XPRBgetvarrng

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	upper cost;
XPRB_LCOST	lower cost.

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.

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XPRBgetvarrng

XPRBgetvarrng