Scippy

SCIP

Solving Constraint Integer Programs

heur_rins.c
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4 /* SCIP --- Solving Constraint Integer Programs */
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24 
25 /**@file heur_rins.c
26  * @ingroup DEFPLUGINS_HEUR
27  * @brief LNS heuristic that combines the incumbent with the LP optimum
28  * @author Timo Berthold
29  */
30 
31 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
32 
33 #include "blockmemshell/memory.h"
34 #include "scip/heuristics.h"
35 #include "scip/heur_rins.h"
36 #include "scip/pub_event.h"
37 #include "scip/pub_heur.h"
38 #include "scip/pub_message.h"
39 #include "scip/pub_misc.h"
40 #include "scip/pub_sol.h"
41 #include "scip/pub_var.h"
42 #include "scip/scip_branch.h"
43 #include "scip/scip_cons.h"
44 #include "scip/scip_copy.h"
45 #include "scip/scip_event.h"
46 #include "scip/scip_general.h"
47 #include "scip/scip_heur.h"
48 #include "scip/scip_lp.h"
49 #include "scip/scip_mem.h"
50 #include "scip/scip_message.h"
51 #include "scip/scip_nodesel.h"
52 #include "scip/scip_numerics.h"
53 #include "scip/scip_param.h"
54 #include "scip/scip_prob.h"
55 #include "scip/scip_sol.h"
56 #include "scip/scip_solve.h"
57 #include "scip/scip_solvingstats.h"
58 #include <string.h>
59 
60 #define HEUR_NAME "rins"
61 #define HEUR_DESC "relaxation induced neighborhood search by Danna, Rothberg, and Le Pape"
62 #define HEUR_DISPCHAR SCIP_HEURDISPCHAR_LNS
63 #define HEUR_PRIORITY -1101000
64 #define HEUR_FREQ 25
65 #define HEUR_FREQOFS 0
66 #define HEUR_MAXDEPTH -1
67 #define HEUR_TIMING SCIP_HEURTIMING_AFTERLPNODE
68 #define HEUR_USESSUBSCIP TRUE /**< does the heuristic use a secondary SCIP instance? */
69 
70 #define DEFAULT_NODESOFS 500 /* number of nodes added to the contingent of the total nodes */
71 #define DEFAULT_MAXNODES 5000 /* maximum number of nodes to regard in the subproblem */
72 #define DEFAULT_MINNODES 50 /* minimum number of nodes to regard in the subproblem */
73 #define DEFAULT_MINIMPROVE 0.01 /* factor by which RINS should at least improve the incumbent */
74 #define DEFAULT_MINFIXINGRATE 0.3 /* minimum percentage of integer variables that have to be fixed */
75 #define DEFAULT_NODESQUOT 0.3 /* subproblem nodes in relation to nodes of the original problem */
76 #define DEFAULT_LPLIMFAC 2.0 /* factor by which the limit on the number of LP depends on the node limit */
77 #define DEFAULT_NWAITINGNODES 200 /* number of nodes without incumbent change that heuristic should wait */
78 #define DEFAULT_USELPROWS FALSE /* should subproblem be created out of the rows in the LP rows,
79  * otherwise, the copy constructors of the constraints handlers are used */
80 #define DEFAULT_COPYCUTS TRUE /* if DEFAULT_USELPROWS is FALSE, then should all active cuts from the cutpool
81  * of the original scip be copied to constraints of the subscip
82  */
83 #define DEFAULT_USEUCT FALSE /* should uct node selection be used at the beginning of the search? */
84 
85 /* event handler properties */
86 #define EVENTHDLR_NAME "Rins"
87 #define EVENTHDLR_DESC "LP event handler for " HEUR_NAME " heuristic"
88 
89 /*
90  * Data structures
91  */
92 
93 /** primal heuristic data */
94 struct SCIP_HeurData
95 {
96  int nodesofs; /**< number of nodes added to the contingent of the total nodes */
97  int maxnodes; /**< maximum number of nodes to regard in the subproblem */
98  int minnodes; /**< minimum number of nodes to regard in the subproblem */
99  SCIP_Real minfixingrate; /**< minimum percentage of integer variables that have to be fixed */
100  int nwaitingnodes; /**< number of nodes without incumbent change that heuristic should wait */
101  SCIP_Real minimprove; /**< factor by which RINS should at least improve the incumbent */
102  SCIP_Real nodelimit; /**< the nodelimit employed in the current sub-SCIP, for the event handler*/
103  SCIP_Real lplimfac; /**< factor by which the limit on the number of LP depends on the node limit */
104  SCIP_Longint usednodes; /**< nodes already used by RINS in earlier calls */
105  SCIP_Real nodesquot; /**< subproblem nodes in relation to nodes of the original problem */
106  SCIP_Bool uselprows; /**< should subproblem be created out of the rows in the LP rows? */
107  SCIP_Bool copycuts; /**< if uselprows == FALSE, should all active cuts from cutpool be copied
108  * to constraints in subproblem?
