Detailed Description

LNS heuristic that tries to delimit the search region to a neighborhood in the constraint graph.

Author: Gregor Hendel

Graph Induced Neighborhood Search (GINS) is a Large Neighborhood Search Heuristic that attempts to improve an incumbent solution by fixing a suitable percentage of integer variables to the incumbent and solving the resulting, smaller and presumably easier sub-MIP.

Its search neighborhoods are based on distances in a bipartite graph \(G\) with the variables and constraints as nodes and an edge between a variable and a constraint, if the variable is part of the constraint. Given an integer \(k\), the \(k\)-neighborhood of a variable \(v\) in \(G\) is the set of variables, whose nodes are connected to \(v\) by a path not longer than \(2 \cdot k\). Intuitively, a judiciously chosen neighborhood size allows to consider a local portion of the overall problem.

An initial variable selection is made by randomly sampling different neighborhoods across the whole main problem. The neighborhood that offers the largest potential for improvement is selected to become the local search neighborhood, while all variables outside the neighborhood are fixed to their incumbent solution values.

GINS also supports a rolling horizon approach, during which several local neighborhoods are considered with increasing distance to the variable selected for the initial sub-problem. The rolling horizon approach ends if no improvement could be found or a sufficient part of the problem component variables has been part of at least one neighborhood.

Definition in file heur_gins.c.

#include "blockmemshell/memory.h"
#include "scip/heur_gins.h"
#include "scip/heuristics.h"
#include "scip/pub_heur.h"
#include "scip/pub_message.h"
#include "scip/pub_misc.h"
#include "scip/pub_misc_sort.h"
#include "scip/pub_sol.h"
#include "scip/pub_var.h"
#include "scip/scip_branch.h"
#include "scip/scip_cons.h"
#include "scip/scip_copy.h"
#include "scip/scip_general.h"
#include "scip/scip_heur.h"
#include "scip/scip_mem.h"
#include "scip/scip_message.h"
#include "scip/scip_nodesel.h"
#include "scip/scip_numerics.h"
#include "scip/scip_param.h"
#include "scip/scip_prob.h"
#include "scip/scip_randnumgen.h"
#include "scip/scip_sol.h"
#include "scip/scip_solve.h"
#include "scip/scip_solvingstats.h"
#include "scip/scip_timing.h"
#include <string.h>

Go to the source code of this file.

Data Structures
struct	RollingHorizon

struct	SolveLimits

Macros
#define	HEUR_NAME "gins"

#define	HEUR_DESC "gins works on k-neighborhood in a variable-constraint graph"

#define	HEUR_DISPCHAR 'K'

#define	HEUR_PRIORITY -1103000

#define	HEUR_FREQ 20

#define	HEUR_FREQOFS 8

#define	HEUR_MAXDEPTH -1

#define	HEUR_TIMING SCIP_HEURTIMING_AFTERNODE

#define	HEUR_USESSUBSCIP TRUE

#define	DEFAULT_NODESOFS 500

#define	DEFAULT_MAXNODES 5000

#define	DEFAULT_MINIMPROVE 0.01

#define	DEFAULT_MINNODES 50

#define	DEFAULT_MINFIXINGRATE 0.66

#define	DEFAULT_NODESQUOT 0.15

#define	DEFAULT_NWAITINGNODES 100

#define	DEFAULT_USELPROWS FALSE

#define	DEFAULT_COPYCUTS TRUE

#define	DEFAULT_BESTSOLLIMIT 3

#define	DEFAULT_FIXCONTVARS FALSE

#define	DEFAULT_POTENTIAL 'r'

