example constraint handler for linear ordering constraints More...

#include "cons_lop.h"
#include <assert.h>
#include <string.h>

Include dependency graph for cons_lop.c:

Macros
#define	CONSHDLR_CHECKPRIORITY -100
	priority of the constraint handler for checking feasibility

#define	CONSHDLR_DELAYPROP FALSE
	should propagation method be delayed, if other propagators found reductions?

#define	CONSHDLR_DELAYSEPA FALSE
	should separation method be delayed, if other separators found cuts?

#define	CONSHDLR_DESC "linear ordering constraint handler"

#define	CONSHDLR_EAGERFREQ 100
	frequency for using all instead of only the useful constraints in separation, propagation and enforcement, -1 for no eager evaluations, 0 for first only

#define	CONSHDLR_ENFOPRIORITY -100
	priority of the constraint handler for constraint enforcing

#define	CONSHDLR_NAME "lop"

#define	CONSHDLR_NEEDSCONS TRUE
	should the constraint handler be skipped, if no constraints are available?

#define	CONSHDLR_PROP_TIMING SCIP_PROPTIMING_BEFORELP

#define	CONSHDLR_PROPFREQ 1
	frequency for propagating domains; zero means only preprocessing propagation

#define	CONSHDLR_SEPAFREQ 10
	frequency for separating cuts; zero means to separate only in the root node

#define	CONSHDLR_SEPAPRIORITY 100
	priority of the constraint handler for separation

Functions
static SCIP_RETCODE	LOPseparate (SCIP scip, SCIP_CONSHDLR conshdlr, int n, SCIP_VAR **vars, SCIP_SOL sol, int nGen, SCIP_Bool cutoff)
	separate symmetry equations and triangle inequalities More...

static	SCIP_DECL_CONSCHECK (consCheckLOP)
	feasibility check method of constraint handler for integral solutions

static	SCIP_DECL_CONSCOPY (consCopyLOP)
	constraint copying method of constraint handler

static	SCIP_DECL_CONSDELETE (consDeleteLOP)
	frees specific constraint data

static	SCIP_DECL_CONSENFOLP (consEnfolpLOP)
	constraint enforcing method of constraint handler for LP solutions

static	SCIP_DECL_CONSENFOPS (consEnfopsLOP)
	constraint enforcing method of constraint handler for pseudo solutions

static	SCIP_DECL_CONSEXIT (consExitLOP)
	deinitialization method of constraint handler (called before transformed problem is freed) More...

static	SCIP_DECL_CONSHDLRCOPY (conshdlrCopyLOP)
	copy method for constraint handler plugins (called when SCIP copies plugins)

static	SCIP_DECL_CONSINITLP (consInitlpLOP)
	LP initialization method of constraint handler.

static	SCIP_DECL_CONSLOCK (consLockLOP)
	variable rounding lock method of constraint handler

static	SCIP_DECL_CONSPRINT (consPrintLOP)
	constraint display method of constraint handler

static	SCIP_DECL_CONSPROP (consPropLOP)
	domain propagation method of constraint handler

static	SCIP_DECL_CONSRESPROP (consRespropLOP)
	propagation conflict resolving method of constraint handler

static	SCIP_DECL_CONSSEPALP (consSepalpLOP)
	separation method of constraint handler for LP solutions

static	SCIP_DECL_CONSSEPASOL (consSepasolLOP)
	separation method of constraint handler for arbitrary primal solutions

static	SCIP_DECL_CONSTRANS (consTransLOP)
	transforms constraint data into data belonging to the transformed problem

SCIP_RETCODE	SCIPcreateConsLOP (SCIP scip, SCIP_CONS cons, const char name, int n, SCIP_VAR ***vars, SCIP_Bool initial, SCIP_Bool separate, SCIP_Bool enforce, SCIP_Bool check, SCIP_Bool propagate, SCIP_Bool local, SCIP_Bool modifiable, SCIP_Bool dynamic, SCIP_Bool removable, SCIP_Bool stickingatnode)
	creates and captures a linear ordering constraint More...

SCIP_RETCODE	SCIPincludeConshdlrLOP (SCIP *scip)
	creates the handler for linear ordering constraints and includes it in SCIP More...

Detailed Description

example constraint handler for linear ordering constraints

Author: Marc Pfetsch

We handle the following system of linear constraints:

$x_{ij} + x_{ji} = 1$ (symmetry equations - added initially) $x_{ij} + x_{jk} + x_{ki} \leq 2$ (triangle inequalities)

Function Documentation

◆ LOPseparate()

static SCIP_RETCODE LOPseparate	(	SCIP *	scip,
		SCIP_CONSHDLR *	conshdlr,
		int	n,
		SCIP_VAR ***	vars,
		SCIP_SOL *	sol,
		int *	nGen,
		SCIP_Bool *	cutoff
	)

static

separate symmetry equations and triangle inequalities

Parameters

scip	SCIP pointer
conshdlr	constraint handler
n	number of elements
vars	n x n matrix of variables
sol	solution to be separated
nGen	output: pointer to store number of added rows
cutoff	output: pointer to store whether we detected a cutoff

References SCIP_DECL_CONSHDLRCOPY().

Here is the call graph for this function:

◆ SCIP_DECL_CONSEXIT()

static SCIP_DECL_CONSEXIT ( consExitLOP )

static

deinitialization method of constraint handler (called before transformed problem is freed)

We output the final linear ordering.

◆ SCIPcreateConsLOP()

SCIP_RETCODE SCIPcreateConsLOP	(	SCIP *	scip,
		SCIP_CONS **	cons,
		const char *	name,
		int	n,
		SCIP_VAR ***	vars,
		SCIP_Bool	initial,
		SCIP_Bool	separate,
		SCIP_Bool	enforce,
		SCIP_Bool	check,
		SCIP_Bool	propagate,
		SCIP_Bool	local,
		SCIP_Bool	modifiable,
		SCIP_Bool	dynamic,
		SCIP_Bool	removable,
		SCIP_Bool	stickingatnode
	)

creates and captures a linear ordering constraint

Parameters

scip	SCIP data structure
cons	pointer to hold the created constraint
name	name of constraint
n	number of elements
vars	n x n matrix of binary variables
initial	should the LP relaxation of constraint be in the initial LP?
separate	should the constraint be separated during LP processing?
enforce	should the constraint be enforced during node processing?
check	should the constraint be checked for feasibility?
propagate	should the constraint be propagated during node processing?
local	is constraint only valid locally?
modifiable	is constraint modifiable (subject to column generation)?
dynamic	is constraint subject to aging?
removable	should the relaxation be removed from the LP due to aging or cleanup?
stickingatnode	should the constraint always be kept at the node where it was added, even if it may be moved to a more global node?

Referenced by addTotalorderVariables().

◆ SCIPincludeConshdlrLOP()

SCIP_RETCODE SCIPincludeConshdlrLOP ( SCIP * scip )

creates the handler for linear ordering constraints and includes it in SCIP

Parameters

scip	SCIP data structure

Referenced by BN_includePlugins().

Macros

Functions

Detailed Description

Function Documentation

◆ LOPseparate()

◆ SCIP_DECL_CONSEXIT()

◆ SCIPcreateConsLOP()

◆ SCIPincludeConshdlrLOP()