Detailed Description
zirounding primal heuristic
Definition in file heur_zirounding.c.
#include "blockmemshell/memory.h"
#include "scip/heur_zirounding.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 "zirounding" |
#define | HEUR_DESC "LP rounding heuristic as suggested by C. Wallace taking row slacks and bounds into account" |
#define | HEUR_DISPCHAR SCIP_HEURDISPCHAR_ROUNDING |
#define | HEUR_PRIORITY -500 |
#define | HEUR_FREQ 1 |
#define | HEUR_FREQOFS 0 |
#define | HEUR_MAXDEPTH -1 |
#define | HEUR_TIMING SCIP_HEURTIMING_AFTERLPNODE |
#define | HEUR_USESSUBSCIP FALSE |
#define | DEFAULT_MAXROUNDINGLOOPS 2 |
#define | DEFAULT_STOPZIROUND TRUE |
#define | DEFAULT_STOPPERCENTAGE 0.02 |
#define | DEFAULT_MINSTOPNCALLS 1000 |
#define | MINSHIFT 1e-4 |
Typedefs | |
typedef enum Direction | DIRECTION |
Enumerations | |
enum | Direction { DIRECTION_UP = 1, DIRECTION_DOWN = -1, DIRECTION_NONE = 0, DIRECTION_UP = 1, DIRECTION_DOWN = -1 } |
Functions | |
static SCIP_Real | getZiValue (SCIP *scip, SCIP_Real val) |
static void | calculateBounds (SCIP *scip, SCIP_VAR *var, SCIP_Real currentvalue, SCIP_Real *upperbound, SCIP_Real *lowerbound, SCIP_Real *upslacks, SCIP_Real *downslacks, int nslacks, SCIP_Bool *numericalerror) |
static SCIP_RETCODE | updateSlacks (SCIP *scip, SCIP_SOL *sol, SCIP_VAR *var, SCIP_Real shiftvalue, SCIP_Real *upslacks, SCIP_Real *downslacks, SCIP_Real *activities, SCIP_VAR **slackvars, SCIP_Real *slackcoeffs, int nslacks) |
static void | rowFindSlackVar (SCIP *scip, SCIP_ROW *row, SCIP_VAR **varpointer, SCIP_Real *coeffpointer) |
static | SCIP_DECL_HEURCOPY (heurCopyZirounding) |
static | SCIP_DECL_HEURFREE (heurFreeZirounding) |
static | SCIP_DECL_HEURINIT (heurInitZirounding) |
static | SCIP_DECL_HEUREXIT (heurExitZirounding) |
static | SCIP_DECL_HEURINITSOL (heurInitsolZirounding) |
static | SCIP_DECL_HEUREXEC (heurExecZirounding) |
SCIP_RETCODE | SCIPincludeHeurZirounding (SCIP *scip) |
Macro Definition Documentation
◆ HEUR_NAME
#define HEUR_NAME "zirounding" |
Definition at line 50 of file heur_zirounding.c.
Referenced by SCIP_DECL_HEURCOPY(), SCIP_DECL_HEUREXEC(), SCIP_DECL_HEUREXIT(), SCIP_DECL_HEURFREE(), SCIP_DECL_HEURINIT(), SCIP_DECL_HEURINITSOL(), and SCIPincludeHeurZirounding().
◆ HEUR_DESC
#define HEUR_DESC "LP rounding heuristic as suggested by C. Wallace taking row slacks and bounds into account" |
Definition at line 51 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ HEUR_DISPCHAR
#define HEUR_DISPCHAR SCIP_HEURDISPCHAR_ROUNDING |
Definition at line 52 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ HEUR_PRIORITY
#define HEUR_PRIORITY -500 |
Definition at line 53 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ HEUR_FREQ
#define HEUR_FREQ 1 |
Definition at line 54 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ HEUR_FREQOFS
#define HEUR_FREQOFS 0 |
Definition at line 55 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ HEUR_MAXDEPTH
#define HEUR_MAXDEPTH -1 |
Definition at line 56 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ HEUR_TIMING
#define HEUR_TIMING SCIP_HEURTIMING_AFTERLPNODE |
Definition at line 57 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ HEUR_USESSUBSCIP
#define HEUR_USESSUBSCIP FALSE |
does the heuristic use a secondary SCIP instance?