#define	DEFAULT_MAXDISTANCE 3

#define	DEFAULT_RANDSEED 71

#define	DEFAULT_RELAXDENSECONSS FALSE

#define	DEFAULT_USEROLLINGHORIZON TRUE

#define	DEFAULT_ROLLHORIZONLIMFAC 0.4

Typedefs
typedef struct RollingHorizon	ROLLINGHORIZON

typedef struct SolveLimits	SOLVELIMITS

Functions
static SCIP_RETCODE	rollingHorizonCreate (SCIP scip, ROLLINGHORIZON *rollinghorizon)

static SCIP_RETCODE	rollingHorizonFree (SCIP scip, ROLLINGHORIZON *rollinghorizon)

static SCIP_Bool	rollingHorizonRunAgain (SCIP scip, ROLLINGHORIZON rollinghorizon, SCIP_HEURDATA *heurdata)

static void	rollingHorizonStoreDistances (SCIP scip, ROLLINGHORIZON rollinghorizon, int *distances)

static SCIP_Real	getPotential (SCIP scip, SCIP_HEURDATA heurdata, SCIP_SOL sol, SCIP_VAR *vars, int nvars)

static SCIP_Bool	isVariableInNeighborhood (SCIP_VAR var, int distances, int maxdistance)

static SCIP_RETCODE	fixNonNeighborhoodVariables (SCIP scip, SCIP_HEURDATA heurdata, ROLLINGHORIZON rollinghorizon, SCIP_SOL sol, SCIP_VAR vars, SCIP_VAR fixedvars, SCIP_Real fixedvals, int distances, int maxdistance, int *nfixings)

static SCIP_RETCODE	determineMaxDistance (SCIP scip, SCIP_HEURDATA heurdata, int distances, int choosevardistance)

static SCIP_Real	heurdataAvgDiscreteNeighborhoodSize (SCIP_HEURDATA *heurdata)

static SCIP_RETCODE	selectInitialVariable (SCIP scip, SCIP_HEURDATA heurdata, SCIP_VGRAPH vargraph, int distances, SCIP_VAR *selvar, int selvarmaxdistance)

static SCIP_RETCODE	selectNextVariable (SCIP scip, SCIP_HEURDATA heurdata, ROLLINGHORIZON rollinghorizon, int distances, SCIP_VAR *selvar, int selvarmaxdistance)

static SCIP_RETCODE	determineVariableFixings (SCIP scip, SCIP_VAR fixedvars, SCIP_Real fixedvals, int nfixings, SCIP_HEURDATA heurdata, ROLLINGHORIZON rollinghorizon, SCIP_Bool success)

static SCIP_RETCODE	createNewSol (SCIP scip, SCIP subscip, SCIP_VAR *subvars, SCIP_HEUR heur, SCIP_SOL subsol, SCIP_Bool success)

static SCIP_RETCODE	setLimits (SCIP subscip, SOLVELIMITS solvelimits)

static SCIP_RETCODE	setupSubScip (SCIP scip, SCIP subscip, SOLVELIMITS solvelimits, SCIP_HEUR heur)

static SCIP_RETCODE	determineLimits (SCIP scip, SCIP_HEUR heur, SOLVELIMITS solvelimits, SCIP_Bool runagain)

static void	updateFailureStatistic (SCIP scip, SCIP_HEURDATA heurdata)

static	SCIP_DECL_HEURCOPY (heurCopyGins)

static	SCIP_DECL_HEURFREE (heurFreeGins)

static	SCIP_DECL_HEURINIT (heurInitGins)

static	SCIP_DECL_HEUREXIT (heurExitGins)

static	SCIP_DECL_HEUREXEC (heurExecGins)

SCIP_RETCODE	SCIPincludeHeurGins (SCIP *scip)

Macro Definition Documentation

◆ HEUR_NAME

#define HEUR_NAME "gins"

Definition at line 69 of file heur_gins.c.

Referenced by updateFailureStatistic().

◆ HEUR_DESC

#define HEUR_DESC "gins works on k-neighborhood in a variable-constraint graph"

Definition at line 70 of file heur_gins.c.

