Detailed Description
LP rounding heuristic that tries to recover from intermediate infeasibilities.
Definition in file heur_rounding.c.
#include "blockmemshell/memory.h"
#include "scip/heur_rounding.h"
#include "scip/pub_heur.h"
#include "scip/pub_lp.h"
#include "scip/pub_message.h"
#include "scip/pub_var.h"
#include "scip/scip_branch.h"
#include "scip/scip_heur.h"
#include "scip/scip_lp.h"
#include "scip/scip_mem.h"
#include "scip/scip_message.h"
#include "scip/scip_numerics.h"
#include "scip/scip_param.h"
#include "scip/scip_sol.h"
#include "scip/scip_solvingstats.h"
#include <string.h>
Go to the source code of this file.
Macros | |
#define | HEUR_NAME "rounding" |
#define | HEUR_DESC "LP rounding heuristic with infeasibility recovering" |
#define | HEUR_DISPCHAR SCIP_HEURDISPCHAR_ROUNDING |
#define | HEUR_PRIORITY -1000 |
#define | HEUR_FREQ 1 |
#define | HEUR_FREQOFS 0 |
#define | HEUR_MAXDEPTH -1 |
#define | HEUR_TIMING SCIP_HEURTIMING_DURINGLPLOOP |
#define | HEUR_USESSUBSCIP FALSE |
#define | DEFAULT_SUCCESSFACTOR 100 |
#define | DEFAULT_ONCEPERNODE FALSE |
Functions | |
static void | updateViolations (SCIP *scip, SCIP_ROW *row, SCIP_ROW **violrows, int *violrowpos, int *nviolrows, SCIP_Real oldactivity, SCIP_Real newactivity) |
static SCIP_RETCODE | updateActivities (SCIP *scip, SCIP_Real *activities, SCIP_ROW **violrows, int *violrowpos, int *nviolrows, int nlprows, SCIP_VAR *var, SCIP_Real oldsolval, SCIP_Real newsolval) |
static SCIP_RETCODE | selectRounding (SCIP *scip, SCIP_SOL *sol, SCIP_Real minobj, SCIP_ROW *row, int direction, SCIP_VAR **roundvar, SCIP_Real *oldsolval, SCIP_Real *newsolval) |
static SCIP_RETCODE | selectIncreaseRounding (SCIP *scip, SCIP_SOL *sol, SCIP_Real minobj, SCIP_ROW *row, SCIP_VAR **roundvar, SCIP_Real *oldsolval, SCIP_Real *newsolval) |
static SCIP_RETCODE | selectDecreaseRounding (SCIP *scip, SCIP_SOL *sol, SCIP_Real minobj, SCIP_ROW *row, SCIP_VAR **roundvar, SCIP_Real *oldsolval, SCIP_Real *newsolval) |
static SCIP_RETCODE | selectEssentialRounding (SCIP *scip, SCIP_SOL *sol, SCIP_Real minobj, SCIP_VAR **lpcands, int nlpcands, SCIP_VAR **roundvar, SCIP_Real *oldsolval, SCIP_Real *newsolval) |
static | SCIP_DECL_HEURCOPY (heurCopyRounding) |
static | SCIP_DECL_HEURFREE (heurFreeRounding) |
static | SCIP_DECL_HEURINIT (heurInitRounding) |
static | SCIP_DECL_HEUREXIT (heurExitRounding) |
static | SCIP_DECL_HEURINITSOL (heurInitsolRounding) |
static | SCIP_DECL_HEUREXITSOL (heurExitsolRounding) |
static | SCIP_DECL_HEUREXEC (heurExecRounding) |
SCIP_RETCODE | SCIPincludeHeurRounding (SCIP *scip) |
Macro Definition Documentation
◆ HEUR_NAME
#define HEUR_NAME "rounding" |
Definition at line 50 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_DESC
#define HEUR_DESC "LP rounding heuristic with infeasibility recovering" |
Definition at line 51 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_DISPCHAR
#define HEUR_DISPCHAR SCIP_HEURDISPCHAR_ROUNDING |
Definition at line 52 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_PRIORITY
#define HEUR_PRIORITY -1000 |
Definition at line 53 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_FREQ
#define HEUR_FREQ 1 |
Definition at line 54 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_FREQOFS
#define HEUR_FREQOFS 0 |
Definition at line 55 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_MAXDEPTH
#define HEUR_MAXDEPTH -1 |
Definition at line 56 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_TIMING
#define HEUR_TIMING SCIP_HEURTIMING_DURINGLPLOOP |
Definition at line 57 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_USESSUBSCIP
#define HEUR_USESSUBSCIP FALSE |
does the heuristic use a secondary SCIP instance?