109  */
110  SCIP_Bool useuct; /**< should uct node selection be used at the beginning of the search? */
111 };
112 
113 /*
114  * Local methods
115  */
116 
117 
118 
119 
120 /** determines variable fixings for RINS
121  *
122  * RINS fixes variables with matching solution values in the current LP and the
123  * incumbent solution
124  */
125 static
127  SCIP* scip, /**< original SCIP data structure */
128  SCIP_VAR** fixedvars, /**< array to store source SCIP variables that should be fixed in the copy */
129  SCIP_Real* fixedvals, /**< array to store fixing values for variables that should be fixed in the copy */
130  int* nfixedvars, /**< pointer to store the number of variables that RINS can fix */
131  int fixedvarssize, /**< size of the buffer arrays to store potential fixings */
132  SCIP_Real minfixingrate, /**< percentage of integer variables that have to be fixed */
133  SCIP_Bool* success /**< pointer to store whether sufficiently many variable fixings were found */
134  )
135 {
136  SCIP_SOL* bestsol; /* incumbent solution of the original problem */
137  SCIP_VAR** vars; /* original scip variables */
138  SCIP_Real fixingrate;
139 
140  int nvars;
141  int nbinvars;
142  int nintvars;
143  int i;
144  int fixingcounter;
145 
146  assert(fixedvals != NULL);
147  assert(fixedvars != NULL);
148  assert(nfixedvars != NULL);
149 
150  /* get required data of the original problem */
151  SCIP_CALL( SCIPgetVarsData(scip, &vars, &nvars, &nbinvars, &nintvars, NULL, NULL) );
152  bestsol = SCIPgetBestSol(scip);
153  assert(bestsol != NULL);
154 
155  fixingcounter = 0;
156  assert(fixedvarssize >= nbinvars + nintvars);
157 
158  /* determine variables to fix in the subproblem */
159  for( i = 0; i < nbinvars + nintvars; i++ )
160  {
161  SCIP_Real lpsolval;
162  SCIP_Real solval;
163 
164  /* get the current LP solution and the incumbent solution for each variable */
165  lpsolval = SCIPvarGetLPSol(vars[i]);
166  solval = SCIPgetSolVal(scip, bestsol, vars[i]);
167 
168  /* iff both solutions are equal, variable is stored to be fixed */
169  if( SCIPisFeasEQ(scip, lpsolval, solval) )
170  {
171  /* store the fixing and increase the number of fixed variables */
172  fixedvars[fixingcounter] = vars[i];
173  fixedvals[fixingcounter] = solval;
174  fixingcounter++;
175  }
176  }
177 
178  /* store the number of fixings */
179  *nfixedvars = fixingcounter;
180 
181  /* abort, if all variables should be fixed */
182  if( fixingcounter == nbinvars + nintvars )
183  {
184  *success = FALSE;
185  return SCIP_OKAY;
186  }
187  else
188  fixingrate = (SCIP_Real)fixingcounter / (SCIP_Real)(MAX(nbinvars + nintvars, 1));
189 
190  /* abort, if the amount of fixed variables is insufficient */
191  if( fixingrate < minfixingrate )
192  {
193  *success = FALSE;
194  return SCIP_OKAY;
195  }
196 
197  *success = TRUE;
198  return SCIP_OKAY;
199 }
200 
201 static
202 SCIP_DECL_EVENTEXEC(eventExecRins);
203 
204 /** wrapper for the part of heuristic that runs a subscip. Wrapper is needed to avoid possible ressource leaks */
205 static
207  SCIP* scip, /**< original SCIP data structure */
208  SCIP* subscip, /**< SCIP structure of the subproblem */
209  SCIP_HEUR* heur, /**< Heuristic pointer */
210  SCIP_HEURDATA* heurdata, /**< Heuristic's data */
211  SCIP_VAR** vars, /**< original problem's variables */
212  SCIP_VAR** fixedvars, /**< Fixed variables of original SCIP */
213  SCIP_Real* fixedvals, /**< Fixed values of original SCIP */
214  SCIP_RESULT* result, /**< Result pointer */
215  int nvars, /**< Number of variables */
216  int nfixedvars, /**< Number of fixed variables */
217  SCIP_Longint nnodes /**< Number of nodes in the b&b tree */
218  )
219 {
220  SCIP_VAR** subvars; /* variables of the subscip */
221  SCIP_HASHMAP* varmapfw; /* hashmap for mapping between vars of scip and subscip */
222  SCIP_EVENTHDLR* eventhdlr; /* event handler for LP events */
223  SCIP_Real upperbound; /* upperbound of the original SCIP */
224  SCIP_Real cutoff; /* objective cutoff for the subproblem */
225 
226  SCIP_Bool success;
227 
228  int i;
229 
230  /* create the variable mapping hash map */
231  SCIP_CALL( SCIPhashmapCreate(&varmapfw, SCIPblkmem(subscip), nvars) );
232 
233  /* create a problem copy as sub SCIP */
234  SCIP_CALL( SCIPcopyLargeNeighborhoodSearch(scip, subscip, varmapfw, "rins", fixedvars, fixedvals, nfixedvars,
235  heurdata->uselprows, heurdata->copycuts, &success, NULL) );
236 