◆ HEUR_DISPCHAR

#define HEUR_DISPCHAR 'K'

Definition at line 71 of file heur_gins.c.

◆ HEUR_PRIORITY

#define HEUR_PRIORITY -1103000

Definition at line 72 of file heur_gins.c.

◆ HEUR_FREQ

#define HEUR_FREQ 20

Definition at line 73 of file heur_gins.c.

◆ HEUR_FREQOFS

#define HEUR_FREQOFS 8

Definition at line 74 of file heur_gins.c.

◆ HEUR_MAXDEPTH

#define HEUR_MAXDEPTH -1

Definition at line 75 of file heur_gins.c.

◆ HEUR_TIMING

#define HEUR_TIMING SCIP_HEURTIMING_AFTERNODE

Definition at line 76 of file heur_gins.c.

◆ HEUR_USESSUBSCIP

#define HEUR_USESSUBSCIP TRUE

does the heuristic use a secondary SCIP instance?

Definition at line 77 of file heur_gins.c.

◆ DEFAULT_NODESOFS

#define DEFAULT_NODESOFS 500

number of nodes added to the contingent of the total nodes

Definition at line 79 of file heur_gins.c.

◆ DEFAULT_MAXNODES

#define DEFAULT_MAXNODES 5000

maximum number of nodes to regard in the subproblem

Definition at line 80 of file heur_gins.c.

◆ DEFAULT_MINIMPROVE

#define DEFAULT_MINIMPROVE 0.01

factor by which Gins should at least improve the incumbent

Definition at line 81 of file heur_gins.c.

◆ DEFAULT_MINNODES

#define DEFAULT_MINNODES 50

minimum number of nodes to regard in the subproblem

Definition at line 82 of file heur_gins.c.

◆ DEFAULT_MINFIXINGRATE

#define DEFAULT_MINFIXINGRATE 0.66

minimum percentage of integer variables that have to be fixed

Definition at line 83 of file heur_gins.c.

◆ DEFAULT_NODESQUOT

#define DEFAULT_NODESQUOT 0.15

subproblem nodes in relation to nodes of the original problem

Definition at line 84 of file heur_gins.c.

◆ DEFAULT_NWAITINGNODES

#define DEFAULT_NWAITINGNODES 100

number of nodes without incumbent change that heuristic should wait

Definition at line 85 of file heur_gins.c.

◆ DEFAULT_USELPROWS

#define DEFAULT_USELPROWS FALSE

should subproblem be created out of the rows in the LP rows, < otherwise, the copy constructors of the constraints handlers are used

Definition at line 86 of file heur_gins.c.

◆ DEFAULT_COPYCUTS

#define DEFAULT_COPYCUTS TRUE

if DEFAULT_USELPROWS is FALSE, then should all active cuts from the < cutpool of the original scip be copied to constraints of the subscip

Definition at line 89 of file heur_gins.c.

◆ DEFAULT_BESTSOLLIMIT

#define DEFAULT_BESTSOLLIMIT 3

limit on number of improving incumbent solutions in sub-CIP

Definition at line 92 of file heur_gins.c.

◆ DEFAULT_FIXCONTVARS

#define DEFAULT_FIXCONTVARS FALSE

should continuous variables outside the neighborhoods get fixed?

Definition at line 93 of file heur_gins.c.

◆ DEFAULT_POTENTIAL

#define DEFAULT_POTENTIAL 'r'

the reference point to compute the neighborhood potential: (r)oot or (p)seudo solution

Definition at line 94 of file heur_gins.c.

◆ DEFAULT_MAXDISTANCE

#define DEFAULT_MAXDISTANCE 3

maximum distance to selected variable to enter the subproblem, or -1 to select the distance that best approximates the minimum fixing rate from below

Definition at line 95 of file heur_gins.c.

◆ DEFAULT_RANDSEED

#define DEFAULT_RANDSEED 71

Definition at line 98 of file heur_gins.c.