Definition at line 58 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ DEFAULT_SUCCESSFACTOR
#define DEFAULT_SUCCESSFACTOR 100 |
number of calls per found solution that are considered as standard success, a higher factor causes the heuristic to be called more often
Definition at line 60 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ DEFAULT_ONCEPERNODE
#define DEFAULT_ONCEPERNODE FALSE |
should the heuristic only be called once per node?
Definition at line 65 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
Function Documentation
◆ updateViolations()
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static |
update row violation arrays after a row's activity value changed
- Parameters
-
scip SCIP data structure row LP row violrows array with currently violated rows violrowpos position of LP rows in violrows array nviolrows pointer to the number of currently violated rows oldactivity old activity value of LP row newactivity new activity value of LP row
Definition at line 85 of file heur_rounding.c.
References NULL, SCIP_Bool, SCIP_Real, SCIPisFeasGT(), SCIPisFeasLT(), SCIProwGetLhs(), SCIProwGetLPPos(), SCIProwGetRhs(), and updateActivities().
Referenced by updateActivities().
◆ updateActivities()
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static |
update row activities after a variable's solution value changed
- Parameters
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scip SCIP data structure activities LP row activities violrows array with currently violated rows violrowpos position of LP rows in violrows array nviolrows pointer to the number of currently violated rows nlprows number of rows in current LP var variable that has been changed oldsolval old solution value of variable newsolval new solution value of variable
Definition at line 143 of file heur_rounding.c.
References NULL, r, SCIP_OKAY, SCIP_Real, SCIPcolGetNLPNonz(), SCIPcolGetRows(), SCIPcolGetVals(), SCIPinfinity(), SCIPisInfinity(), SCIProwGetLPPos(), SCIProwIsInLP(), SCIProwIsLocal(), SCIPvarGetCol(), selectRounding(), and updateViolations().
Referenced by updateViolations().
◆ selectRounding()
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static |
returns a variable, that pushes activity of the row in the given direction with minimal negative impact on other rows; if variables have equal impact, chooses the one with best objective value improvement in corresponding direction; rounding in a direction is forbidden, if this forces the objective value over the upper bound
- Parameters
-
scip SCIP data structure sol primal solution minobj minimal objective value possible after rounding remaining fractional vars row LP row direction should the activity be increased (+1) or decreased (-1)? roundvar pointer to store the rounding variable, returns NULL if impossible oldsolval pointer to store old (fractional) solution value of rounding variable newsolval pointer to store new (rounded) solution value of rounding variable
Definition at line 214 of file heur_rounding.c.
References NULL, SCIP_LOCKTYPE_MODEL, SCIP_OKAY, SCIP_Real, SCIP_VARTYPE_BINARY, SCIP_VARTYPE_INTEGER, SCIPcolGetVar(), SCIPfeasCeil(), SCIPfeasFloor(), SCIPgetCutoffbound(), SCIPgetSolVal(), SCIPinfinity(), SCIPisFeasIntegral(), SCIProwGetCols(), SCIProwGetNLPNonz(), SCIProwGetVals(), SCIPvarGetNLocksDownType(), SCIPvarGetNLocksUpType(), SCIPvarGetObj(), SCIPvarGetType(), and selectIncreaseRounding().
