heur_rootsoldiving.c
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27 * @brief LP diving heuristic that changes variable's objective values using root LP solution as guide
31/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
53#define HEUR_DESC "LP diving heuristic that changes variable's objective values using root LP solution as guide"
69#define DEFAULT_MAXLPITERQUOT 0.01 /**< maximal fraction of diving LP iterations compared to node LP iterations */
71#define DEFAULT_MAXSOLS -1 /**< total number of feasible solutions found up to which heuristic is called
73#define DEFAULT_DEPTHFAC 0.5 /**< maximal diving depth: number of binary/integer variables times depthfac */
74#define DEFAULT_DEPTHFACNOSOL 2.0 /**< maximal diving depth factor if no feasible solution was found yet */
86 SCIP_Real maxlpiterquot; /**< maximal fraction of diving LP iterations compared to node LP iterations */
90 SCIP_Real depthfac; /**< maximal diving depth: number of binary/integer variables times depthfac */
91 SCIP_Real depthfacnosol; /**< maximal diving depth factor if no feasible solution was found yet */
252 /* only try to dive, if we are in the correct part of the tree, given by minreldepth and maxreldepth */
263 maxnlpiterations = (SCIP_Longint)((1.0 + 10.0*(nsolsfound+1.0)/(ncalls+1.0)) * heurdata->maxlpiterquot * nlpiterations);
298 /* get current LP objective value, and calculate length of a single step in an objective coefficient */
304 /* initialize array storing the preferred soft rounding directions and counting the integral value rounds */
316 SCIPdebugMsg(scip, "(node %" SCIP_LONGINT_FORMAT ") executing rootsoldiving heuristic: depth=%d, %d fractionals, dualbound=%g, maxnlpiterations=%" SCIP_LONGINT_FORMAT ", maxdivedepth=%d, LPobj=%g, objstep=%g\n",
317 SCIPgetNNodes(scip), SCIPgetDepth(scip), nlpcands, SCIPgetDualbound(scip), maxnlpiterations, maxdivedepth,
348 SCIPdebugMsg(scip, "rootsoldiving found roundable primal solution: obj=%g\n", SCIPgetSolOrigObj(scip, heurdata->sol));
368 SCIPdebugMsg(scip, "dive %d/%d, LP iter %" SCIP_LONGINT_FORMAT "/%" SCIP_LONGINT_FORMAT ":\n", divedepth, maxdivedepth, heurdata->nlpiterations, maxnlpiterations);
390 /* if the variable became integral after a soft rounding, count the rounds; after a while, fix it to its
412 /* if the variable was soft rounded most of the time downwards, round it downwards by changing the bounds;
432 /* if the variable was soft rounded most of the time upwards, round it upwards by changing the bounds;
465 i, SCIPvarGetName(var), SCIPvarGetLPSol(var), rootsol[i], SCIPgetVarObjDive(scip, var), objchgvals[i]);
490 retcode = SCIPsolveDiveLP(scip, MAX((int)(maxnlpiterations - heurdata->nlpiterations), MINLPITER), &lperror, NULL);
493 /* Errors in the LP solver should not kill the overall solving process, if the LP is just needed for a heuristic.
494 * Hence in optimized mode, the return code is caught and a warning is printed, only in debug mode, SCIP will stop.