◆ DEFAULT_RELAXDENSECONSS

#define DEFAULT_RELAXDENSECONSS FALSE

should dense constraints (at least as dense as 1 - minfixingrate) be ignored by connectivity graph?

Definition at line 99 of file heur_gins.c.

◆ DEFAULT_USEROLLINGHORIZON

#define DEFAULT_USEROLLINGHORIZON TRUE

should the heuristic solve a sequence of sub-MIP's around the first selected variable

Definition at line 102 of file heur_gins.c.

◆ DEFAULT_ROLLHORIZONLIMFAC

#define DEFAULT_ROLLHORIZONLIMFAC 0.4

limiting percentage for variables already used in sub-SCIPs to terminate rolling horizon approach

Definition at line 103 of file heur_gins.c.

Typedef Documentation

◆ ROLLINGHORIZON

typedef struct RollingHorizon ROLLINGHORIZON

Definition at line 133 of file heur_gins.c.

◆ SOLVELIMITS

typedef struct SolveLimits SOLVELIMITS

Definition at line 185 of file heur_gins.c.

Function Documentation

◆ rollingHorizonCreate()

static SCIP_RETCODE rollingHorizonCreate	(	SCIP *	scip,
		ROLLINGHORIZON **	rollinghorizon
	)

static

create a rolling horizon data structure

Parameters

scip	SCIP data structure
rollinghorizon	pointer to rolling horizon data structure

Definition at line 222 of file heur_gins.c.

◆ rollingHorizonFree()

static SCIP_RETCODE rollingHorizonFree	(	SCIP *	scip,
		ROLLINGHORIZON **	rollinghorizon
	)

static

free a rolling horizon data structure

Parameters

scip	SCIP data structure
rollinghorizon	pointer to rolling horizon data structure

Definition at line 246 of file heur_gins.c.

◆ rollingHorizonRunAgain()

static SCIP_Bool rollingHorizonRunAgain	(	SCIP *	scip,
		ROLLINGHORIZON *	rollinghorizon,
		SCIP_HEURDATA *	heurdata
	)

static

is there potential to run another iteration of the rolling horizon approach?

Parameters

scip	SCIP data structure
rollinghorizon	rolling horizon data structure
heurdata	heuristic data

Definition at line 268 of file heur_gins.c.

References RollingHorizon::distances, RollingHorizon::nnonreachable, RollingHorizon::nused, rollingHorizonStoreDistances(), SCIPgetNBinVars(), and SCIPgetNIntVars().

Referenced by selectNextVariable().

◆ rollingHorizonStoreDistances()

static void rollingHorizonStoreDistances	(	SCIP *	scip,
		ROLLINGHORIZON *	rollinghorizon,
		int *	distances
	)

static

store the distances from the selected variable permanently for the rolling horizon approach

Parameters

scip	SCIP data structure
rollinghorizon	rolling horizon data structure
distances	breadth-first distances indexed by Probindex of variables

Definition at line 285 of file heur_gins.c.

References BMScopyMemoryArray, RollingHorizon::distances, RollingHorizon::distancessize, getPotential(), RollingHorizon::lastdistance, RollingHorizon::nnonreachable, and SCIP_Real.

Referenced by determineVariableFixings(), and rollingHorizonRunAgain().

◆ getPotential()

static SCIP_Real getPotential	(	SCIP *	scip,
		SCIP_HEURDATA *	heurdata,
		SCIP_SOL *	sol,
		SCIP_VAR **	vars,
		int	nvars
	)

static

get the potential of a subset of variables (distance to a reference point such as the pseudo-solution or root LP solution)

Parameters

scip	SCIP data structure
heurdata	heuristic data
sol	solution
vars	variable array
nvars	length of variable array

Definition at line 308 of file heur_gins.c.