Definition at line 58 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ DEFAULT_MAXROUNDINGLOOPS
#define DEFAULT_MAXROUNDINGLOOPS 2 |
delimits the number of main loops, can be set to -1 for no limit
Definition at line 60 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ DEFAULT_STOPZIROUND
#define DEFAULT_STOPZIROUND TRUE |
deactivation check is enabled by default
Definition at line 61 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ DEFAULT_STOPPERCENTAGE
#define DEFAULT_STOPPERCENTAGE 0.02 |
the tolerance percentage after which zirounding will not be executed anymore
Definition at line 62 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ DEFAULT_MINSTOPNCALLS
#define DEFAULT_MINSTOPNCALLS 1000 |
number of heuristic calls before deactivation check
Definition at line 63 of file heur_zirounding.c.
Referenced by SCIPincludeHeurZirounding().
◆ MINSHIFT
#define MINSHIFT 1e-4 |
minimum shift value for every single step
Definition at line 65 of file heur_zirounding.c.
Referenced by calculateBounds(), and SCIP_DECL_HEUREXEC().
Typedef Documentation
◆ DIRECTION
Definition at line 87 of file heur_zirounding.c.
Enumeration Type Documentation
◆ Direction
enum Direction |
Enumerator | |
---|---|
DIRECTION_UP | |
DIRECTION_DOWN | |
DIRECTION_NONE | |
DIRECTION_UP | |
DIRECTION_DOWN |
Definition at line 82 of file heur_zirounding.c.
Function Documentation
◆ getZiValue()
returns the fractionality of a value x, which is calculated as zivalue(x) = min(x-floor(x), ceil(x)-x)
- Parameters
-
scip pointer to current SCIP data structure val the value for which the fractionality should be computed
Definition at line 95 of file heur_zirounding.c.
References MIN, NULL, SCIP_Real, SCIPfeasCeil(), and SCIPfeasFloor().
Referenced by SCIP_DECL_HEUREXEC().
◆ calculateBounds()
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static |
determines shifting bounds for variable
- Parameters
-
scip pointer to current SCIP data structure var the variable for which lb and ub have to be calculated currentvalue the current value of var in the working solution upperbound pointer to store the calculated upper bound on the variable shift lowerbound pointer to store the calculated lower bound on the variable shift upslacks array that contains the slacks between row activities and the right hand sides of the rows downslacks array that contains lhs slacks nslacks current number of slacks numericalerror flag to determine whether a numerical error occurred
Definition at line 113 of file heur_zirounding.c.
References MAX, MIN, MINSHIFT, NULL, SCIP_Real, SCIPcolGetNLPNonz(), SCIPcolGetRows(), SCIPcolGetVals(), SCIPdebugMsg, SCIPinfinity(), SCIPisFeasLT(), SCIPisInfinity(), SCIProwGetLPPos(), SCIPvarGetCol(), SCIPvarGetLbGlobal(), SCIPvarGetUbGlobal(), and TRUE.
Referenced by SCIP_DECL_HEUREXEC().
◆ updateSlacks()
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static |
when a variable is shifted, the activities and slacks of all rows it appears in have to be updated
- Parameters
-
scip pointer to current SCIP data structure sol working solution var pointer to variable to be modified shiftvalue the value by which the variable is shifted upslacks upslacks of all rows the variable appears in downslacks downslacks of all rows the variable appears in activities activities of the LP rows slackvars the slack variables for equality rows slackcoeffs the slack variable coefficients nslacks size of the arrays
Definition at line 237 of file heur_zirounding.c.
References NULL, REALABS, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPcolGetNLPNonz(), SCIPcolGetRows(), SCIPcolGetVals(), SCIPgetSolVal(), SCIPisFeasEQ(), SCIPisFeasGE(), SCIPisFeasLE(), SCIPisInfinity(), SCIPisZero(), SCIProwGetLhs(), SCIProwGetLPPos(), SCIProwGetRhs(), SCIPsetSolVal(), SCIPvarGetCol(), SCIPvarGetLbGlobal(), and SCIPvarGetUbGlobal().
Referenced by SCIP_DECL_HEUREXEC().
◆ rowFindSlackVar()
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static |
finds a continuous slack variable for an equation row, NULL if none exists
- Parameters
-
scip pointer to current SCIP data structure row the row for which a slack variable is searched varpointer pointer to store the slack variable coeffpointer pointer to store the coefficient of the slack variable
Definition at line 328 of file heur_zirounding.c.