237  eventhdlr = NULL;
238  /* create event handler for LP events */
239  SCIP_CALL( SCIPincludeEventhdlrBasic(subscip, &eventhdlr, EVENTHDLR_NAME, EVENTHDLR_DESC, eventExecRins, NULL) );
240  if( eventhdlr == NULL )
241  {
242  SCIPerrorMessage("event handler for " HEUR_NAME " heuristic not found.\n");
243  return SCIP_PLUGINNOTFOUND;
244  }
245 
246  /* copy subproblem variables from map to obtain the same order */
247  SCIP_CALL( SCIPallocBufferArray(scip, &subvars, nvars) );
248  for( i = 0; i < nvars; i++ )
249  subvars[i] = (SCIP_VAR*) SCIPhashmapGetImage(varmapfw, vars[i]);
250 
251  /* free hash map */
252  SCIPhashmapFree(&varmapfw);
253 
254  /* do not abort subproblem on CTRL-C */
255  SCIP_CALL( SCIPsetBoolParam(subscip, "misc/catchctrlc", FALSE) );
256 
257 #ifdef SCIP_DEBUG
258  /* for debugging, enable full output */
259  SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", SCIP_VERBLEVEL_FULL) );
260  SCIP_CALL( SCIPsetIntParam(subscip, "display/freq", 100000000) );
261 #else
262  /* disable statistic timing inside sub SCIP and output to console */
263  SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", (int) SCIP_VERBLEVEL_NONE) );
264  SCIP_CALL( SCIPsetBoolParam(subscip, "timing/statistictiming", FALSE) );
265 #endif
266 
267  /* set limits for the subproblem */
268  SCIP_CALL( SCIPcopyLimits(scip, subscip) );
269  heurdata->nodelimit = nnodes;
270  SCIP_CALL( SCIPsetLongintParam(subscip, "limits/nodes", nnodes) );
271  SCIP_CALL( SCIPsetLongintParam(subscip, "limits/stallnodes", MAX(10, nnodes/10)) );
272  SCIP_CALL( SCIPsetIntParam(subscip, "limits/bestsol", 3) );
273 
274  /* forbid recursive call of heuristics and separators solving subMIPs */
275  SCIP_CALL( SCIPsetSubscipsOff(subscip, TRUE) );
276 
277  /* disable cutting plane separation */
279 
280  /* disable expensive presolving */
282 
283  /* use best estimate node selection */
284  if( SCIPfindNodesel(subscip, "estimate") != NULL && !SCIPisParamFixed(subscip, "nodeselection/estimate/stdpriority") )
285  {
286  SCIP_CALL( SCIPsetIntParam(subscip, "nodeselection/estimate/stdpriority", INT_MAX/4) );
287  }
288 
289  /* activate uct node selection at the top of the tree */
290  if( heurdata->useuct && SCIPfindNodesel(subscip, "uct") != NULL && !SCIPisParamFixed(subscip, "nodeselection/uct/stdpriority") )
291  {
292  SCIP_CALL( SCIPsetIntParam(subscip, "nodeselection/uct/stdpriority", INT_MAX/2) );
293  }
294 
295  /* use inference branching */
296  if( SCIPfindBranchrule(subscip, "inference") != NULL && !SCIPisParamFixed(subscip, "branching/inference/priority") )
297  {
298  SCIP_CALL( SCIPsetIntParam(subscip, "branching/inference/priority", INT_MAX/4) );
299  }
300 
301  /* enable conflict analysis, disable analysis of boundexceeding LPs, and restrict conflict pool */
302  if( !SCIPisParamFixed(subscip, "conflict/enable") )
303  {
304  SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/enable", TRUE) );
305  }
306  if( !SCIPisParamFixed(subscip, "conflict/useboundlp") )
307  {
308  SCIP_CALL( SCIPsetCharParam(subscip, "conflict/useboundlp", 'o') );
309  }
310  if( !SCIPisParamFixed(subscip, "conflict/maxstoresize") )
311  {
312  SCIP_CALL( SCIPsetIntParam(subscip, "conflict/maxstoresize", 100) );
313  }
314 
315  /* speed up sub-SCIP by not checking dual LP feasibility */
316  SCIP_CALL( SCIPsetBoolParam(subscip, "lp/checkdualfeas", FALSE) );
317 
318  /* add an objective cutoff */
319  assert( !SCIPisInfinity(scip,SCIPgetUpperbound(scip)) );
320 
321  upperbound = SCIPgetUpperbound(scip) - SCIPsumepsilon(scip);
322  if( !SCIPisInfinity(scip, -1.0 * SCIPgetLowerbound(scip)) )
323  {
324  cutoff = (1 - heurdata->minimprove) * SCIPgetUpperbound(scip) + heurdata->minimprove * SCIPgetLowerbound(scip);
325  }
326  else
327  {
328  if( SCIPgetUpperbound(scip) >= 0 )
329  cutoff = (1 - heurdata->minimprove) * SCIPgetUpperbound(scip);
330  else
331  cutoff = (1 + heurdata->minimprove) * SCIPgetUpperbound(scip);
332  }
333  cutoff = MIN(upperbound, cutoff);
334  SCIP_CALL( SCIPsetObjlimit(subscip, cutoff) );
335 
336  /* catch LP events of sub-SCIP */
337  SCIP_CALL( SCIPtransformProb(subscip) );
338  SCIP_CALL( SCIPcatchEvent(subscip, SCIP_EVENTTYPE_LPSOLVED, eventhdlr, (SCIP_EVENTDATA*) heurdata, NULL) );
339 
340  /* Errors in solving the subproblem should not kill the overall solving process
341  * Hence, the return code is caught and a warning is printed, only in debug mode, SCIP will stop.