References RollingHorizon::distances, isVariableInNeighborhood(), NULL, REALABS, SCIP_Bool, SCIP_Real, SCIPerrorMessage, SCIPgetSolVal(), SCIPisInfinity(), SCIPisZero(), SCIPvarGetLbGlobal(), SCIPvarGetObj(), SCIPvarGetRootSol(), and SCIPvarGetUbGlobal().

Referenced by rollingHorizonStoreDistances(), and selectInitialVariable().

◆ isVariableInNeighborhood()

static SCIP_Bool isVariableInNeighborhood	(	SCIP_VAR *	var,
		int *	distances,
		int	maxdistance
	)

static

is the variable in the current neighborhood which is given by the breadth-first distances from a central variable?

Parameters

var	problem variable
distances	breadth-first distances indexed by Probindex of variables
maxdistance	maximum distance (inclusive) to be considered for neighborhoods

Definition at line 373 of file heur_gins.c.

References fixNonNeighborhoodVariables(), NULL, and SCIPvarGetProbindex().

Referenced by getPotential(), and selectInitialVariable().

◆ fixNonNeighborhoodVariables()

static SCIP_RETCODE fixNonNeighborhoodVariables	(	SCIP *	scip,
		SCIP_HEURDATA *	heurdata,
		ROLLINGHORIZON *	rollinghorizon,
		SCIP_SOL *	sol,
		SCIP_VAR **	vars,
		SCIP_VAR **	fixedvars,
		SCIP_Real *	fixedvals,
		int *	distances,
		int	maxdistance,
		int *	nfixings
	)

static

fixes variables in subproblem based on long breadth-first distances in variable graph

Parameters

scip	SCIP data structure
heurdata	heuristic data
rollinghorizon	rolling horizon data structure to save relevant information, or NULL if not needed
sol	solution in main SCIP for fixing values
vars	variables in the main SCIP
fixedvars	buffer to store variables that should be fixed
fixedvals	buffer to store fixing values for fixed variables
distances	breadth-first distances indexed by Probindex of variables
maxdistance	maximum distance (inclusive) to be considered for neighborhoods
nfixings	pointer to store number of fixed variables

Definition at line 389 of file heur_gins.c.

References determineMaxDistance(), RollingHorizon::distances, RollingHorizon::lastmaxdistance, RollingHorizon::niterations, NULL, RollingHorizon::nused, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPgetSolVal(), SCIPgetVarsData(), SCIPisGT(), SCIPisInfinity(), SCIPisLE(), SCIPisLT(), SCIPvarGetLbGlobal(), SCIPvarGetUbGlobal(), TRUE, and RollingHorizon::used.

Referenced by determineVariableFixings(), and isVariableInNeighborhood().

◆ determineMaxDistance()

static SCIP_RETCODE determineMaxDistance	(	SCIP *	scip,
		SCIP_HEURDATA *	heurdata,
		int *	distances,
		int *	choosevardistance
	)

static

determine the maximum allowed distance to stay within the restriction to fix at least minfixingrate many non neighborhood variables

Parameters

scip	SCIP data structure
heurdata	heuristic data
distances	breadth-first distances indexed by Probindex of variables
choosevardistance	pointer to store the computed maximum distance

Definition at line 462 of file heur_gins.c.

References heurdataAvgDiscreteNeighborhoodSize(), MAX, MIN, NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPduplicateBufferArray, SCIPfreeBufferArray, SCIPgetVarsData(), SCIPsortedvecFindInt(), and SCIPsortInt().

Referenced by fixNonNeighborhoodVariables(), selectInitialVariable(), and selectNextVariable().

◆ heurdataAvgDiscreteNeighborhoodSize()

static SCIP_Real heurdataAvgDiscreteNeighborhoodSize ( SCIP_HEURDATA * heurdata )

static

gets the average size of a discrete neighborhood over all variables tested

Parameters

heurdata heuristic data

Definition at line 518 of file heur_gins.c.

Referenced by determineMaxDistance(), and selectInitialVariable().

