example constraint handler for partial ordering constraints More...

#include <cons_partialordering.h>
#include "utils.h"
#include "parent_set_data.h"
#include <assert.h>
#include <string.h>

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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 "partial 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 -200
	priority of the constraint handler for constraint enforcing

#define	CONSHDLR_NAME "partialordering"

#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

#define	consRespropPartialOrdering NULL
	propagation conflict resolving method of constraint handler

Functions
static SCIP_RETCODE	PartialOrderingSeparate (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 (consCheckPartialOrdering)
	feasibility check method of constraint handler for integral solutions

static	SCIP_DECL_CONSCOPY (consCopyPartialOrdering)
	constraint copying method of constraint handler

static	SCIP_DECL_CONSDELETE (consDeletePartialOrdering)
	frees specific constraint data

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

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

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

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

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

static	SCIP_DECL_CONSPRINT (consPrintPartialOrdering)
	constraint display method of constraint handler

static	SCIP_DECL_CONSPROP (consPropPartialOrdering)
	domain propagation method of constraint handler

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

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

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

SCIP_RETCODE	SCIPcreateConsBasicPartialOrdering (SCIP scip, SCIP_CONS cons, const char name, int n, SCIP_VAR **vars, ParentSetData psd, SCIP_Bool minimal)
	creates and captures a partial ordering constraint with all its constraint flags set to their default values More...

SCIP_RETCODE	SCIPcreateConsPartialOrdering (SCIP scip, SCIP_CONS cons, const char name, int n, SCIP_VAR **vars, ParentSetData psd, SCIP_Bool minimal, 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 partial ordering constraint More...

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

Detailed Description

example constraint handler for partial ordering constraints

Author: Marc Pfetsch; James Cussens

We handle the following system of partial constraints:

$x_{ij} + x_{ji} \leq 1$ (symmetry inequalities - added initially) $x_{ij} + x_{jk} - x_{ik} \leq 1$ (triangle inequalities)

The partial order must be consistent with the arrow variables which are also in the constraint If minimal=TRUE, the partial order must be the minimal one consistent with the arrows (ie the ancestor relation)

Function Documentation

◆ PartialOrderingSeparate()

static SCIP_RETCODE PartialOrderingSeparate	(	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().

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◆ SCIPcreateConsBasicPartialOrdering()

SCIP_RETCODE SCIPcreateConsBasicPartialOrdering	(	SCIP *	scip,
		SCIP_CONS **	cons,
		const char *	name,
		int	n,
		SCIP_VAR ***	vars,
		ParentSetData *	psd,
		SCIP_Bool	minimal
	)

creates and captures a partial ordering constraint with all its constraint flags set to their default values

Note: the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons()

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
psd	contains arrow and parent set variables
minimal	whether the partial order must minimal while being consistent with arrows

References SCIPcreateConsPartialOrdering().

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◆ SCIPcreateConsPartialOrdering()

SCIP_RETCODE SCIPcreateConsPartialOrdering	(	SCIP *	scip,
		SCIP_CONS **	cons,
		const char *	name,
		int	n,
		SCIP_VAR ***	vars,
		ParentSetData *	psd,
		SCIP_Bool	minimal,
		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 partial 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
psd	contains arrow and parent set variables
minimal	whether the partial order must minimal while being consistent with arrows
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 addAncestorVariables(), and SCIPcreateConsBasicPartialOrdering().

◆ SCIPincludeConshdlrPartialOrdering()

SCIP_RETCODE SCIPincludeConshdlrPartialOrdering ( SCIP * scip )

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

Parameters

scip	SCIP data structure

Referenced by BN_includePlugins().

Macros

Functions

Detailed Description

Function Documentation

◆ PartialOrderingSeparate()

◆ SCIPcreateConsBasicPartialOrdering()

◆ SCIPcreateConsPartialOrdering()

◆ SCIPincludeConshdlrPartialOrdering()