342  */
343  /* solve the subproblem */
344  SCIP_CALL_ABORT( SCIPsolve(subscip) );
345 
346  /* drop LP events of sub-SCIP */
347  SCIP_CALL( SCIPdropEvent(subscip, SCIP_EVENTTYPE_LPSOLVED, eventhdlr, (SCIP_EVENTDATA*) heurdata, -1) );
348 
349  /* we try to merge variable statistics with those of our main SCIP */
350  SCIP_CALL( SCIPmergeVariableStatistics(subscip, scip, subvars, vars, nvars) );
351 
352  /* print solving statistics of subproblem if we are in SCIP's debug mode */
354 
355  heurdata->usednodes += SCIPgetNNodes(subscip);
356 
357  SCIP_CALL( SCIPtranslateSubSols(scip, subscip, heur, subvars, &success, NULL) );
358  if( success )
359  *result = SCIP_FOUNDSOL;
360 
361  /* free subproblem */
362  SCIPfreeBufferArray(scip, &subvars);
363 
364  return SCIP_OKAY;
365 }
366 
367 /* ---------------- Callback methods of event handler ---------------- */
368 
369 /* exec the event handler
370  *
371  * we interrupt the solution process
372  */
373 static
374 SCIP_DECL_EVENTEXEC(eventExecRins)
375 {
376  SCIP_HEURDATA* heurdata;
377 
378  assert(eventhdlr != NULL);
379  assert(eventdata != NULL);
380  assert(strcmp(SCIPeventhdlrGetName(eventhdlr), EVENTHDLR_NAME) == 0);
381  assert(event != NULL);
382  assert(SCIPeventGetType(event) & SCIP_EVENTTYPE_LPSOLVED);
383 
384  heurdata = (SCIP_HEURDATA*)eventdata;
385  assert(heurdata != NULL);
386 
387  /* interrupt solution process of sub-SCIP */
388  if( SCIPgetNLPs(scip) > heurdata->lplimfac * heurdata->nodelimit )
389  {
390  SCIPdebugMsg(scip, "interrupt after %" SCIP_LONGINT_FORMAT " LPs\n",SCIPgetNLPs(scip));
392  }
393 
394  return SCIP_OKAY;
395 }
396 
397 
398 /*
399  * Callback methods of primal heuristic
400  */
401 
402 /** copy method for primal heuristic plugins (called when SCIP copies plugins) */
403 static
404 SCIP_DECL_HEURCOPY(heurCopyRins)
405 { /*lint --e{715}*/
406  assert(scip != NULL);
407  assert(heur != NULL);
408  assert(strcmp(SCIPheurGetName(heur), HEUR_NAME) == 0);
409 
410  /* call inclusion method of primal heuristic */
412 
413  return SCIP_OKAY;
414 }
415 
416 /** destructor of primal heuristic to free user data (called when SCIP is exiting) */
417 static
418 SCIP_DECL_HEURFREE(heurFreeRins)
419 { /*lint --e{715}*/
420  SCIP_HEURDATA* heurdata;
421 
422  assert( heur != NULL );
423  assert( scip != NULL );
424 
425  /* get heuristic data */
426  heurdata = SCIPheurGetData(heur);
427  assert( heurdata != NULL );
428 
429  /* free heuristic data */
430  SCIPfreeBlockMemory(scip, &heurdata);
431  SCIPheurSetData(heur, NULL);
432 
433  return SCIP_OKAY;
434 }
435 
436 
437 /** initialization method of primal heuristic (called after problem was transformed) */
438 static
439 SCIP_DECL_HEURINIT(heurInitRins)
440 { /*lint --e{715}*/
441  SCIP_HEURDATA* heurdata;
442 
443  assert( heur != NULL );
444  assert( scip != NULL );
445 
446  /* get heuristic's data */
447  heurdata = SCIPheurGetData(heur);
448  assert( heurdata != NULL );
449 
450  /* initialize data */
451  heurdata->usednodes = 0;
452 
453  return SCIP_OKAY;
454 }
455 
456 
457 /** execution method of primal heuristic */
458 static
459 SCIP_DECL_HEUREXEC(heurExecRins)
460 { /*lint --e{715}*/
462 
463  SCIP_HEURDATA* heurdata; /* heuristic's data */
464  SCIP* subscip; /* the subproblem created by RINS */
465  SCIP_VAR** vars; /* original problem's variables */
466  SCIP_VAR** fixedvars;
467  SCIP_Real* fixedvals;
468 
469  SCIP_RETCODE retcode; /* retcode needed for wrapper method */
470 
471  int nvars;
472  int nbinvars;
473  int nintvars;
474  int nfixedvars;
475 
476  SCIP_Bool success;
477 
478  assert( heur != NULL );
479  assert( scip != NULL );
480  assert( result != NULL );
481  assert( SCIPhasCurrentNodeLP(scip) );
482 
483  *result = SCIP_DELAYED;
484 
485  /* do not call heuristic of node was already detected to be infeasible */
486  if( nodeinfeasible )
487  return SCIP_OKAY;
488 
489  /* get heuristic's data */
490  heurdata = SCIPheurGetData(heur);
491  assert( heurdata != NULL );
492 
493  /* only call heuristic, if an optimal LP solution and a feasible solution are at hand */
495  return SCIP_OKAY;
496 
497  /* only call heuristic, if the LP objective value is smaller than the cutoff bound */
