cons_cumulative.c
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33 * - a set of jobs, represented by their integer start time variables \f$S_j\f$, their array of processing times \f$p_j\f$ and of
37 * The cumulative constraint ensures that for each point in time \f$t\f$ \f$\sum_{j: S_j \leq t < S_j + p_j} d_j \leq C\f$ holds.
51/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
71#define CONSHDLR_ENFOPRIORITY -2040000 /**< priority of the constraint handler for constraint enforcing */
72#define CONSHDLR_CHECKPRIORITY -3030000 /**< priority of the constraint handler for checking feasibility */
73#define CONSHDLR_SEPAFREQ 1 /**< frequency for separating cuts; zero means to separate only in the root node */
74#define CONSHDLR_PROPFREQ 1 /**< frequency for propagating domains; zero means only preprocessing propagation */
75#define CONSHDLR_EAGERFREQ 100 /**< frequency for using all instead of only the useful constraints in separation,
77#define CONSHDLR_MAXPREROUNDS -1 /**< maximal number of presolving rounds the constraint handler participates in (-1: no limit) */
78#define CONSHDLR_DELAYSEPA FALSE /**< should separation method be delayed, if other separators found cuts? */
79#define CONSHDLR_DELAYPROP FALSE /**< should propagation method be delayed, if other propagators found reductions? */
80#define CONSHDLR_NEEDSCONS TRUE /**< should the constraint handler be skipped, if no constraints are available? */
102#define DEFAULT_TTINFER TRUE /**< should time-table (core-times) propagator be used to infer bounds? */
105#define DEFAULT_USEADJUSTEDJOBS FALSE /**< should during edge-finding jobs be adusted which run on the border of the effective time horizon? */
106#define DEFAULT_TTEFCHECK TRUE /**< should time-table edge-finding be used to detect an overload? */
113#define DEFAULT_PRESOLPAIRWISE TRUE /**< should pairwise constraint comparison be performed in presolving? */
115#define DEFAULT_DETECTDISJUNCTIVE TRUE /**< search for conflict set via maximal cliques to detect disjunctive constraints */
116#define DEFAULT_DETECTVARBOUNDS TRUE /**< search for conflict set via maximal cliques to detect variable bound constraints */
117#define DEFAULT_MAXNODES 10000LL /**< number of branch-and-bound nodes to solve an independent cumulative constraint (-1: no limit) */
123#define DEFAULT_USEBDWIDENING TRUE /**< should bound widening be used during conflict analysis? */
178 unsigned int varbounds:1; /**< bool to store if variable bound strengthening was already preformed */
179 unsigned int triedsolving:1; /**< bool to store if we tried already to solve that constraint as independent subproblem */
192 SCIP_Bool cutsasconss; /**< should the cumulative constraint create cuts as knapsack constraints? */
196 SCIP_Bool useadjustedjobs; /**< should during edge-finding jobs be adusted which run on the border of the effective time horizon? */
209 SCIP_Bool detectdisjunctive; /**< search for conflict set via maximal cliques to detect disjunctive constraints */
210 SCIP_Bool detectvarbounds; /**< search for conflict set via maximal cliques to detect variable bound constraints */
212 SCIP_Bool presolpairwise; /**< should pairwise constraint comparison be performed in presolving? */
215 SCIP_Longint maxnodes; /**< number of branch-and-bound nodes to solve an independent cumulative constraint (-1: no limit) */
217 SCIP_DECL_SOLVECUMULATIVE((*solveCumulative)); /**< method to use a single cumulative condition */
221 SCIP_Longint nlbtimetable; /**< number of times the lower bound was tightened by the time-table propagator */
222 SCIP_Longint nubtimetable; /**< number of times the upper bound was tightened by the time-table propagator */
223 SCIP_Longint ncutofftimetable; /**< number of times the a cutoff was detected due to time-table propagator */
224 SCIP_Longint nlbedgefinder; /**< number of times the lower bound was tightened by the edge-finder propagator */
225 SCIP_Longint nubedgefinder; /**< number of times the upper bound was tightened by the edge-finder propagator */
226 SCIP_Longint ncutoffedgefinder; /**< number of times the a cutoff was detected due to edge-finder propagator */
227 SCIP_Longint ncutoffoverload; /**< number of times the a cutoff was detected due to overload checking via edge-finding */
228 SCIP_Longint nlbTTEF; /**< number of times the lower bound was tightened by time-table edge-finding */
229 SCIP_Longint nubTTEF; /**< number of times the upper bound was tightened by time-table edge-finding */
230 SCIP_Longint ncutoffoverloadTTEF;/**< number of times the a cutoff was detected due to overload checking via time-table edge-finding */
232 int nirrelevantjobs; /**< number of time a irrelevant/redundant jobs was removed form a constraint */
233 int nalwaysruns; /**< number of time a job removed form a constraint which run completely during the effective horizon */
237 int ndualbranchs; /**< number of times a dual branch was discoverd and applicable via probing */
238 int nallconsdualfixs; /**< number of times a dual fix was performed due to knowledge of all cumulative constraints */
248 * An inference information can be passed with each domain reduction to SCIP. This information is passed back to the
249 * constraint handler if the corresponding bound change has to be explained. It can be used to store information which
250 * help to construct a reason/explanation for a bound change. The inference information is limited to size of integer.