References NULL, SCIP_Real, SCIP_VARTYPE_CONTINUOUS, SCIPcolGetLPPos(), SCIPcolGetNLPNonz(), SCIPcolGetVar(), SCIPdebugMsg, SCIPisFeasEQ(), SCIProwGetCols(), SCIProwGetName(), SCIProwGetNNonz(), SCIProwGetVals(), SCIPvarGetLbGlobal(), SCIPvarGetName(), SCIPvarGetType(), and SCIPvarGetUbGlobal().
Referenced by SCIP_DECL_HEUREXEC().
◆ SCIP_DECL_HEURCOPY()
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static |
copy method for primal heuristic plugins (called when SCIP copies plugins)
Definition at line 387 of file heur_zirounding.c.
References HEUR_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPheurGetName(), and SCIPincludeHeurZirounding().
◆ SCIP_DECL_HEURFREE()
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static |
destructor of primal heuristic to free user data (called when SCIP is exiting)
Definition at line 401 of file heur_zirounding.c.
References HEUR_NAME, NULL, SCIP_OKAY, SCIPfreeBlockMemory, SCIPheurGetData(), SCIPheurGetName(), and SCIPheurSetData().
◆ SCIP_DECL_HEURINIT()
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static |
initialization method of primal heuristic (called after problem was transformed)
Definition at line 419 of file heur_zirounding.c.
References HEUR_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPcreateSol(), SCIPheurGetData(), and SCIPheurGetName().
◆ SCIP_DECL_HEUREXIT()
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static |
deinitialization method of primal heuristic (called before transformed problem is freed)
Definition at line 436 of file heur_zirounding.c.
References HEUR_NAME, NULL, SCIP_CALL, SCIP_OKAY, SCIPfreeSol(), SCIPheurGetData(), and SCIPheurGetName().
◆ 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 453 of file heur_zirounding.c.
References HEUR_NAME, NULL, SCIP_OKAY, SCIPheurGetData(), and SCIPheurGetName().
◆ SCIP_DECL_HEUREXEC()
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static |
execution method of primal heuristic
Definition at line 470 of file heur_zirounding.c.
References BMSclearMemoryArray, BMScopyMemoryArray, calculateBounds(), DIRECTION_DOWN, DIRECTION_UP, FALSE, getZiValue(), HEUR_NAME, MAX, MIN, MINSHIFT, NULL, r, rowFindSlackVar(), SCIP_Bool, SCIP_CALL, SCIP_DIDNOTFIND, SCIP_DIDNOTRUN, SCIP_FOUNDSOL, SCIP_Longint, SCIP_LPSOLSTAT_OPTIMAL, SCIP_OKAY, SCIP_Real, SCIP_VARSTATUS_COLUMN, SCIP_VARTYPE_BINARY, SCIP_VARTYPE_CONTINUOUS, SCIPallocBufferArray, SCIPcolGetLPPos(), SCIPcolGetNLPNonz(), SCIPcolGetRows(), SCIPdebugMsg, SCIPfeasCeil(), SCIPfeasFloor(), SCIPfreeBufferArrayNull, SCIPgetCutoffbound(), SCIPgetLPBranchCands(), SCIPgetLPObjval(), SCIPgetLPRows(), SCIPgetLPSolstat(), SCIPgetNLPRows(), SCIPgetNLPs(), SCIPgetRowActivity(), SCIPgetSolOrigObj(), SCIPgetSolVal(), SCIPhasCurrentNodeLP(), SCIPheurGetData(), SCIPheurGetName(), SCIPheurGetNCalls(), SCIPheurGetNSolsFound(), SCIPinfinity(), SCIPisFeasEQ(), SCIPisFeasGE(), SCIPisFeasIntegral(), SCIPisFeasLE(), SCIPisFeasLT(), SCIPisGE(), SCIPisInfinity(), SCIPisPositive(), SCIPisZero(), SCIPlinkLPSol(), SCIPprintSol(), SCIProwGetLhs(), SCIProwGetLPPos(), SCIProwGetName(), SCIProwGetRhs(), SCIPsetSolVal(), SCIPstatisticMessage, SCIPtrySol(), SCIPvarGetCol(), SCIPvarGetIndex(), SCIPvarGetLbGlobal(), SCIPvarGetName(), SCIPvarGetObj(), SCIPvarGetStatus(), SCIPvarGetType(), SCIPvarGetUbGlobal(), TRUE, and updateSlacks().