
XPRBprob expl2;
XPRBvar x1;
double ucval;
expl2 = XPRBnewprob("example2");
x1 = XPRBnewvar(expl2, XPRB_UI, "abc3", 1, 100);
...
XPRBlpoptimize("expl2, "");
ucval = XPRBgetvarrng(x1, XPRB_UCOST);
Further information
1. This method can only be used after solving an LP problem. Ranging information for MIP problems can be obtained by fixing all discrete variables to their solution values (using
XPRSfixglobals) and re-solving the resulting LP problem.
2. For non-basic variables, the unit costs are always the (absolute) values of the reduced costs.
Related topics
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