252 * In case of the cumulative constraint handler we store the used propagation algorithms for that particular bound
265};
344/** constructs an inference information out of a propagation rule, an earliest start and a latest completion time */
355 if( proprule == PROPRULE_0_INVALID || data1 < 0 || data1 >= (1<<15) || data2 < 0 || data2 >= (1<<15) )
401#define computeCoreWithInterval(begin, end, ect, lst) (MAX(0, MIN((end), (ect)) - MAX((lst), (begin))))
427 /* the code contains a bug; we need to check if an implication forces that the jobs do not run in parallel */
496 /* the code contains a bug; we need to check if an implication forces that the jobs do not run in parallel */
538/** collects all necessary binary variables to represent the jobs which can be active at time point of interest */
583 /* check the end time of this job is larger than the curtime; in this case the job is still running */
692 /* check the end time of this job is larger than the curtime; in this case the job is still running */
752 /* sort the arrays not-decreasing according to startsolvalues and endsolvalues (and sort the indices in the same way) */
791 /* sort the arrays not-decreasing according to startsolvalues and endsolvalues (and sort the indices in the same way) */
841 SCIPdebugMsg(scip, "%d: variable <%s>[%g,%g] (sol %g, duration %d) starttime %d, endtime = %d, demand = %d\n",
842 *nvars, SCIPvarGetName(var), SCIPvarGetLbLocal(var), SCIPvarGetUbLocal(var), SCIPgetSolVal(scip, sol, var),
861 SCIPdebugMsg(scip, "%d: variable <%s>[%g,%g] (sol %g, duration %d) starttime %d, endtime = %d, demand = %d\n",
862 *nvars, SCIPvarGetName(var), SCIPvarGetLbLocal(var), SCIPvarGetUbLocal(var), SCIPgetSolVal(scip, sol, var),
871 /* sort the arrays not-decreasing according to startsolvalues and endsolvalues (and sort the indices in the same way) */
906 SCIP_Real** cumulativedemands, /**< array to store the estimated cumulative demand for each point in time */
914 int* startindices; /* we will sort the startsolvalues, thus we need to know wich index of a job it corresponds to */
915 int* endindices; /* we will sort the endsolvalues, thus we need to know wich index of a job it corresponds to */
940 createSortedEventpoints(scip, nvars, vars, durations, starttimes, endtimes, startindices, endindices, TRUE);
1126 disjfactor2 = MAX( disjfactor2, (peak-(SCIP_Real)capacity)/peak * (nlarge/(SCIP_Real)ndemands) );
1127 cumfactor1 = MAX( cumfactor1, (peak-capacity)/peak * (capacity-deltademand)/(SCIP_Real)capacity );
1166 SCIPstatisticPrintf("cumulative constraint<%s>: DISJ1=%g, DISJ2=%g, CUM=%g, RS1 = %g, RS2 = %g, EST = %g\n",
1167 SCIPconsGetName(cons), consdata->disjfactor1, disjfactor2, cumfactor1, resstrength1, resstrength2,
1249 SCIP_Real* objvals, /**< array of objective coefficients for each job (linear objective function), or NULL if none */
1297 SCIP_CALL( SCIPcreateVarBasic(subscip, &subvars[v], name, ests[v], lsts[v], objval, SCIP_VARTYPE_INTEGER) );
1315 * @note This "meta" setting has to be set first since this call overwrite all parameters including for example the
1341 SCIPdebugMsg(subscip, "solved single cumulative condition with status %d\n", SCIPgetStatus(subscip));
1486 /* create for each job and time step a binary variable which is one if this jobs starts at this time point and a set
1527 SCIP_CALL( SCIPcreateVarBasic(subscip, &binvar, name, 0.0, 1.0, objval, SCIP_VARTYPE_BINARY) );
1530 /* add binary varibale to the set partitioning constraint which ensures that the job is started */
1541 /* adjusted the smallest earliest start time and the largest latest completion time with the effective horizon */
1548 /* create for each time a knapsack constraint which ensures that the resource capacity is not exceeded */
1557 SCIP_CALL( SCIPcreateConsBasicKnapsack(subscip, &cons, name, 0, NULL, NULL, (SCIP_Longint)capacity) );
1618 SCIPdebugMsg(scip, "solved single cumulative condition with status %d\n", SCIPgetStatus(subscip));
1684 /* check which binary varibale is the first binary varibale which is not globally fixed to zero */
1694 /* check which binary varibale is the last binary varibale which is not globally fixed to zero */
1749 * Method used to create and free the constraint handler data when including and removing the cumulative constraint
1914 SCIP_CONS** linkingconss, /**< array of linking constraints for the integer variables, or NULL */
1973 /* initialize variable lock data structure; the locks are only used if the constraint is a check constraint */
1978 SCIP_CALL( SCIPduplicateBlockMemoryArray(scip, &(*consdata)->linkingconss, linkingconss, nvars) );
1987 SCIP_CALL( SCIPgetTransformedVars(scip, (*consdata)->nvars, (*consdata)->vars, (*consdata)->vars) );
1989 /* multi-aggregated variables cannot be replaced by active variable; therefore we mark all variables for not