499  return SCIP_OKAY;
500 
501  /* only call heuristic, if the best solution comes from transformed problem */
502  assert( SCIPgetBestSol(scip) != NULL );
504  return SCIP_OKAY;
505 
506  /* only call heuristic, if enough nodes were processed since last incumbent */
507  if( SCIPgetNNodes(scip) - SCIPgetSolNodenum(scip,SCIPgetBestSol(scip)) < heurdata->nwaitingnodes)
508  return SCIP_OKAY;
509 
510  *result = SCIP_DIDNOTRUN;
511 
512  /* calculate the maximal number of branching nodes until heuristic is aborted */
513  nnodes = (SCIP_Longint)(heurdata->nodesquot * SCIPgetNNodes(scip));
514 
515  /* reward RINS if it succeeded often */
516  nnodes = (SCIP_Longint)(nnodes * (SCIPheurGetNBestSolsFound(heur)+1.0)/(SCIPheurGetNCalls(heur) + 1.0));
517  nnodes -= (SCIP_Longint)(100.0 * SCIPheurGetNCalls(heur)); /* count the setup costs for the sub-MIP as 100 nodes */
518  nnodes += heurdata->nodesofs;
519 
520  /* determine the node limit for the current process */
521  nnodes -= heurdata->usednodes;
522  nnodes = MIN(nnodes, heurdata->maxnodes);
523 
524  /* check whether we have enough nodes left to call subproblem solving */
525  if( nnodes < heurdata->minnodes )
526  return SCIP_OKAY;
527 
528  SCIP_CALL( SCIPgetVarsData(scip, &vars, &nvars, &nbinvars, &nintvars, NULL, NULL) );
529 
530  /* check whether discrete variables are available */
531  if( nbinvars == 0 && nintvars == 0 )
532  return SCIP_OKAY;
533 
534  if( SCIPisStopped(scip) )
535  return SCIP_OKAY;
536 
537  /* allocate buffer storage to hold the RINS fixings */
538  SCIP_CALL( SCIPallocBufferArray(scip, &fixedvars, nbinvars + nintvars) );
539  SCIP_CALL( SCIPallocBufferArray(scip, &fixedvals, nbinvars + nintvars) );
540 
541  success = FALSE;
542 
543  nfixedvars = 0;
544  /* determine possible fixings for RINS: variables with same value in bestsol and LP relaxation */
545  SCIP_CALL( determineFixings(scip, fixedvars, fixedvals, &nfixedvars, nbinvars + nintvars, heurdata->minfixingrate, &success) );
546 
547  /* too few variables could be fixed by the RINS scheme */
548  if( !success )
549  goto TERMINATE;
550 
551  /* check whether there is enough time and memory left */
552  SCIP_CALL( SCIPcheckCopyLimits(scip, &success) );
553 
554  /* abort if no time is left or not enough memory to create a copy of SCIP */
555  if( !success )
556  goto TERMINATE;
557 
558  assert(nfixedvars > 0 && nfixedvars < nbinvars + nintvars);
559 
560  *result = SCIP_DIDNOTFIND;
561 
562  SCIPdebugMsg(scip, "RINS heuristic fixes %d out of %d binary+integer variables\n", nfixedvars, nbinvars + nintvars);
563  SCIP_CALL( SCIPcreate(&subscip) );
564 
565  retcode = wrapperRins(scip, subscip, heur, heurdata, vars, fixedvars, fixedvals, result, nvars, nfixedvars, nnodes);
566 
567  SCIP_CALL( SCIPfree(&subscip) );
568 
569  SCIP_CALL( retcode );
570 
571 TERMINATE:
572  SCIPfreeBufferArray(scip, &fixedvals);
573  SCIPfreeBufferArray(scip, &fixedvars);
574 
575  return SCIP_OKAY;
576 }
577 
578 /*
579  * primal heuristic specific interface methods
580  */
581 
582 /** creates the RINS primal heuristic and includes it in SCIP */
584  SCIP* scip /**< SCIP data structure */
585  )
586 {
587  SCIP_HEURDATA* heurdata;
588  SCIP_HEUR* heur;
589 
590  /* create Rins primal heuristic data */
591  SCIP_CALL( SCIPallocBlockMemory(scip, &heurdata) );
592 
593  /* include primal heuristic */
594  SCIP_CALL( SCIPincludeHeurBasic(scip, &heur,
596  HEUR_MAXDEPTH, HEUR_TIMING, HEUR_USESSUBSCIP, heurExecRins, heurdata) );
597 
598  assert(heur != NULL);
599 
600  /* set non-NULL pointers to callback methods */
601  SCIP_CALL( SCIPsetHeurCopy(scip, heur, heurCopyRins) );
602  SCIP_CALL( SCIPsetHeurFree(scip, heur, heurFreeRins) );
603  SCIP_CALL( SCIPsetHeurInit(scip, heur, heurInitRins) );
604 
605  /* add RINS primal heuristic parameters */
606  SCIP_CALL( SCIPaddIntParam(scip, "heuristics/" HEUR_NAME "/nodesofs",
607  "number of nodes added to the contingent of the total nodes",
608  &heurdata->nodesofs, FALSE, DEFAULT_NODESOFS, 0, INT_MAX, NULL, NULL) );
609 
610  SCIP_CALL( SCIPaddIntParam(scip, "heuristics/" HEUR_NAME "/maxnodes",
611  "maximum number of nodes to regard in the subproblem",
