branch_pscost.h File Reference

Detailed Description

pseudo costs branching rule

Author

Tobias Achterberg

The pseudo costs branching rule selects the branching variable with respect to the so-called pseudo costs of the variables. Pseudo costs measure the average gain per unit in the objective function when the variable was branched on upwards or downwards, resp. The required information is updated at every node of the solving process.

The selected variable maximizes the expected gain of the dual bound in the created subtree.

For a more mathematical description and a comparison between the pseudo costs branching rule and other branching rules in SCIP, we refer to

Tobias Achterberg
Constraint Integer Programming
PhD Thesis, Technische Universität Berlin, 2007

Definition in file branch_pscost.h.

#include "scip/scip.h"

Go to the source code of this file.

Functions
SCIP_RETCODE	SCIPincludeBranchrulePscost (SCIP *scip)
SCIP_RETCODE	SCIPselectBranchVarPscost (SCIP *scip, SCIP_VAR **branchcands, SCIP_Real *branchcandssol, SCIP_Real *branchcandsscore, int nbranchcands, SCIP_VAR **var, SCIP_Real *brpoint)

Function Documentation

SCIP_RETCODE SCIPincludeBranchrulePscost

(

SCIP *

scip

)

creates the pseudo cost branching rule and includes it in SCIP

Parameters

scip	SCIP data structure

Definition at line 633 of file branch_pscost.c.

References BRANCHRULE_DESC, BRANCHRULE_MAXBOUNDDIST, BRANCHRULE_MAXDEPTH, BRANCHRULE_NAME, BRANCHRULE_NARYMAXDEPTH_DEFAULT, BRANCHRULE_NARYMINWIDTH_DEFAULT, BRANCHRULE_NARYWIDTHFAC_DEFAULT, BRANCHRULE_NCHILDREN_DEFAULT, BRANCHRULE_PRIORITY, BRANCHRULE_SCOREMAXWEIGHT_DEFAULT, BRANCHRULE_SCOREMINWEIGHT_DEFAULT, BRANCHRULE_SCORESUMWEIGHT_DEFAULT, BRANCHRULE_STRATEGIES, BRANCHRULE_STRATEGY_DEFAULT, FALSE, NULL, SCIP_CALL, SCIP_OKAY, SCIP_REAL_MAX, SCIPaddCharParam(), SCIPaddIntParam(), SCIPaddRealParam(), SCIPallocMemory, SCIPincludeBranchruleBasic(), SCIPinfinity(), SCIPsetBranchruleCopy(), SCIPsetBranchruleExecExt(), SCIPsetBranchruleExecLp(), SCIPsetBranchruleFree(), and TRUE.

Referenced by SCIP_DECL_BRANCHCOPY(), and SCIPincludeDefaultPlugins().

SCIP_RETCODE SCIPselectBranchVarPscost	(	SCIP *	scip,
		SCIP_VAR **	branchcands,
		SCIP_Real *	branchcandssol,
		SCIP_Real *	branchcandsscore,
		int	nbranchcands,
		SCIP_VAR **	var,
		SCIP_Real *	brpoint
	)

selects a branching variable, due to pseudo cost, from the given candidate array and returns this variable together with a branching point

Parameters

scip	SCIP data structure
branchcands	branching candidates
branchcandssol	solution value for the branching candidates
branchcandsscore	array of candidate scores
nbranchcands	number of branching candidates
var	pointer to store the variable to branch on, or NULL if none
brpoint	pointer to store the branching point for the branching variable, will be fractional for a discrete variable

Definition at line 692 of file branch_pscost.c.

References BRANCHRULE_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPfindBranchrule(), and selectBranchVar().