2000 SCIP_CALL( SCIPtransformConss(scip, (*consdata)->nvars, (*consdata)->linkingconss, (*consdata)->linkingconss) );
2162 SCIPinfoMessage(scip, file, ")[%d,%d) <= %d", consdata->hmin, consdata->hmax, consdata->capacity);
2187 SCIP_CALL( SCIPunlockVarCons(scip, consdata->vars[pos], cons, consdata->downlocks[pos], consdata->uplocks[pos]) );
2208 SCIPvarGetName(consdata->vars[pos]), SCIPvarGetLbGlobal(consdata->vars[pos]), SCIPvarGetUbGlobal(consdata->vars[pos]), SCIPconsGetName(cons));
2210 /* in case the we did not remove the variable in the last slot of the arrays we move the current last to this
2261 SCIPdebugMsg(scip, "linking constraint (%d of %d) for variable <%s>\n", v+1, nvars, SCIPvarGetName(var));
2284 assert(strcmp(SCIPconshdlrGetName(SCIPconsGetHdlr(consdata->linkingconss[v])), "linking") == 0 );
2299/** check for the given starting time variables with their demands and durations if the cumulative conditions for the
2307 SCIP_VAR** vars, /**< array of integer variable which corresponds to starting times for a job */
2320 int* startindices; /* we will sort the startsolvalues, thus we need to know which index of a job it corresponds to */
2321 int* endindices; /* we will sort the endsolvalues, thus we need to know which index of a job it corresponds to */
2343 /* compute time points where we have to check whether capacity constraint is infeasible or not */
2354 /* the constraint of the cumulative constraint handler should be called after the integrality check */
2359 /* we need to ensure that we check at least one time point during the effective horizon; therefore we project all
2369 /* sort the arrays not-decreasing according to start solution values and end solution values (and sort the
2457/** check if the given constrait is valid; checks each starting point of a job whether the remaining capacity is at
2510 SCIP_BDCHGIDX* bdchgidx, /**< the index of the bound change, representing the point of time where the change took place */
2513 SCIP_Bool* explanation /**< bool array which marks the variable which are part of the explanation if a cutoff was detected, or NULL */
2527 SCIPdebugMsg(scip, "variable <%s>: (demand %d) resolve propagation of core time algorithm (peak %d)\n",
2539 /* first we loop over all variables and adjust the capacity with those jobs which provide a global core at the
2540 * inference peak and those where the current conflict bounds provide a core at the inference peak
2554 /* compute cores of jobs; if core overlaps interval of inference variable add this job to the array */
2555 assert(!SCIPvarIsActive(var) || SCIPisFeasEQ(scip, SCIPgetVarUbAtIndex(scip, var, bdchgidx, TRUE), SCIPgetVarUbAtIndex(scip, var, bdchgidx, FALSE)));
2557 assert(!SCIPvarIsActive(var) || SCIPisFeasEQ(scip, SCIPgetVarLbAtIndex(scip, var, bdchgidx, TRUE), SCIPgetVarLbAtIndex(scip, var, bdchgidx, FALSE)));
2567 /* check if the inference peak is part of the global bound core; if so we decreasing the capacity by the demand of
2585 /* collect the conflict bound core (the conflict bounds are those bounds which are already part of the conflict)
2586 * hence these bound are already reported by other resolve propation steps. In case a bound (lower or upper) is
2592 /* check if the inference peak is part of the conflict bound core; if so we decreasing the capacity by the demand
2595 * @note we do not need to reported that job to SCIP since the required bounds are already reported
2622 /* collect all cores of the variables which lay in the considered time window except the inference variable */
2635 /* compute cores of jobs; if core overlaps interval of inference variable add this job to the array */
2636 assert(!SCIPvarIsActive(var) || SCIPisFeasEQ(scip, SCIPgetVarUbAtIndex(scip, var, bdchgidx, TRUE), SCIPgetVarUbAtIndex(scip, var, bdchgidx, FALSE)));
2638 assert(!SCIPvarIsActive(var) || SCIPisFeasEQ(scip, SCIPgetVarLbAtIndex(scip, var, bdchgidx, TRUE), SCIPgetVarLbAtIndex(scip, var, bdchgidx, FALSE)));
2646 SCIPvarGetName(var), SCIPgetVarLbAtIndex(scip, var, bdchgidx, FALSE), SCIPgetVarUbAtIndex(scip, var, bdchgidx, FALSE),
2690 SCIPdebugMsg(scip, "infer peak %d, relaxed peak %d, lst %d, ect %d\n", inferpeak, relaxedpeak, maxlst, minect);
2718 SCIP_CALL( SCIPaddConflictRelaxedLb(scip, var, bdchgidx, (SCIP_Real)(inferpeak - duration + 1)) );
2743/** compute the minimum overlaps w.r.t. the duration of the job and the time window [begin,end) */
2776/** an overload was detected due to the time-time edge-finding propagate; initialized conflict analysis, add an initial
2779 * @note the conflict analysis is not performend, only the initialized SCIP_Bool pointer is set to TRUE
2793 SCIP_BDCHGIDX* bdchgidx, /**< the index of the bound change, representing the point of time where the change took place */
2796 SCIP_Bool* explanation /**< bool array which marks the variable which are part of the explanation if a cutoff was detected, or NULL */