504 SCIPwarningMessage(scip, "Error while solving LP in Rootsoldiving heuristic; LP solve terminated with code <%d>\n", retcode);
505 SCIPwarningMessage(scip, "This does not affect the remaining solution procedure --> continue\n");
531 SCIPdebugMsg(scip, " -> opposite hard rounding <%s> >= %g\n", SCIPvarGetName(var), hardroundingnewbd + 1.0);
537 SCIPdebugMsg(scip, " -> opposite hard rounding <%s> <= %g\n", SCIPvarGetName(var), hardroundingnewbd - 1.0);
549 SCIPdebugMsg(scip, "---> diving finished: lpsolstat = %d, depth %d/%d, LP iter %" SCIP_LONGINT_FORMAT "/%" SCIP_LONGINT_FORMAT "\n",
559 SCIPdebugMsg(scip, "rootsoldiving found primal solution: obj=%g\n", SCIPgetSolOrigObj(scip, heurdata->sol));
SCIP_RETCODE SCIPgetVarsData(SCIP *scip, SCIP_VAR ***vars, int *nvars, int *nbinvars, int *nintvars, int *nimplvars, int *ncontvars)
Definition: scip_prob.c:1866
void SCIPwarningMessage(SCIP *scip, const char *formatstr,...)
Definition: scip_message.c:120
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 SCIPaddRealParam(SCIP *scip, const char *name, const char *desc, SCIP_Real *valueptr, SCIP_Bool isadvanced, SCIP_Real defaultvalue, SCIP_Real minvalue, SCIP_Real maxvalue, SCIP_DECL_PARAMCHGD((*paramchgd)), SCIP_PARAMDATA *paramdata)
Definition: scip_param.c:139
SCIP_RETCODE SCIPincludeHeurRootsoldiving(SCIP *scip)
Definition: heur_rootsoldiving.c:595
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
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 SCIPchgVarLbDive(SCIP *scip, SCIP_VAR *var, SCIP_Real newbound)
Definition: scip_lp.c:2419
SCIP_RETCODE SCIPchgVarUbDive(SCIP *scip, SCIP_VAR *var, SCIP_Real newbound)
Definition: scip_lp.c:2451
SCIP_RETCODE SCIPchgVarObjDive(SCIP *scip, SCIP_VAR *var, SCIP_Real newobj)
Definition: scip_lp.c:2378
SCIP_RETCODE SCIPsolveDiveLP(SCIP *scip, int itlim, SCIP_Bool *lperror, SCIP_Bool *cutoff)
Definition: scip_lp.c:2678
SCIP_RETCODE SCIPcreateSol(SCIP *scip, SCIP_SOL **sol, SCIP_HEUR *heur)
Definition: scip_sol.c:184
SCIP_RETCODE SCIProundSol(SCIP *scip, SCIP_SOL *sol, SCIP_Bool *success)
Definition: scip_sol.c:2311
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_Longint SCIPgetNNodeLPIterations(SCIP *scip)
Definition: scip_solvingstats.c:785
SCIP_Longint SCIPgetNLPIterations(SCIP *scip)
Definition: scip_solvingstats.c:446
SCIP_Bool SCIPisGE(SCIP *scip, SCIP_Real val1, SCIP_Real val2)
Definition: scip_numerics.c:497
SCIP_Bool SCIPisFeasIntegral(SCIP *scip, SCIP_Real val)
Definition: scip_numerics.c:881
static SCIP_DECL_HEURCOPY(heurCopyRootsoldiving)
Definition: heur_rootsoldiving.c:104
static SCIP_DECL_HEURFREE(heurFreeRootsoldiving)
Definition: heur_rootsoldiving.c:118
static SCIP_DECL_HEUREXIT(heurExitRootsoldiving)
Definition: heur_rootsoldiving.c:162
static SCIP_DECL_HEUREXEC(heurExecRootsoldiving)
Definition: heur_rootsoldiving.c:182
static SCIP_DECL_HEURINIT(heurInitRootsoldiving)
Definition: heur_rootsoldiving.c:138
LP diving heuristic that changes variables' objective values using root LP solution as guide.
memory allocation routines
Definition: objbenders.h:44
public methods for primal heuristics
public methods for message output
public methods for problem variables
public methods for branching rule plugins and branching
general public methods
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 global and local (sub)problems
public methods for solutions
public methods for querying solving statistics
public methods for the branch-and-bound tree
Definition: struct_heur.h:98
Definition: struct_sol.h:74
Definition: struct_var.h:208
Definition: struct_scip.h:70