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 41 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_DESC
#define HEUR_DESC "LP rounding heuristic with infeasibility recovering" |
Definition at line 42 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_DISPCHAR
#define HEUR_DISPCHAR SCIP_HEURDISPCHAR_ROUNDING |
Definition at line 43 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_PRIORITY
#define HEUR_PRIORITY -1000 |
Definition at line 44 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_FREQ
#define HEUR_FREQ 1 |
Definition at line 45 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_FREQOFS
#define HEUR_FREQOFS 0 |
Definition at line 46 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_MAXDEPTH
#define HEUR_MAXDEPTH -1 |
Definition at line 47 of file heur_rounding.c.
Referenced by SCIPincludeHeurRounding().
◆ HEUR_TIMING
#define HEUR_TIMING SCIP_HEURTIMING_DURINGLPLOOP |
Definition at line 48 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 49 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 51 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 56 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 76 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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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 134 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 205 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 307 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 322 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 341 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 424 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 438 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 457 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 475 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 491 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 510 of file heur_rounding.c.
◆ SCIP_DECL_HEUREXEC()
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static |
execution method of primal heuristic
Definition at line 521 of file heur_rounding.c.