2813 SCIPdebugMsg(scip, "analysis energy load in [%d,%d) (capacity %d, energy %" SCIP_LONGINT_FORMAT ")\n", begin, end, capacity, requiredenergy);
2815 /* collect global contribution and adjusted the required energy by the amount of energy the inference variable
2850 SCIPvarGetName(var), SCIPgetVarLbAtIndex(scip, var, bdchgidx, FALSE), SCIPgetVarUbAtIndex(scip, var, bdchgidx, FALSE),
2853 /* compute the amount of energy which needs to be available for enforcing the propagation and report the bound
2860 /* get the latest start time of the infer start time variable before the propagation took place */
2863 /* the latest start time of the inference start time variable before the propagation needs to be smaller as
2864 * the end of the time interval; meaning the job needs be overlap with the time interval in case the job is
2869 /* compute the overlap of the job in case it would be scheduled w.r.t. its latest start time and the time
2874 /* the job needs to overlap with the interval; otherwise the propagation w.r.t. this time window is not valid */
2879 assert(bdchgidx == NULL || SCIPconvertRealToInt(scip, SCIPgetVarUbAtIndex(scip, var, bdchgidx, TRUE)) < begin);
2893 assert(SCIPconvertRealToInt(scip, SCIPgetVarUbAtIndex(scip, var, bdchgidx, FALSE)) <= (end - overlap));
2907 /* get the earliest completion time of the infer start time variable before the propagation took place */
2910 /* the earliest start time of the inference start time variable before the propagation needs to be larger as
2911 * than the beginning of the time interval; meaning the job needs be overlap with the time interval in case
2916 /* compute the overlap of the job in case it would be scheduled w.r.t. its earliest start time and the time
2921 /* the job needs to overlap with the interval; otherwise the propagation w.r.t. this time window is not valid */
2940 assert(SCIPconvertRealToInt(scip, SCIPgetVarLbAtIndex(scip, var, bdchgidx, FALSE)) >= (begin + overlap - duration));
2941 SCIP_CALL( SCIPaddConflictRelaxedLb(scip, var, bdchgidx, (SCIP_Real)(begin + overlap - duration)) );
2949 /* subtract the amount of energy which is available due to the overlap of the inference start time */
2964 /* check if the has any overlap w.r.t. global bound; meaning some parts of the job will run for sure within the
2983 /* check if the job has any overlap w.r.t. local bound; meaning some parts of the job will run for sure within the
3044 SCIPdebugMsg(scip, "variable <%s> glb=[%g,%g] loc=[%g,%g], conf=[%g,%g], added=[%d,%d] (demand %d, duration %d)\n",
3081 SCIP_BDCHGIDX* bdchgidx, /**< the index of the bound change, representing the point of time where the change took place */
3084 SCIP_Bool* explanation, /**< bool array which marks the variable which are part of the explanation if a cutoff was detected, or NULL */
3085 SCIP_RESULT* result /**< pointer to store the result of the propagation conflict resolving call */
3115 /* we propagated the latest start time (upper bound) step wise with a step length of at most the duration of
3118 assert(SCIPgetVarUbAtIndex(scip, infervar, bdchgidx, FALSE) - SCIPgetVarUbAtIndex(scip, infervar, bdchgidx, TRUE) < inferduration + 0.5);
3126 /* the bound passed back to be resolved might be tighter as the bound propagted by the core time propagator;
3127 * this can happen if the variable is not activ and aggregated to an activ variable with a scale != 1.0
3129 assert(SCIPconvertRealToInt(scip, SCIPgetVarUbAtIndex(scip, infervar, bdchgidx, TRUE)) + inferduration <= inferpeak);
3153 /* the bound passed back to be resolved might be tighter as the bound propagted by the core time propagator;
3154 * this can happen if the variable is not activ and aggregated to an activ variable with a scale != 1.0
3156 assert(SCIPconvertRealToInt(scip, SCIPgetVarLbAtIndex(scip, infervar, bdchgidx, TRUE)) - 1 >= inferpeak);
3171 SCIP_CALL( resolvePropagationCoretimes(scip, nvars, vars, durations, demands, capacity, hmin, hmax,
3172 infervar, inferdemand, inferpeak, relaxedpeak, bdchgidx, usebdwidening, &provedpeak, explanation) );
3192 SCIP_CALL( SCIPaddConflictRelaxedLb(scip, infervar, bdchgidx, (SCIP_Real)(provedpeak - inferduration + 1)) );
3270 if( SCIPvarGetNLocksDownType(var, SCIP_LOCKTYPE_MODEL) == downlocks[v] && !SCIPisNegative(scip, objval) )
3278 SCIP_CALL( SCIPbranchVarHole(scip, var, SCIPvarGetLbLocal(var), (SCIP_Real)alternativelbs[v], NULL, NULL) );
3288 if( SCIPvarGetNLocksUpType(var, SCIP_LOCKTYPE_MODEL) == uplocks[v] && !SCIPisPositive(scip, objval) )
3296 SCIP_CALL( SCIPbranchVarHole(scip, var, (SCIP_Real)alternativeubs[v], SCIPvarGetUbLocal(var), NULL, NULL) );
3381/** computes a point in time when the capacity is exceeded returns hmax if this does not happen */
3392 int* startindices; /* we will sort the startsolvalues, thus we need to know wich index of a job it corresponds to */