612  &heurdata->maxnodes, TRUE, DEFAULT_MAXNODES, 0, INT_MAX, NULL, NULL) );
613 
614  SCIP_CALL( SCIPaddIntParam(scip, "heuristics/" HEUR_NAME "/minnodes",
615  "minimum number of nodes required to start the subproblem",
616  &heurdata->minnodes, TRUE, DEFAULT_MINNODES, 0, INT_MAX, NULL, NULL) );
617 
618  SCIP_CALL( SCIPaddRealParam(scip, "heuristics/" HEUR_NAME "/nodesquot",
619  "contingent of sub problem nodes in relation to the number of nodes of the original problem",
620  &heurdata->nodesquot, FALSE, DEFAULT_NODESQUOT, 0.0, 1.0, NULL, NULL) );
621 
622  SCIP_CALL( SCIPaddIntParam(scip, "heuristics/" HEUR_NAME "/nwaitingnodes",
623  "number of nodes without incumbent change that heuristic should wait",
624  &heurdata->nwaitingnodes, TRUE, DEFAULT_NWAITINGNODES, 0, INT_MAX, NULL, NULL) );
625 
626  SCIP_CALL( SCIPaddRealParam(scip, "heuristics/" HEUR_NAME "/minimprove",
627  "factor by which " HEUR_NAME " should at least improve the incumbent",
628  &heurdata->minimprove, TRUE, DEFAULT_MINIMPROVE, 0.0, 1.0, NULL, NULL) );
629 
630  SCIP_CALL( SCIPaddRealParam(scip, "heuristics/" HEUR_NAME "/minfixingrate",
631  "minimum percentage of integer variables that have to be fixed",
632  &heurdata->minfixingrate, FALSE, DEFAULT_MINFIXINGRATE, 0.0, 1.0, NULL, NULL) );
633 
634  SCIP_CALL( SCIPaddRealParam(scip, "heuristics/" HEUR_NAME "/lplimfac",
635  "factor by which the limit on the number of LP depends on the node limit",
636  &heurdata->lplimfac, TRUE, DEFAULT_LPLIMFAC, 1.0, SCIP_REAL_MAX, NULL, NULL) );
637 
638  SCIP_CALL( SCIPaddBoolParam(scip, "heuristics/" HEUR_NAME "/uselprows",
639  "should subproblem be created out of the rows in the LP rows?",
640  &heurdata->uselprows, TRUE, DEFAULT_USELPROWS, NULL, NULL) );
641 
642  SCIP_CALL( SCIPaddBoolParam(scip, "heuristics/" HEUR_NAME "/copycuts",
643  "if uselprows == FALSE, should all active cuts from cutpool be copied to constraints in subproblem?",
644  &heurdata->copycuts, TRUE, DEFAULT_COPYCUTS, NULL, NULL) );
645 
646  SCIP_CALL( SCIPaddBoolParam(scip, "heuristics/" HEUR_NAME "/useuct",
647  "should uct node selection be used at the beginning of the search?",
648  &heurdata->useuct, TRUE, DEFAULT_USEUCT, NULL, NULL) );
649 
650  return SCIP_OKAY;
651 }
enum SCIP_Result SCIP_RESULT
Definition: type_result.h:61
SCIP_Bool SCIPsolIsOriginal(SCIP_SOL *sol)
Definition: sol.c:2721
#define SCIP_EVENTTYPE_LPSOLVED
Definition: type_event.h:101
SCIP_RETCODE SCIPsetSeparating(SCIP *scip, SCIP_PARAMSETTING paramsetting, SCIP_Bool quiet)
Definition: scip_param.c:979
#define NULL
Definition: def.h:267
SCIP_Bool SCIPisFeasEQ(SCIP *scip, SCIP_Real val1, SCIP_Real val2)
public methods for SCIP parameter handling
static SCIP_DECL_HEUREXEC(heurExecRins)
Definition: heur_rins.c:459
public methods for node selector plugins
public methods for memory management
SCIP_Real SCIPgetCutoffbound(SCIP *scip)
#define HEUR_PRIORITY
Definition: heur_rins.c:63
SCIP_Longint SCIPheurGetNBestSolsFound(SCIP_HEUR *heur)
Definition: heur.c:1599
SCIP_Bool SCIPisGE(SCIP *scip, SCIP_Real val1, SCIP_Real val2)
#define DEFAULT_MINNODES
Definition: heur_rins.c:72
public solving methods
SCIP_RETCODE SCIPincludeEventhdlrBasic(SCIP *scip, SCIP_EVENTHDLR **eventhdlrptr, const char *name, const char *desc, SCIP_DECL_EVENTEXEC((*eventexec)), SCIP_EVENTHDLRDATA *eventhdlrdata)
Definition: scip_event.c:104
SCIP_RETCODE SCIPgetVarsData(SCIP *scip, SCIP_VAR ***vars, int *nvars, int *nbinvars, int *nintvars, int *nimplvars, int *ncontvars)
Definition: scip_prob.c:1866
#define FALSE
Definition: def.h:94
SCIP_RETCODE SCIPhashmapCreate(SCIP_HASHMAP **hashmap, BMS_BLKMEM *blkmem, int mapsize)
Definition: misc.c:3074
const char * SCIPeventhdlrGetName(SCIP_EVENTHDLR *eventhdlr)
Definition: event.c:324
SCIP_RETCODE SCIPcopyLimits(SCIP *sourcescip, SCIP *targetscip)
Definition: scip_copy.c:3296
#define TRUE
Definition: def.h:93
#define SCIPdebug(x)
Definition: pub_message.h:93
enum SCIP_Retcode SCIP_RETCODE
Definition: type_retcode.h:63
methods commonly used by primal heuristics
SCIP_RETCODE SCIPsetPresolving(SCIP *scip, SCIP_PARAMSETTING paramsetting, SCIP_Bool quiet)
Definition: scip_param.c:953
