    001package org.cpsolver.ifs.solver;
    002
    003import java.util.ArrayList;
    004import java.util.Collection;
    005import java.util.HashMap;
    006import java.util.Iterator;
    007import java.util.List;
    008import java.util.Map;
    009import java.util.concurrent.ArrayBlockingQueue;
    010import java.util.concurrent.BlockingQueue;
    011import java.util.concurrent.TimeUnit;
    012import java.util.concurrent.locks.Lock;
    013
    014import org.cpsolver.ifs.assignment.Assignment;
    015import org.cpsolver.ifs.assignment.DefaultParallelAssignment;
    016import org.cpsolver.ifs.assignment.DefaultSingleAssignment;
    017import org.cpsolver.ifs.assignment.context.CanHoldContext;
    018import org.cpsolver.ifs.model.LazyNeighbour;
    019import org.cpsolver.ifs.model.LazyNeighbour.LazyNeighbourAcceptanceCriterion;
    020import org.cpsolver.ifs.model.Model;
    021import org.cpsolver.ifs.model.Neighbour;
    022import org.cpsolver.ifs.model.Value;
    023import org.cpsolver.ifs.model.Variable;
    024import org.cpsolver.ifs.solution.Solution;
    025import org.cpsolver.ifs.solution.SolutionListener;
    026import org.cpsolver.ifs.util.DataProperties;
    027import org.cpsolver.ifs.util.JProf;
    028import org.cpsolver.ifs.util.Progress;
    029import org.cpsolver.ifs.util.ToolBox;
    030
    031
    032/**
    033 * Multi-threaded solver. Instead of one, a given number of solver threads are created
    034 * (as defined by Parallel.NrSolvers property) and started in parallel. Each thread
    035 * works with its own assignment {@link DefaultParallelAssignment}, but the best solution
    036 * is shared among all of them.<br>
    037 * <br>
    038 * When {@link DefaultSingleAssignment} is given to the solver, only one solution is used.
    039 * A neighbour is assigned to this (shared) solution when it does not create any conflicts
    040 * outside of {@link Neighbour#assignments()}.
    041 *
    042 * @see Solver
    043 *
    044 * @version IFS 1.3 (Iterative Forward Search)<br>
    045 *          Copyright (C) 2014 Tomáš Müller<br>
    046 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    047 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    048 * <br>
    049 *          This library is free software; you can redistribute it and/or modify
    050 *          it under the terms of the GNU Lesser General Public License as
    051 *          published by the Free Software Foundation; either version 3 of the
    052 *          License, or (at your option) any later version. <br>
    053 * <br>
    054 *          This library is distributed in the hope that it will be useful, but
    055 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    056 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    057 *          Lesser General Public License for more details. <br>
    058 * <br>
    059 *          You should have received a copy of the GNU Lesser General Public
    060 *          License along with this library; if not see <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>.
    061 *
    062 * @param <V> Variable
    063 * @param <T> Value
    064 **/
    065public class ParallelSolver<V extends Variable<V, T>, T extends Value<V, T>> extends Solver<V, T> {
    066    private SynchronizationThread iSynchronizationThread = null;
    067    private int iNrFinished = 0;
    068
    069    public ParallelSolver(DataProperties properties) {
    070        super(properties);
    071    }
    072
    073    /** Starts solver */
    074    @Override
    075    public void start() {
    076        int nrSolvers = Math.min(Math.abs(getProperties().getPropertyInt("Parallel.NrSolvers", 4)), CanHoldContext.sMaxSize - 1);
    077        if (nrSolvers == 1) {
    078            super.start();
    079        } else {
    080            iSynchronizationThread = new SynchronizationThread(nrSolvers);
    081            iSynchronizationThread.setPriority(THREAD_PRIORITY);
    082            iSynchronizationThread.start();
    083        }
    084    }
    085
    086    /** Returns solver's thread */
    087    @Override
    088    public Thread getSolverThread() {
    089        return iSynchronizationThread != null ? iSynchronizationThread : super.getSolverThread();
    090    }
    091
    092    /** Sets initial solution */
    093    @Override
    094    public void setInitalSolution(Model<V, T> model) {
    095        int nrSolvers = Math.min(Math.abs(getProperties().getPropertyInt("Parallel.NrSolvers", 4)), CanHoldContext.sMaxSize - 1);
    096        boolean updateMasterSolution = getProperties().getPropertyBoolean("Parallel.UpdateMasterSolution", true);
    097        setInitalSolution(new Solution<V, T>(model, nrSolvers > 1 ? new DefaultParallelAssignment<V, T>(updateMasterSolution ? 1 : 0) : new DefaultSingleAssignment<V, T>(), 0, 0));
    098    }
    099
    100    /**
    101     * Return a working (parallel) solution that contributed to the best solution last.