3393 int* endindices; /* we will sort the endsolvalues, thus we need to know wich index of a job it corresponds to */
3438 subtractStartingJobDemands(consdata, curtime, starttimes, startindices, &freecapacity, &j, nvars);
3466/** checks all cumulative constraints for infeasibility and add branching candidates to storage */
3643/** in case the cumulative constraint is independent of every else, solve the cumulative problem and apply the fixings
3650 SCIP_Longint maxnodes, /**< number of branch-and-bound nodes to solve an independent cumulative constraint (-1: no limit) */
3676 /* if SCIP is in probing mode or repropagation we cannot perform this dual reductions since this dual reduction
3682 /* constraints for which the check flag is set to FALSE, did not contribute to the lock numbers; therefore, we cannot
3690 /* if the cumulative constraint is the only constraint of the original problem or the only check constraint in the
3704 /* after 250 conflict we force a restart since then the variable statistics are reasonable initialized */
3740 /* check if already tried to solve that constraint as independent sub problem; we do not want to try it again if we
3750 /* mark the constraint to be tried of solving it as independent sub problem; in case that is successful the
3755 SCIPdebugMsg(scip, "the cumulative constraint <%s> is independent from rest of the problem (%d variables, %d constraints)\n",
3770 /* if a variables array is given, use the variable bounds otherwise the default values stored in the ests and lsts
3788 /* substract the memory already used by the main SCIP and the estimated memory usage of external software */
3796 SCIP_CALL( SCIPsolveCumulative(scip, nvars, lbs, ubs, objvals, consdata->durations, consdata->demands, consdata->capacity,
3797 consdata->hmin, consdata->hmax, timelimit, memorylimit, maxnodes, &solved, cutoff, unbounded, &error) );
3877 SCIP_Bool* explanation /**< bool array which marks the variable which are part of the explanation if a cutoff was detected, or NULL */
3880 SCIPdebugMsg(scip, "detected infeasibility due to adding a core to the core resource profile\n");
3881 SCIPdebugMsg(scip, "variable <%s>[%g,%g] (demand %d, duration %d)\n", SCIPvarGetName(infervar),
3889 SCIP_CALL( resolvePropagationCoretimes(scip, nvars, vars, durations, demands, capacity, hmin, hmax,
3894 /* add both bound of the inference variable since these biuld the core which we could not inserted */
3897 SCIP_CALL( SCIPaddConflictRelaxedLb(scip, infervar, NULL, (SCIP_Real)(inferpeak - inferduration + 1)) );
3912/** We are using the core resource profile which contains all core except the one of the start time variable which we
3913 * want to propagate, to incease the earliest start time. This we are doing in steps of length at most the duration of
3914 * the job. The reason for that is, that this makes it later easier to resolve this propagation during the conflict
3933 SCIP_Bool* explanation, /**< bool array which marks the variable which are part of the explanation if a cutoff was detected, or NULL */
3960 /* first we find left position of earliest start time (lower bound) in resource profile; this position gives us the
3986 /* we search for a peak within the core profile which conflicts with the demand of the start time variable; we
3999 /* if we found no peak that means current the job could be scheduled at its earliest start time without
4006 /* the peak position gives us a time point where the start time variable is in conflict with the resource
4007 * profile. That means we have to move it to the next time point in the resource profile but at most to the
4019 SCIP_CALL( analyseInfeasibelCoreInsertion(scip, nvars, vars, durations, demands, capacity, hmin, hmax,
4030 /* construct the inference information which we are using with the conflict analysis to resolve that particular
4038 SCIP_CALL( SCIPinferVarLbCons(scip, var, (SCIP_Real)newlb, cons, inferInfoToInt(inferinfo), TRUE, infeasible, &tightened) );
4047 SCIPdebugMsg(scip, "variable <%s> new lower bound <%d> -> <%d>\n", SCIPvarGetName(var), est, newlb);
4050 /* for the statistic we count the number of times a lower bound was tightened due the the time-table algorithm */
4055 * @note We are taking the lower of the start time variable on purpose instead of newlb. This is due the fact that
4056 * the proposed lower bound might be even strength by be the core which can be the case if aggregations are
4073/** We are using the core resource profile which contains all core except the one of the start time variable which we
4074 * want to propagate, to decrease the latest start time. This we are doing in steps of length at most the duration of
4075 * the job. The reason for that is, that this makes it later easier to resolve this propagation during the conflict
4114 /* first we find left position of latest completion time minus 1 (upper bound + duration) in resource profile; That