SCIP_BRANCHRULE * SCIPfindBranchrule(SCIP *scip, const char *name)
Definition: scip_branch.c:297
struct SCIP_HeurData SCIP_HEURDATA
Definition: type_heur.h:77
public methods for problem variables
#define HEUR_FREQ
Definition: heur_rins.c:64
#define SCIPfreeBlockMemory(scip, ptr)
Definition: scip_mem.h:108
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 SCIPtranslateSubSols(SCIP *scip, SCIP *subscip, SCIP_HEUR *heur, SCIP_VAR **subvars, SCIP_Bool *success, int *solindex)
Definition: scip_copy.c:1448
#define EVENTHDLR_NAME
Definition: heur_rins.c:86
void * SCIPhashmapGetImage(SCIP_HASHMAP *hashmap, void *origin)
Definition: misc.c:3261
#define SCIPfreeBufferArray(scip, ptr)
Definition: scip_mem.h:136
SCIP_RETCODE SCIPcreate(SCIP **scip)
Definition: scip_general.c:307
void SCIPheurSetData(SCIP_HEUR *heur, SCIP_HEURDATA *heurdata)
Definition: heur.c:1374
#define SCIPallocBlockMemory(scip, ptr)
Definition: scip_mem.h:89
#define SCIPdebugMsg
Definition: scip_message.h:78
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 SCIPprintStatistics(SCIP *scip, FILE *file)
public methods for numerical tolerances
public methods for querying solving statistics
#define DEFAULT_MINIMPROVE
Definition: heur_rins.c:73
SCIP_RETCODE SCIPsolve(SCIP *scip)
Definition: scip_solve.c:2488
const char * SCIPheurGetName(SCIP_HEUR *heur)
Definition: heur.c:1453
#define SCIPerrorMessage
Definition: pub_message.h:64
SCIP_Bool SCIPisParamFixed(SCIP *scip, const char *name)
Definition: scip_param.c:219
SCIP_RETCODE SCIPsetHeurFree(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEURFREE((*heurfree)))
Definition: scip_heur.c:178
#define HEUR_USESSUBSCIP
Definition: heur_rins.c:68
#define DEFAULT_USELPROWS
Definition: heur_rins.c:78
public methods for event handler plugins and event handlers
SCIP_RETCODE SCIPsetBoolParam(SCIP *scip, const char *name, SCIP_Bool value)
Definition: scip_param.c:429
BMS_BLKMEM * SCIPblkmem(SCIP *scip)
Definition: scip_mem.c:57
struct SCIP_EventData SCIP_EVENTDATA
Definition: type_event.h:173
#define DEFAULT_MAXNODES
Definition: heur_rins.c:71
SCIP_RETCODE SCIPincludeHeurRins(SCIP *scip)
Definition: heur_rins.c:583
void SCIPhashmapFree(SCIP_HASHMAP **hashmap)
Definition: misc.c:3108
SCIP_RETCODE SCIPmergeVariableStatistics(SCIP *sourcescip, SCIP *targetscip, SCIP_VAR **sourcevars, SCIP_VAR **targetvars, int nvars)
Definition: scip_copy.c:1265
#define DEFAULT_USEUCT
Definition: heur_rins.c:83
SCIP_Real SCIPvarGetLPSol(SCIP_VAR *var)
Definition: var.c:18453
public methods for problem copies
public methods for primal CIP solutions
#define DEFAULT_LPLIMFAC
Definition: heur_rins.c:76
#define SCIP_CALL(x)
Definition: def.h:380
SCIP_Real SCIPgetLowerbound(SCIP *scip)
static SCIP_DECL_HEURCOPY(heurCopyRins)
Definition: heur_rins.c:404
SCIP_Longint SCIPheurGetNCalls(SCIP_HEUR *heur)
Definition: heur.c:1579
SCIP_Bool SCIPhasCurrentNodeLP(SCIP *scip)
Definition: scip_lp.c:83
public methods for primal heuristic plugins and divesets
public methods for constraint handler plugins and constraints
#define DEFAULT_MINFIXINGRATE
Definition: heur_rins.c:74
#define HEUR_TIMING
Definition: heur_rins.c:67
static SCIP_RETCODE determineFixings(SCIP *scip, SCIP_VAR **fixedvars, SCIP_Real *fixedvals, int *nfixedvars, int fixedvarssize, SCIP_Real minfixingrate, SCIP_Bool *success)
Definition: heur_rins.c:126
#define SCIPallocBufferArray(scip, ptr, num)
Definition: scip_mem.h:124
#define HEUR_MAXDEPTH
Definition: heur_rins.c:66
public data structures and miscellaneous methods
#define DEFAULT_NODESOFS
Definition: heur_rins.c:70
#define SCIP_Bool
Definition: def.h:91
SCIP_RETCODE SCIPcatchEvent(SCIP *scip, SCIP_EVENTTYPE eventtype, SCIP_EVENTHDLR *eventhdlr, SCIP_EVENTDATA *eventdata, int *filterpos)
Definition: scip_event.c:286
SCIP_LPSOLSTAT SCIPgetLPSolstat(SCIP *scip)
Definition: scip_lp.c:168
SCIP_EVENTTYPE SCIPeventGetType(SCIP_EVENT *event)
Definition: event.c:1030
#define HEUR_DESC
Definition: heur_rins.c:61
#define HEUR_NAME
Definition: heur_rins.c:60
#define DEFAULT_NWAITINGNODES
Definition: heur_rins.c:77
SCIP_RETCODE SCIPsetObjlimit(SCIP *scip, SCIP_Real objlimit)
Definition: scip_prob.c:1422
LNS heuristic that combines the incumbent with the LP optimum.