Referenced by selectDecreaseRounding(), selectIncreaseRounding(), and updateActivities().
◆ selectIncreaseRounding()
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static |
returns a variable, that increases the activity of the row
- Parameters
-
scip SCIP data structure sol primal solution minobj minimal objective value possible after rounding remaining fractional vars row LP row roundvar pointer to store the rounding variable, returns NULL if impossible oldsolval old (fractional) solution value of rounding variable newsolval new (rounded) solution value of rounding variable
Definition at line 316 of file heur_rounding.c.
References selectDecreaseRounding(), and selectRounding().
Referenced by selectRounding().
◆ selectDecreaseRounding()
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static |
returns a variable, that decreases the activity of the row
- Parameters
-
scip SCIP data structure sol primal solution minobj minimal objective value possible after rounding remaining fractional vars row LP row roundvar pointer to store the rounding variable, returns NULL if impossible oldsolval old (fractional) solution value of rounding variable newsolval new (rounded) solution value of rounding variable
Definition at line 331 of file heur_rounding.c.
References selectEssentialRounding(), and selectRounding().
Referenced by selectIncreaseRounding().
◆ selectEssentialRounding()
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static |
returns a fractional variable, that has most impact on rows in opposite direction, i.e. that is most crucial to fix in the other direction; if variables have equal impact, chooses the one with best objective value improvement in corresponding direction; rounding in a direction is forbidden, if this forces the objective value over the upper bound
- Parameters
-
scip SCIP data structure sol primal solution minobj minimal objective value possible after rounding remaining fractional vars lpcands fractional variables in LP nlpcands number of fractional variables in LP roundvar pointer to store the rounding variable, returns NULL if impossible oldsolval old (fractional) solution value of rounding variable newsolval new (rounded) solution value of rounding variable
Definition at line 350 of file heur_rounding.c.
References NULL, SCIP_DECL_HEURCOPY(), SCIP_LOCKTYPE_MODEL, SCIP_OKAY, SCIP_Real, SCIP_VARTYPE_BINARY, SCIP_VARTYPE_INTEGER, SCIPfeasCeil(), SCIPfeasFloor(), SCIPgetCutoffbound(), SCIPgetSolVal(), SCIPinfinity(), SCIPisFeasIntegral(), SCIPvarGetNLocksDownType(), SCIPvarGetNLocksUpType(), SCIPvarGetObj(), and SCIPvarGetType().
Referenced by selectDecreaseRounding().
◆ SCIP_DECL_HEURCOPY()
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static |
copy method for primal heuristic plugins (called when SCIP copies plugins)
Definition at line 433 of file heur_rounding.c.
Referenced by selectEssentialRounding().
◆ SCIP_DECL_HEURFREE()
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static |
destructor of primal heuristic to free user data (called when SCIP is exiting)
Definition at line 447 of file heur_rounding.c.
◆ SCIP_DECL_HEURINIT()
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static |
initialization method of primal heuristic (called after problem was transformed)
Definition at line 466 of file heur_rounding.c.
◆ SCIP_DECL_HEUREXIT()
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static |
deinitialization method of primal heuristic (called before transformed problem is freed)
Definition at line 484 of file heur_rounding.c.
◆ SCIP_DECL_HEURINITSOL()
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static |
solving process initialization method of primal heuristic (called when branch and bound process is about to begin)
Definition at line 500 of file heur_rounding.c.
◆ SCIP_DECL_HEUREXITSOL()
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static |
solving process deinitialization method of primal heuristic (called before branch and bound process data is freed)
Definition at line 519 of file heur_rounding.c.
◆ SCIP_DECL_HEUREXEC()
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static |
execution method of primal heuristic
Definition at line 530 of file heur_rounding.c.