4115 * is the last time point where the job would run if schedule it at its latest start time (upper bound). This
4145 /* we search for a peak within the core profile which conflicts with the demand of the start time variable; we
4157 /* if we found no peak that means the current job could be scheduled at its latest start time without conflicting
4164 /* the peak position gives us a time point where the start time variable is in conflict with the resource
4165 * profile. That means the job has be done until that point. Hence that gives us the latest completion
4166 * time. Note that that we want to move the bound by at most the duration length (the remaining move we are
4173 /* construct the inference information which we are using with the conflict analysis to resolve that particular
4181 SCIP_CALL( SCIPinferVarUbCons(scip, var, (SCIP_Real)newub, cons, inferInfoToInt(inferinfo), TRUE, &infeasible, &tightened) );
4190 SCIPdebugMsg(scip, "variable <%s>: new upper bound <%d> -> <%d>\n", SCIPvarGetName(var), lst, newub);
4193 /* for the statistic we count the number of times a upper bound was tightened due the the time-table algorithm */
4198 * @note We are taking the upper of the start time variable on purpose instead of newub. This is due the fact that
4199 * the proposed upper bound might be even strength by be the core which can be the case if aggregations are
4217/** compute for the different earliest start and latest completion time the core energy of the corresponding time
4226 int* coreEnergyAfterEst, /**< array to store the core energy after the earliest start time of each job */
4227 int* coreEnergyAfterLct /**< array to store the core energy after the latest completion time of each job */
4246 energy += SCIPprofileGetLoad(profile, t-1) * (SCIPprofileGetTime(profile, t) - SCIPprofileGetTime(profile, t-1));
4255 coreEnergyAfterEst[v] = energy + SCIPprofileGetLoad(profile, t-1) * (SCIPprofileGetTime(profile, t) - ests[v]);
4271 energy += SCIPprofileGetLoad(profile, t-1) * (SCIPprofileGetTime(profile, t) - SCIPprofileGetTime(profile, t-1));
4280 coreEnergyAfterLct[v] = energy + SCIPprofileGetLoad(profile, t-1) * (SCIPprofileGetTime(profile, t) - lcts[v]);
4375 SCIP_Longint energy, /**< available energy for the flexible part of the hob within the time window */
4377 int* inferinfos, /**< pointer to store the inference information which is need for the (best) lower bound change */
4379 SCIP_Bool* explanation, /**< bool array which marks the variable which are part of the explanation if a cutoff was detected, or NULL */
4392 /* if the job can be processed completely before or after the time window, nothing can be tightened */
4396 /* if flexible part runs completely within the time window (assuming it is scheduled on its earliest start time), we
4402 /* check if the available energy in the time window is to small to handle the flexible part if it is schedule on its
4408 /* adjust the available energy for the job; the given available energy assumes that the core of the considered job is
4411 * @note the variable ect define the earliest completion time of the flexible part of the job; hence we need to
4416 /* compute a latest start time (upper bound) such that the job consums at most the available energy
4422 /* check if we detected an infeasibility which is the case if the new lower bound is larger than the current upper
4445 begin, end, var, SCIP_BOUNDTYPE_LOWER, NULL, relaxedbd, conshdlrdata->usebdwidening, explanation) );
4488 SCIP_Longint energy, /**< available energy for the flexible part of the hob within the time window */
4490 int* inferinfos, /**< pointer to store the inference information which is need for the (best) upper bound change */
4492 SCIP_Bool* explanation, /**< bool array which marks the variable which are part of the explanation if a cutoff was detected, or NULL */
4506 /* if flexible part of the job can be processed completely before or after the time window, nothing can be tightened */
4510 /* if flexible part runs completely within the time window (assuming it is scheduled on its latest start time), we
4516 /* check if the available energy in the time window is to small to handle the flexible part of the job */
4520 /* adjust the available energy for the job; the given available energy assumes that the core of the considered job is
4523 * @note the variable lst define the latest start time of the flexible part of the job; hence we need to compute the
4529 /* compute a latest start time (upper bound) such that the job consums at most the available energy
4536 /* check if we detected an infeasibility which is the case if the new upper bound is smaller than the current lower
4559 begin, end, var, SCIP_BOUNDTYPE_UPPER, NULL, relaxedbd, conshdlrdata->usebdwidening, explanation) );