#define MIN(x, y)
Definition: def.h:243
SCIP_RETCODE SCIPsetIntParam(SCIP *scip, const char *name, int value)
Definition: scip_param.c:487
SCIP_RETCODE SCIPdropEvent(SCIP *scip, SCIP_EVENTTYPE eventtype, SCIP_EVENTHDLR *eventhdlr, SCIP_EVENTDATA *eventdata, int filterpos)
Definition: scip_event.c:320
int SCIPgetNSols(SCIP *scip)
Definition: scip_sol.c:2070
static SCIP_DECL_EVENTEXEC(eventExecRins)
Definition: heur_rins.c:374
SCIP_Bool SCIPisInfinity(SCIP *scip, SCIP_Real val)
static SCIP_DECL_HEURINIT(heurInitRins)
Definition: heur_rins.c:439
public methods for the LP relaxation, rows and columns
SCIP_RETCODE SCIPsetCharParam(SCIP *scip, const char *name, char value)
Definition: scip_param.c:661
#define SCIP_REAL_MAX
Definition: def.h:174
#define SCIP_LONGINT_FORMAT
Definition: def.h:165
public methods for branching rule plugins and branching
public methods for managing events
general public methods
#define MAX(x, y)
Definition: def.h:239
SCIP_Real SCIPgetLPObjval(SCIP *scip)
Definition: scip_lp.c:247
SCIP_SOL * SCIPgetBestSol(SCIP *scip)
Definition: scip_sol.c:2169
#define HEUR_DISPCHAR
Definition: heur_rins.c:62
public methods for solutions
public methods for message output
SCIP_RETCODE SCIPsetHeurInit(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEURINIT((*heurinit)))
Definition: scip_heur.c:194
SCIP_NODESEL * SCIPfindNodesel(SCIP *scip, const char *name)
Definition: scip_nodesel.c:234
SCIP_RETCODE SCIPcopyLargeNeighborhoodSearch(SCIP *sourcescip, SCIP *subscip, SCIP_HASHMAP *varmap, const char *suffix, SCIP_VAR **fixedvars, SCIP_Real *fixedvals, int nfixedvars, SCIP_Bool uselprows, SCIP_Bool copycuts, SCIP_Bool *success, SCIP_Bool *valid)
Definition: heuristics.c:951
#define SCIP_Real
Definition: def.h:173
#define HEUR_FREQOFS
Definition: heur_rins.c:65
SCIP_Bool SCIPisStopped(SCIP *scip)
Definition: scip_general.c:718
public methods for message handling
#define SCIP_Longint
Definition: def.h:158
SCIP_RETCODE SCIPcheckCopyLimits(SCIP *sourcescip, SCIP_Bool *success)
Definition: scip_copy.c:3253
SCIP_RETCODE SCIPtransformProb(SCIP *scip)
Definition: scip_solve.c:222
static SCIP_RETCODE wrapperRins(SCIP *scip, SCIP *subscip, SCIP_HEUR *heur, SCIP_HEURDATA *heurdata, SCIP_VAR **vars, SCIP_VAR **fixedvars, SCIP_Real *fixedvals, SCIP_RESULT *result, int nvars, int nfixedvars, SCIP_Longint nnodes)
Definition: heur_rins.c:206
SCIP_RETCODE SCIPsetHeurCopy(SCIP *scip, SCIP_HEUR *heur, SCIP_DECL_HEURCOPY((*heurcopy)))
Definition: scip_heur.c:162
#define nnodes
Definition: gastrans.c:74
SCIP_Real SCIPsumepsilon(SCIP *scip)
SCIP_RETCODE SCIPinterruptSolve(SCIP *scip)
Definition: scip_solve.c:3420
SCIP_Real SCIPgetUpperbound(SCIP *scip)
public methods for primal heuristics
#define SCIP_CALL_ABORT(x)
Definition: def.h:359
SCIP_HEURDATA * SCIPheurGetData(SCIP_HEUR *heur)
Definition: heur.c:1364
#define DEFAULT_COPYCUTS
Definition: heur_rins.c:80
SCIP_Longint SCIPgetNNodes(SCIP *scip)
SCIP_Longint SCIPgetNLPs(SCIP *scip)
public methods for global and local (sub)problems
static SCIP_DECL_HEURFREE(heurFreeRins)
Definition: heur_rins.c:418
SCIP_Real SCIPgetSolVal(SCIP *scip, SCIP_SOL *sol, SCIP_VAR *var)
Definition: scip_sol.c:1217
#define DEFAULT_NODESQUOT
Definition: heur_rins.c:75
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 SCIPsetSubscipsOff(SCIP *scip, SCIP_Bool quiet)
Definition: scip_param.c:904
SCIP_RETCODE SCIPsetLongintParam(SCIP *scip, const char *name, SCIP_Longint value)
Definition: scip_param.c:545
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
#define EVENTHDLR_DESC
Definition: heur_rins.c:87
SCIP_RETCODE SCIPfree(SCIP **scip)
Definition: scip_general.c:339
SCIP_Longint SCIPgetSolNodenum(SCIP *scip, SCIP_SOL *sol)
Definition: scip_sol.c:1513
memory allocation routines