heur_fracdiving.c
Go to the documentation of this file.
22 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
46 #define DIVESET_DIVETYPES SCIP_DIVETYPE_INTEGRALITY | SCIP_DIVETYPE_SOS1VARIABLE /**< bit mask that represents all supported dive types */
47 #define DIVESET_ISPUBLIC TRUE /**< is this dive set publicly available (ie., can be used by other primal heuristics?) */
56 #define DEFAULT_MAXLPITERQUOT 0.05 /**< maximal fraction of diving LP iterations compared to node LP iterations */
58 #define DEFAULT_MAXDIVEUBQUOT 0.8 /**< maximal quotient (curlowerbound - lowerbound)/(cutoffbound - lowerbound)
60 #define DEFAULT_MAXDIVEAVGQUOT 0.0 /**< maximal quotient (curlowerbound - lowerbound)/(avglowerbound - lowerbound)
62 #define DEFAULT_MAXDIVEUBQUOTNOSOL 0.1 /**< maximal UBQUOT when no solution was found yet (0.0: no limit) */
63 #define DEFAULT_MAXDIVEAVGQUOTNOSOL 0.0 /**< maximal AVGQUOT when no solution was found yet (0.0: no limit) */
64 #define DEFAULT_BACKTRACK TRUE /**< use one level of backtracking if infeasibility is encountered? */
66 #define DEFAULT_LPRESOLVEDOMCHGQUOT 0.15 /**< percentage of immediate domain changes during probing to trigger LP resolve */
68 #define DEFAULT_ONLYLPBRANCHCANDS FALSE /**< should only LP branching candidates be considered instead of the slower but
179 SCIP_CALL( SCIPperformGenericDivingAlgorithm(scip, diveset, heurdata->sol, heur, result, nodeinfeasible, -1L, SCIP_DIVECONTEXT_SINGLE) );
184 /** calculate score and preferred rounding direction for the candidate variable; the best candidate maximizes the
201 /* 'round' in nonzero direction, i.e., fix the candidates neighbors in the conflict graph to zero */
211 * - if variable may be rounded in either both or neither direction, round corresponding to the fractionality
212 * - otherwise, round in the infeasible direction, because feasible direction is tried by rounding
245 * use a 1:SCIP_PROBINGSCORE_PENALTYRATIO chance for increasing the fractionality, i.e., the score.
247 if( SCIPrandomGetInt(SCIPdivesetGetRandnumgen(diveset), 0, SCIP_PROBINGSCORE_PENALTYRATIO) == 0 )
276 {
296 /* create a diveset (this will automatically install some additional parameters for the heuristic)*/
297 SCIP_CALL( SCIPcreateDiveset(scip, NULL, heur, HEUR_NAME, DEFAULT_MINRELDEPTH, DEFAULT_MAXRELDEPTH, DEFAULT_MAXLPITERQUOT,
298 DEFAULT_MAXDIVEUBQUOT, DEFAULT_MAXDIVEAVGQUOT, DEFAULT_MAXDIVEUBQUOTNOSOL, DEFAULT_MAXDIVEAVGQUOTNOSOL,
SCIP_Bool SCIPisEQ(SCIP *scip, SCIP_Real val1, SCIP_Real val2)
Definition: scip_numerics.c:438
Definition: type_result.h:33
Definition: struct_scip.h:59
public methods for memory management
Definition: type_heur.h:60
SCIP_RANDNUMGEN * SCIPdivesetGetRandnumgen(SCIP_DIVESET *diveset)
Definition: heur.c:700
SCIP_RETCODE SCIPperformGenericDivingAlgorithm(SCIP *scip, SCIP_DIVESET *diveset, SCIP_SOL *worksol, SCIP_HEUR *heur, SCIP_RESULT *result, SCIP_Bool nodeinfeasible, SCIP_Longint iterlim, SCIP_DIVECONTEXT divecontext)
Definition: heuristics.c:209
methods commonly used by primal heuristics
public methods for problem variables
LP diving heuristic that chooses fixings w.r.t. the fractionalities.
SCIP_RETCODE SCIPsetHeurInit(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEURINIT((*heurinit)))
Definition: scip_heur.c:185
public methods for numerical tolerances
SCIP_RETCODE SCIPcreateSol(SCIP *scip, SCIP_SOL **sol, SCIP_HEUR *heur)
Definition: scip_sol.c:320
static SCIP_DECL_DIVESETGETSCORE(divesetGetScoreFracdiving)
Definition: heur_fracdiving.c:191
Definition: struct_sol.h:64
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:108
SCIP_RETCODE SCIPincludeHeurFracdiving(SCIP *scip)
Definition: heur_fracdiving.c:276
void SCIPheurSetData(SCIP_HEUR *heur, SCIP_HEURDATA *heurdata)
Definition: heur.c:1350
Definition: type_retcode.h:33
Definition: struct_heur.h:88
public methods for primal heuristic plugins and divesets
public data structures and miscellaneous methods
int SCIPrandomGetInt(SCIP_RANDNUMGEN *randnumgen, int minrandval, int maxrandval)
Definition: misc.c:9945
SCIP_RETCODE SCIPsetHeurExit(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEUREXIT((*heurexit)))
Definition: scip_heur.c:201
Definition: struct_heur.h:58
SCIP_RETCODE SCIPcreateDiveset(SCIP *scip, SCIP_DIVESET **diveset, SCIP_HEUR *heur, const char *name, SCIP_Real minreldepth, SCIP_Real maxreldepth, SCIP_Real maxlpiterquot, SCIP_Real maxdiveubquot, SCIP_Real maxdiveavgquot, SCIP_Real maxdiveubquotnosol, SCIP_Real maxdiveavgquotnosol, SCIP_Real lpresolvedomchgquot, int lpsolvefreq, int maxlpiterofs, unsigned int initialseed, SCIP_Bool backtrack, SCIP_Bool onlylpbranchcands, SCIP_Bool ispublic, SCIP_Bool specificsos1score, SCIP_DECL_DIVESETGETSCORE((*divesetgetscore)), SCIP_DECL_DIVESETAVAILABLE((*divesetavailable)))
Definition: scip_heur.c:311
public methods for solutions
SCIP_RETCODE SCIPsetHeurCopy(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEURCOPY((*heurcopy)))
Definition: scip_heur.c:153
public methods for message output
SCIP_RETCODE SCIPsetHeurFree(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEURFREE((*heurfree)))
Definition: scip_heur.c:169
public methods for primal heuristics
Definition: objbenders.h:33
public methods for global and local (sub)problems
SCIP_Bool SCIPisFeasPositive(SCIP *scip, SCIP_Real val)
Definition: scip_numerics.c:850