4582/** propagate the upper bounds and "opportunistically" the lower bounds using the time-table edge-finding algorithm */
4596 int* lbinferinfos, /**< array to store the inference information for the lower bound changes */
4597 int* ubinferinfos, /**< array to store the inference information for the upper bound changes */
4598 int* lsts, /**< array of latest start time of the flexible part in the same order as the variables */
4600 int* perm, /**< permutation of the variables w.r.t. the non-decreasing order of the earliest start times */
4606 SCIP_Bool* explanation, /**< bool array which marks the variable which are part of the explanation if a cutoff was detected, or NULL */
4645 /* check if the smallest interval has a size such that the total energy fits, if so we can skip the propagator */
4651 /* loop over all variable in non-increasing order w.r.t. the latest completion time; thereby, the latest completion
4664 /* if the latest completion time is larger then hmax an infeasibility cannot be detected, since after hmax an
4677 /* if the latest completion time equals to previous end time, we can continue since this particular interval
4685 /* In case we only want to detect an overload (meaning no bound propagation) we can skip the interval; this is
4686 * the case if the free energy (the energy which is not occupied by any core) is smaller than the previous minimum
4697 freeenergy = capacity * ((SCIP_Longint) end - lct) - coreEnergyAfterLct[v] + coreEnergyAfterEnd;
4701 SCIPdebugMsg(scip, "skip latest completion time <%d> (minimum available energy <%" SCIP_LONGINT_FORMAT ">, free energy <%" SCIP_LONGINT_FORMAT ">)\n", lct, minavailable, freeenergy);
4717 /* loop over the job in non-increasing order w.r.t. the earliest start time; these earliest start time are
4718 * defining the beginning of the time interval under investigation; Thereby, the time interval gets wider and
4739 /* if the job starts after the current end, we can skip it and do not need to consider it again since the
4748 /* check if the interval has a size such that the total energy fits, if so we can skip all intervals with the
4768 /* in case the earliest start time is equal to minbegin, the job lies completely within the time window under
4777 SCIP_CALL( tightenUbTTEF(scip, conshdlrdata, nvars, vars, durations, demands, capacity, hmin, hmax,
4778 var, duration, demand, est, lst, lct, minbegin, end, minavailable, &(newubs[idx]), &(ubinferinfos[idx]),
4785 SCIPdebugMsg(scip, "check variable <%s>[%g,%g] (duration %d, demands %d, est <%d>, lst of free part <%d>\n",
4786 SCIPvarGetName(var), SCIPvarGetLbLocal(var), SCIPvarGetUbLocal(var), duration, demand, est, lst);
4791 /* if the earliest start time is smaller than hmin we can stop here since the next job will not decrease the
4811 /* compute the flexible energy which is part of the time interval for sure if the job is scheduled
4823 /* compute the flexible energy of the job which is not part of flexible energy of the time interval */
4839 freeenergy = capacity * ((SCIP_Longint) end - begin) - flexenergy - coreEnergyAfterEst[i] + coreEnergyAfterEnd;
4844 SCIPdebugMsg(scip, "analyze overload within time window [%d,%d) capacity %d\n", begin, end, capacity);
4861 /* for the statistic we count the number of times a cutoff was detected due the time-time-edge-finding */
4862 SCIPstatistic( SCIPconshdlrGetData(SCIPfindConshdlr(scip, CONSHDLR_NAME))->ncutoffoverloadTTEF++ );
4867 /* check if the available energy is not sufficent to schedule the flexible energy of the best candidate job */
4878 energy = freeenergy + (computeCoreWithInterval(begin, end, ect, lst) + MAX(0, (SCIP_Longint) end - lsts[lbcand])) * demands[lbcand];
4933/** propagate the lower bounds and "opportunistically" the upper bounds using the time-table edge-finding algorithm */
4947 int* lbinferinfos, /**< array to store the inference information for the lower bound changes */
4948 int* ubinferinfos, /**< array to store the inference information for the upper bound changes */
4949 int* ects, /**< array of earliest completion time of the flexible part in the same order as the variables */
4951 int* perm, /**< permutation of the variables w.r.t. the non-decreasing order of the latest completion times */
4957 SCIP_Bool* explanation, /**< bool array which marks the variable which are part of the explanation if a cutoff was detected, or NULL */
4998 /* check if the smallest interval has a size such that the total energy fits, if so we can skip the propagator */
5004 /* loop over all variable in non-decreasing order w.r.t. the earliest start times; thereby, the earliest start times
5018 /* if the earliest start time is smaller then hmin an infeasibility cannot be detected, since before hmin an
5028 /* if the latest earliest start time equals to previous start time, we can continue since this particular interval