◆ selectInitialVariable()

static SCIP_RETCODE selectInitialVariable	(	SCIP *	scip,
		SCIP_HEURDATA *	heurdata,
		SCIP_VGRAPH *	vargraph,
		int *	distances,
		SCIP_VAR **	selvar,
		int *	selvarmaxdistance
	)

static

select a good starting variable at the first iteration of a rolling horizon approach

Parameters

scip	SCIP data structure
heurdata	heuristic data
vargraph	variable graph data structure to work on
distances	breadth-first distances indexed by Probindex of variables
selvar	pointer to store the selected variable
selvarmaxdistance	maximal distance k to consider for selected variable neighborhood

Definition at line 527 of file heur_gins.c.

References determineMaxDistance(), RollingHorizon::distances, getPotential(), heurdataAvgDiscreteNeighborhoodSize(), isVariableInNeighborhood(), MIN, NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIP_REAL_MIN, SCIPallocBufferArray, SCIPdebugMsg, SCIPduplicateBufferArray, SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetVarsData(), SCIPisPositive(), SCIPrandomGetInt(), SCIPvarGetName(), SCIPvarGetProbindex(), SCIPvariablegraphBreadthFirst(), SCIPvarIsActive(), SCIPvarIsIntegral(), and selectNextVariable().

Referenced by determineVariableFixings().

◆ selectNextVariable()

static SCIP_RETCODE selectNextVariable	(	SCIP *	scip,
		SCIP_HEURDATA *	heurdata,
		ROLLINGHORIZON *	rollinghorizon,
		int *	distances,
		SCIP_VAR **	selvar,
		int *	selvarmaxdistance
	)

static

select the next variable using the rolling horizon

Parameters

scip	SCIP data structure
heurdata	heuristic data
rollinghorizon	rolling horizon data structure to save relevant information, or NULL if not needed
distances	breadth-first distances indexed by Probindex of variables
selvar	pointer to store the selected variable
selvarmaxdistance	maximal distance k to consider for selected variable neighborhood

Definition at line 717 of file heur_gins.c.

References determineMaxDistance(), determineVariableFixings(), RollingHorizon::distances, RollingHorizon::lastdistance, RollingHorizon::lastmaxdistance, MIN, NULL, RollingHorizon::nused, rollingHorizonRunAgain(), SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPgetVarsData(), SCIPvarGetProbindex(), SCIPvariablegraphBreadthFirst(), TRUE, RollingHorizon::used, and RollingHorizon::variablegraph.

Referenced by determineVariableFixings(), and selectInitialVariable().

◆ determineVariableFixings()

static SCIP_RETCODE determineVariableFixings	(	SCIP *	scip,
		SCIP_VAR **	fixedvars,
		SCIP_Real *	fixedvals,
		int *	nfixings,
		SCIP_HEURDATA *	heurdata,
		ROLLINGHORIZON *	rollinghorizon,
		SCIP_Bool *	success
	)

static

determines the graph-induced variable fixings

Parameters

scip	original SCIP data structure
fixedvars	buffer to store variables that should be fixed
fixedvals	buffer to store fixing values for fixed variables
nfixings	pointer to store the number of fixed variables
heurdata	heuristic data
rollinghorizon	rolling horizon data structure to save relevant information, or NULL if not needed
success	used to store whether the creation of the subproblem worked

Definition at line 794 of file heur_gins.c.

References createNewSol(), RollingHorizon::distances, FALSE, fixNonNeighborhoodVariables(), RollingHorizon::lastmaxdistance, RollingHorizon::niterations, NULL, rollingHorizonStoreDistances(), SCIP_CALL, SCIP_OKAY, SCIPallocBufferArray, SCIPdebugMsg, SCIPfreeBufferArray, SCIPgetBestSol(), SCIPgetVarsData(), SCIPvarGetName(), SCIPvariablegraphBreadthFirst(), SCIPvariableGraphCreate(), SCIPvariableGraphFree(), selectInitialVariable(), selectNextVariable(), TRUE, and RollingHorizon::variablegraph.

