heur_rounding.c
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31/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
60#define DEFAULT_SUCCESSFACTOR 100 /**< number of calls per found solution that are considered as standard success,
70 int successfactor; /**< number of calls per found solution that are considered as standard success,
207/** returns a variable, that pushes activity of the row in the given direction with minimal negative impact on other rows;
208 * if variables have equal impact, chooses the one with best objective value improvement in corresponding direction;
215 SCIP_Real minobj, /**< minimal objective value possible after rounding remaining fractional vars */
219 SCIP_Real* oldsolval, /**< pointer to store old (fractional) solution value of rounding variable */
276 if( (nlocks < minnlocks || deltaobj < bestdeltaobj) && minobj - obj < SCIPgetCutoffbound(scip) )
295 if( (nlocks < minnlocks || deltaobj < bestdeltaobj) && minobj + obj < SCIPgetCutoffbound(scip) )
317 SCIP_Real minobj, /**< minimal objective value possible after rounding remaining fractional vars */
332 SCIP_Real minobj, /**< minimal objective value possible after rounding remaining fractional vars */
342/** returns a fractional variable, that has most impact on rows in opposite direction, i.e. that is most crucial to
344 * if variables have equal impact, chooses the one with best objective value improvement in corresponding direction;
351 SCIP_Real minobj, /**< minimal objective value possible after rounding remaining fractional vars */
380 assert(SCIPvarGetType(var) == SCIP_VARTYPE_BINARY || SCIPvarGetType(var) == SCIP_VARTYPE_INTEGER);
393 if( (nlocks > maxnlocks || deltaobj < bestdeltaobj) && minobj - obj < SCIPgetCutoffbound(scip) )
409 if( (nlocks > maxnlocks || deltaobj < bestdeltaobj) && minobj + obj < SCIPgetCutoffbound(scip) )
496/** solving process initialization method of primal heuristic (called when branch and bound process is about to begin) */
515/** solving process deinitialization method of primal heuristic (called before branch and bound process data is freed) */
597 SCIPdebugMsg(scip, "executing rounding heuristic: %d LP rows, %d fractionals\n", nlprows, nfrac);
605 * the rows should be feasible, but due to numerical inaccuracies in the LP solver, they can be violated
643 bestroundval = obj > 0.0 ? SCIPfeasFloor(scip, lpcandssol[c]) : SCIPfeasCeil(scip, lpcandssol[c]);
654 SCIPdebugMsg(scip, "rounding heuristic: nfrac=%d, nviolrows=%d, obj=%g (best possible obj: %g)\n",
662 * - if a violated row exists, round a variable decreasing the violation, that has least impact on other rows
663 * - otherwise, round a variable, that has strongest devastating impact on rows in opposite direction
692 SCIP_CALL( selectEssentialRounding(scip, sol, minobj, lpcands, nlpcands, &roundvar, &oldsolval, &newsolval) );
720 SCIPdebugMsg(scip, "rounding heuristic: -> nfrac=%d, nviolrows=%d, obj=%g (best possible obj: %g)\n",
787 "number of calls per found solution that are considered as standard success, a higher factor causes the heuristic to be called more often",
SCIP_RETCODE SCIPaddIntParam(SCIP *scip, const char *name, const char *desc, int *valueptr, SCIP_Bool isadvanced, int defaultvalue, int minvalue, int maxvalue, SCIP_DECL_PARAMCHGD((*paramchgd)), SCIP_PARAMDATA *paramdata)
Definition: scip_param.c:83
SCIP_RETCODE SCIPaddBoolParam(SCIP *scip, const char *name, const char *desc, SCIP_Bool *valueptr, SCIP_Bool isadvanced, SCIP_Bool defaultvalue, SCIP_DECL_PARAMCHGD((*paramchgd)), SCIP_PARAMDATA *paramdata)
Definition: scip_param.c:57
SCIP_RETCODE SCIPincludeHeurRounding(SCIP *scip)
Definition: heur_rounding.c:760
SCIP_RETCODE SCIPgetLPBranchCands(SCIP *scip, SCIP_VAR ***lpcands, SCIP_Real **lpcandssol, SCIP_Real **lpcandsfrac, int *nlpcands, int *npriolpcands, int *nfracimplvars)
Definition: scip_branch.c:395
SCIP_RETCODE SCIPsetHeurExitsol(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEUREXITSOL((*heurexitsol)))
Definition: scip_heur.c:242
SCIP_RETCODE SCIPsetHeurCopy(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEURCOPY((*heurcopy)))
Definition: scip_heur.c:162
SCIP_RETCODE SCIPincludeHeurBasic(SCIP *scip, SCIP_HEUR **heur, const char *name, const char *desc, char dispchar, int priority, int freq, int freqofs, int maxdepth, SCIP_HEURTIMING timingmask, SCIP_Bool usessubscip, SCIP_DECL_HEUREXEC((*heurexec)), SCIP_HEURDATA *heurdata)