5047 /* loop over the job in non-decreasing order w.r.t. the latest completion time; these latest completion times are
5048 * defining the ending of the time interval under investigation; thereby, the time interval gets wider and wider
5068 /* if the job has a latest completion time before the the current start, we can skip it and do not need to
5069 * consider it again since the earliest start times (which define the start) are scant in non-decreasing order
5077 /* check if the interval has a size such that the total energy fits, if so we can skip all intervals which
5097 /* in case the latest completion time is equal to minend, the job lies completely within the time window under
5106 SCIP_CALL( tightenLbTTEF(scip, conshdlrdata, nvars, vars, durations, demands, capacity, hmin, hmax,
5107 var, duration, demand, est, ect, lct, begin, minend, minavailable, &(newlbs[idx]), &(lbinferinfos[idx]),
5114 SCIPdebugMsg(scip, "check variable <%s>[%g,%g] (duration %d, demands %d, est <%d>, ect of free part <%d>\n",
5115 SCIPvarGetName(var), SCIPvarGetLbLocal(var), SCIPvarGetUbLocal(var), duration, demand, est, ect);
5120 /* if the latest completion time is larger than hmax we can stop here since the next job will not decrease the
5140 /* compute the flexible energy which is part of the time interval for sure if the job is scheduled
5152 /* compute the flexible energy of the job which is not part of flexible energy of the time interval */
5168 freeenergy = capacity * ((SCIP_Longint) end - begin) - flexenergy - coreEnergyAfterStart + coreEnergyAfterLct[i];
5173 SCIPdebugMsg(scip, "analyze overload within time window [%d,%d) capacity %d\n", begin, end, capacity);
5190 /* for the statistic we count the number of times a cutoff was detected due the time-time-edge-finding */
5191 SCIPstatistic( SCIPconshdlrGetData(SCIPfindConshdlr(scip, CONSHDLR_NAME))->ncutoffoverloadTTEF++ );
5196 /* check if the available energy is not sufficent to schedule the flexible energy of the best candidate job */
5210 energy = freeenergy + (computeCoreWithInterval(begin, end, ect, lst) + MAX(0, (SCIP_Longint) ects[ubcand] - begin)) * demands[ubcand];
5264/** checks whether the instance is infeasible due to a overload within a certain time frame using the idea of time-table
5268 * - Petr Vilim, "Timetable Edge Finding Filtering Algorithm for Discrete Cumulative Resources", In: Tobias
5269 * Achterberg and J. Christopher Beck (Eds.), Integration of AI and OR Techniques in Constraint Programming for
5271 * - Andreas Schutt, Thibaut Feydy, and Peter J. Stuckey, "Explaining Time-Table-Edge-Finding Propagation for the
5289 SCIP_Bool* explanation, /**< bool array which marks the variable which are part of the explanation if a cutoff was detected, or NULL */
5335 /* we need to buffer the bound changes since the propagation algorithm cannot handle new bound dynamically */
5345 collectDataTTEF(scip, nvars, vars, durations, demands, hmin, hmax, permests, ests, permlcts, lcts, ects, lsts, flexenergies);
5351 /* compute for the different earliest start and latest completion time the core energy of the corresponding time
5357 SCIP_CALL( propagateUbTTEF(scip, conshdlrdata, nvars, vars, durations, demands, capacity, hmin, hmax,
5359 permests, ests, lcts, coreEnergyAfterEst, coreEnergyAfterLct, initialized, explanation, cutoff) );
5362 SCIP_CALL( propagateLbTTEF(scip, conshdlrdata, nvars, vars, durations, demands, capacity, hmin, hmax,
5364 permlcts, ests, lcts, coreEnergyAfterEst, coreEnergyAfterLct, initialized, explanation, cutoff) );
5379 SCIP_CALL( SCIPtightenVarLb(scip, vars[v], (SCIP_Real)newlbs[v], TRUE, &infeasible, &tightened) );
5382 /* since we change first the lower bound of the variable an infeasibilty should not be detected */
5400 SCIP_CALL( SCIPtightenVarUb(scip, vars[v], (SCIP_Real)newubs[v], TRUE, &infeasible, &tightened) );
5403 /* since upper bound was compute w.r.t. the "old" bound the previous lower bound update together with this upper
5408 /* a small performance improvement is possible here: if the tighten...TEFF and propagate...TEFF methods would
5409 * return not only the inferinfos, but the actual begin and end values, then the infeasibility here could also
5412 if( SCIPisConflictAnalysisApplicable(scip) && inferInfoIsValid(intToInferInfo(ubinferinfos[v])) )
5445 SCIPstatistic( SCIPconshdlrGetData(SCIPfindConshdlr(scip, CONSHDLR_NAME))->ncutoffoverloadTTEF++ );
5479/** a cumulative condition is not satisfied if its capacity is exceeded at a time where jobs cannot be shifted (core)
5480 * anymore we build up a cumulative profile of all cores of jobs and try to improve bounds of all jobs; also known as
5498 SCIP_Bool* explanation, /**< bool array which marks the variable which are part of the explanation if a cutoff was detected, or NULL */
5520 SCIPdebugMsg(scip, "propagate cores of cumulative condition of constraint <%s>[%d,%d) <= %d\n",