Referenced by selectNextVariable().

◆ createNewSol()

static SCIP_RETCODE createNewSol	(	SCIP *	scip,
		SCIP *	subscip,
		SCIP_VAR **	subvars,
		SCIP_HEUR *	heur,
		SCIP_SOL *	subsol,
		SCIP_Bool *	success
	)

static

creates a new solution for the original problem by copying the solution of the subproblem

Parameters

scip	original SCIP data structure
subscip	SCIP structure of the subproblem
subvars	the variables of the subproblem
heur	gins heuristic structure
subsol	solution of the subproblem
success	used to store whether new solution was found or not

Definition at line 909 of file heur_gins.c.

References FALSE, NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPcreateSol(), SCIPfreeBufferArray, SCIPgetNOrigVars(), SCIPgetSolVals(), SCIPgetVarsData(), SCIPsetSolVals(), SCIPtrySolFree(), setLimits(), and TRUE.

Referenced by determineVariableFixings().

◆ setLimits()

static SCIP_RETCODE setLimits	(	SCIP *	subscip,
		SOLVELIMITS *	solvelimits
	)

static

set sub-SCIP solving limits

Parameters

subscip	SCIP data structure
solvelimits	pointer to solving limits data structure

Definition at line 955 of file heur_gins.c.

Referenced by createNewSol(), and setupSubScip().

◆ setupSubScip()

static SCIP_RETCODE setupSubScip	(	SCIP *	scip,
		SCIP *	subscip,
		SOLVELIMITS *	solvelimits,
		SCIP_HEUR *	heur
	)

static

set up the sub-SCIP

Parameters

scip	SCIP data structure
subscip	sub-SCIP data structure
solvelimits	pointer to solving limits data structure
heur	this heuristic

Definition at line 972 of file heur_gins.c.

References determineLimits(), FALSE, MIN, NULL, SCIP_Bool, SCIP_CALL, SCIP_OKAY, SCIP_PARAMSETTING_FAST, SCIP_PARAMSETTING_OFF, SCIP_Real, SCIPfindBranchrule(), SCIPfindConshdlr(), SCIPfindNodesel(), SCIPgetLowerbound(), SCIPgetUpperbound(), SCIPheurGetData(), SCIPisInfinity(), SCIPisParamFixed(), SCIPsetBoolParam(), SCIPsetCharParam(), SCIPsetIntParam(), SCIPsetObjlimit(), SCIPsetPresolving(), SCIPsetSeparating(), SCIPsetSubscipsOff(), SCIPsumepsilon(), setLimits(), and TRUE.

◆ determineLimits()

static SCIP_RETCODE determineLimits	(	SCIP *	scip,
		SCIP_HEUR *	heur,
		SOLVELIMITS *	solvelimits,
		SCIP_Bool *	runagain
	)

static

determine limits for a sub-SCIP

Parameters

scip	SCIP data structure
heur	this heuristic
solvelimits	pointer to solving limits data structure
runagain	can we solve another sub-SCIP with these limits

Definition at line 1072 of file heur_gins.c.

References FALSE, SolveLimits::memorylimit, MIN, SolveLimits::nodelimit, NULL, SCIP_CALL, SCIP_Longint, SCIP_OKAY, SCIP_Real, SCIPgetMemExternEstim(), SCIPgetMemUsed(), SCIPgetNNodes(), SCIPgetRealParam(), SCIPgetSolvingTime(), SCIPheurGetData(), SCIPheurGetNBestSolsFound(), SCIPisInfinity(), SolveLimits::timelimit, and updateFailureStatistic().

Referenced by setupSubScip().