Definition: scip_heur.c:117
SCIP_RETCODE SCIPsetHeurFree(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEURFREE((*heurfree)))
Definition: scip_heur.c:178
SCIP_RETCODE SCIPsetHeurExit(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEUREXIT((*heurexit)))
Definition: scip_heur.c:210
SCIP_Longint SCIPheurGetNBestSolsFound(SCIP_HEUR *heur)
Definition: heur.c:1599
void SCIPheurSetTimingmask(SCIP_HEUR *heur, SCIP_HEURTIMING timingmask)
Definition: heur.c:1493
SCIP_RETCODE SCIPsetHeurInitsol(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEURINITSOL((*heurinitsol)))
Definition: scip_heur.c:226
SCIP_RETCODE SCIPsetHeurInit(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEURINIT((*heurinit)))
Definition: scip_heur.c:194
void SCIPheurSetData(SCIP_HEUR *heur, SCIP_HEURDATA *heurdata)
Definition: heur.c:1374
SCIP_RETCODE SCIPgetLPRowsData(SCIP *scip, SCIP_ROW ***rows, int *nrows)
Definition: scip_lp.c:570
SCIP_RETCODE SCIPcreateSol(SCIP *scip, SCIP_SOL **sol, SCIP_HEUR *heur)
Definition: scip_sol.c:184
SCIP_RETCODE SCIPprintSol(SCIP *scip, SCIP_SOL *sol, FILE *file, SCIP_Bool printzeros)
Definition: scip_sol.c:1631
SCIP_RETCODE SCIPtrySol(SCIP *scip, SCIP_SOL *sol, SCIP_Bool printreason, SCIP_Bool completely, SCIP_Bool checkbounds, SCIP_Bool checkintegrality, SCIP_Bool checklprows, SCIP_Bool *stored)
Definition: scip_sol.c:2954
SCIP_RETCODE SCIPsetSolVal(SCIP *scip, SCIP_SOL *sol, SCIP_VAR *var, SCIP_Real val)
Definition: scip_sol.c:1077
SCIP_Real SCIPgetSolVal(SCIP *scip, SCIP_SOL *sol, SCIP_VAR *var)
Definition: scip_sol.c:1217
SCIP_Real SCIPgetSolTransObj(SCIP *scip, SCIP_SOL *sol)
Definition: scip_sol.c:1347
SCIP_Real SCIPretransformObj(SCIP *scip, SCIP_Real obj)
Definition: scip_sol.c:1432
SCIP_Bool SCIPisGE(SCIP *scip, SCIP_Real val1, SCIP_Real val2)
Definition: scip_numerics.c:497
SCIP_Bool SCIPisLE(SCIP *scip, SCIP_Real val1, SCIP_Real val2)
Definition: scip_numerics.c:471
SCIP_Bool SCIPisFeasLT(SCIP *scip, SCIP_Real val1, SCIP_Real val2)
Definition: scip_numerics.c:793
SCIP_Bool SCIPisFeasIntegral(SCIP *scip, SCIP_Real val)
Definition: scip_numerics.c:881
SCIP_Bool SCIPisFeasGT(SCIP *scip, SCIP_Real val1, SCIP_Real val2)
Definition: scip_numerics.c:819
int SCIPvarGetNLocksUpType(SCIP_VAR *var, SCIP_LOCKTYPE locktype)
Definition: var.c:3353
int SCIPvarGetNLocksDownType(SCIP_VAR *var, SCIP_LOCKTYPE locktype)
Definition: var.c:3295
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)
Definition: heur_rounding.c:348
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)
Definition: heur_rounding.c:141
static void updateViolations(SCIP *scip, SCIP_ROW *row, SCIP_ROW **violrows, int *violrowpos, int *nviolrows, SCIP_Real oldactivity, SCIP_Real newactivity)
Definition: heur_rounding.c:83
static SCIP_RETCODE selectIncreaseRounding(SCIP *scip, SCIP_SOL *sol, SCIP_Real minobj, SCIP_ROW *row, SCIP_VAR **roundvar, SCIP_Real *oldsolval, SCIP_Real *newsolval)
Definition: heur_rounding.c:314
static SCIP_RETCODE selectDecreaseRounding(SCIP *scip, SCIP_SOL *sol, SCIP_Real minobj, SCIP_ROW *row, SCIP_VAR **roundvar, SCIP_Real *oldsolval, SCIP_Real *newsolval)
Definition: heur_rounding.c:329
static SCIP_DECL_HEUREXITSOL(heurExitsolRounding)
Definition: heur_rounding.c:517
static SCIP_DECL_HEURINITSOL(heurInitsolRounding)
Definition: heur_rounding.c:498
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)
Definition: heur_rounding.c:212
LP rounding heuristic that tries to recover from intermediate infeasibilities.
memory allocation routines
Definition: objbenders.h:44
public methods for primal heuristics
public methods for LP management
public methods for message output
public methods for problem variables
public methods for branching rule plugins and branching
public methods for primal heuristic plugins and divesets
public methods for the LP relaxation, rows and columns
public methods for memory management
public methods for message handling
public methods for numerical tolerances
public methods for SCIP parameter handling
public methods for solutions
public methods for querying solving statistics
Definition: struct_lp.h:136
Definition: struct_heur.h:98
Definition: struct_lp.h:202
Definition: struct_sol.h:74
Definition: struct_var.h:208
Definition: struct_scip.h:70