◆ updateFailureStatistic()

static void updateFailureStatistic	(	SCIP *	scip,
		SCIP_HEURDATA *	heurdata
	)

static

updates heurdata after a run of GINS

Parameters

scip	original SCIP data structure
heurdata	primal heuristic data

Definition at line 1127 of file heur_gins.c.

References HEUR_NAME, MAX, NULL, SCIP_DECL_HEURCOPY(), SCIP_Real, SCIP_VERBLEVEL_HIGH, SCIPheurGetName(), and SCIPverbMessage().

Referenced by determineLimits().

◆ SCIP_DECL_HEURCOPY()

static SCIP_DECL_HEURCOPY ( heurCopyGins )

static

copy method for primal heuristic plugins (called when SCIP copies plugins)

Definition at line 1174 of file heur_gins.c.

Referenced by updateFailureStatistic().

◆ SCIP_DECL_HEURFREE()

static SCIP_DECL_HEURFREE ( heurFreeGins )

static

destructor of primal heuristic to free user data (called when SCIP is exiting)

Definition at line 1188 of file heur_gins.c.

◆ SCIP_DECL_HEURINIT()

static SCIP_DECL_HEURINIT ( heurInitGins )

static

initialization method of primal heuristic (called after problem was transformed)

Definition at line 1208 of file heur_gins.c.

◆ SCIP_DECL_HEUREXIT()

static SCIP_DECL_HEUREXIT ( heurExitGins )

static

initialization method of primal heuristic (called after problem was transformed)

Definition at line 1241 of file heur_gins.c.

◆ SCIP_DECL_HEUREXEC()

static SCIP_DECL_HEUREXEC ( heurExecGins )

static

execution method of primal heuristic

Definition at line 1269 of file heur_gins.c.

SCIP

Detailed Description

Data Structures

Macros

Typedefs

Functions

Macro Definition Documentation

◆ HEUR_NAME

◆ HEUR_DESC

◆ HEUR_DISPCHAR

◆ HEUR_PRIORITY

◆ HEUR_FREQ

◆ HEUR_FREQOFS

◆ HEUR_MAXDEPTH

◆ HEUR_TIMING

◆ HEUR_USESSUBSCIP

◆ DEFAULT_NODESOFS

◆ DEFAULT_MAXNODES

◆ DEFAULT_MINIMPROVE

◆ DEFAULT_MINNODES

◆ DEFAULT_MINFIXINGRATE

◆ DEFAULT_NODESQUOT

◆ DEFAULT_NWAITINGNODES

◆ DEFAULT_USELPROWS

◆ DEFAULT_COPYCUTS

◆ DEFAULT_BESTSOLLIMIT

◆ DEFAULT_FIXCONTVARS

◆ DEFAULT_POTENTIAL

◆ DEFAULT_MAXDISTANCE

◆ DEFAULT_RANDSEED

◆ DEFAULT_RELAXDENSECONSS

◆ DEFAULT_USEROLLINGHORIZON

◆ DEFAULT_ROLLHORIZONLIMFAC

Typedef Documentation

◆ ROLLINGHORIZON

◆ SOLVELIMITS

Function Documentation

◆ rollingHorizonCreate()

◆ rollingHorizonFree()

◆ rollingHorizonRunAgain()

◆ rollingHorizonStoreDistances()

◆ getPotential()

◆ isVariableInNeighborhood()

◆ fixNonNeighborhoodVariables()

◆ determineMaxDistance()

◆ heurdataAvgDiscreteNeighborhoodSize()

◆ selectInitialVariable()

◆ selectNextVariable()

◆ determineVariableFixings()

◆ createNewSol()

◆ setLimits()

◆ setupSubScip()

◆ determineLimits()

◆ updateFailureStatistic()

◆ SCIP_DECL_HEURCOPY()

◆ SCIP_DECL_HEURFREE()

◆ SCIP_DECL_HEURINIT()

◆ SCIP_DECL_HEUREXIT()

◆ SCIP_DECL_HEUREXEC()