    102     * @return working solution
    103     */
    104    protected Solution<V, T> getWorkingSolution() {
    105        if (iSynchronizationThread != null && !hasSingleSolution()) {
    106            int idx = currentSolution().getBestIndex();
    107            if (idx < 0) idx = 0; // take the first thread solution if there was no best solution saved yet
    108            if (idx < iSynchronizationThread.iSolvers.size())
    109                return iSynchronizationThread.iSolvers.get(idx).iSolution;
    110        }
    111        return currentSolution();
    112    }
    113
    114    /**
    115     * Synchronization thread
    116     */
    117    protected class SynchronizationThread extends Thread {
    118        private int iNrSolvers;
    119        private List<SolverThread> iSolvers = new ArrayList<SolverThread>();
    120        private AssignmentThread iAssignmentThread = null;
    121
    122        SynchronizationThread(int nrSolvers) {
    123            iNrSolvers = nrSolvers;
    124        }
    125
    126        @Override
    127        public void run() {
    128            try {
    129                iStop = false;
    130                iNrFinished = 0;
    131                setName("SolverSync");
    132
    133                // Initialization
    134                iProgress = Progress.getInstance(currentSolution().getModel());
    135                iProgress.setStatus("Solving problem ...");
    136                iProgress.setPhase("Initializing solver");
    137                initSolver();
    138                onStart();
    139
    140                if (isUpdateProgress()) {
    141                    if (currentSolution().getBestInfo() == null) {
    142                        iProgress.setPhase("Searching for initial solution ...", currentSolution().getModel().variables().size());
    143                    } else {
    144                        iProgress.setPhase("Improving found solution ...");
    145                    }
    146                }
    147                sLogger.info("Initial solution:" + ToolBox.dict2string(currentSolution().getInfo(), 2));
    148                if ((iSaveBestUnassigned < 0 || iSaveBestUnassigned >= currentSolution().getAssignment().nrUnassignedVariables(currentSolution().getModel())) && (currentSolution().getBestInfo() == null || getSolutionComparator().isBetterThanBestSolution(currentSolution()))) {
    149                    if (currentSolution().getAssignment().nrAssignedVariables() == currentSolution().getModel().variables().size())
    150                        sLogger.info("Complete solution " + ToolBox.dict2string(currentSolution().getInfo(), 1) + " was found.");
    151                    currentSolution().saveBest();
    152                }
    153
    154                if (currentSolution().getModel().variables().isEmpty()) {
    155                    iProgress.error("Nothing to solve.");
    156                    iStop = true;
    157                }
    158
    159                BlockingQueue<Neighbour<V, T>> queue = null;
    160                if (hasSingleSolution() && iNrSolvers > 1 && getProperties().getPropertyBoolean("ParallelSolver.SingleSolutionQueue", false))
    161                    queue = new ArrayBlockingQueue<Neighbour<V, T>>(2 * iNrSolvers);
    162
    163                if (!iStop) {
    164                    for (int i = 1; i <= iNrSolvers; i++) {
    165                        SolverThread thread = new SolverThread(i, queue);
    166                        thread.setPriority(THREAD_PRIORITY);
    167                        thread.setName("Solver-" + i);
    168                        thread.start();
    169                        iSolvers.add(thread);
    170                    }
    171                }
    172
    173                if (queue != null) {
    174                    iAssignmentThread = new AssignmentThread(queue);
    175                    iAssignmentThread.start();
    176                }
    177
    178                int timeout = getProperties().getPropertyInt("Termination.TimeOut", 1800);
    179                double start = JProf.currentTimeSec();
    180                while (!iStop && iNrFinished < iNrSolvers) {
    181                    try {
    182                        Thread.sleep(1000);
    183                        double time = JProf.currentTimeSec() - start;
    184
    185                        // Increment progress bar
    186                        if (isUpdateProgress()) {
    187                            if (currentSolution().getBestInfo() != null && currentSolution().getModel().getBestUnassignedVariables() == 0) {
    188                                if (!"Improving found solution ...".equals(iProgress.getPhase()))
    189                                    iProgress.setPhase("Improving found solution ...");
    190                                iProgress.setProgress(Math.min(100, (int)Math.round(100 * time / timeout)));
    191                            } else if (currentSolution().getModel().getBestUnassignedVariables() > 0 && (currentSolution().getModel().countVariables() - currentSolution().getModel().getBestUnassignedVariables() > iProgress.getProgress())) {
    192                                iProgress.setProgress(currentSolution().getModel().countVariables() - currentSolution().getModel().getBestUnassignedVariables());
    193                            } else if (iSolvers.get(0).iAssignment.nrAssignedVariables() > iProgress.getProgress()) {
    194                                iProgress.setProgress(iSolvers.get(0).iAssignment.nrAssignedVariables());
    195                            }
    196                        }
    197                    } catch (InterruptedException e) {}
    198                }
    199
    200                boolean stop = iStop; iStop = true;
    201                for (SolverThread thread: iSolvers) {
    202                    try {
    203                        thread.join();
    204                    } catch (InterruptedException e) {}
    205                }
    206                if (iAssignmentThread != null) {
    207                    try {
    208                        iAssignmentThread.join();
    209                    } catch (InterruptedException e) {}
    210                }
    211
    212                // Finalization
    213                iLastSolution = iCurrentSolution;
    214
    215                iProgress.setPhase("Done", 1);
    216                iProgress.incProgress();
    217
    218                if (stop) {
    219                    sLogger.debug("Solver stopped.");
    220                    iProgress.setStatus("Solver stopped.");
    221                    onStop();
    222                } else {
    223                    sLogger.debug("Solver done.");
    224                    iProgress.setStatus("Solver done.");
    225                    onFinish();
    226                }
    227            } catch (Exception ex) {
    228                sLogger.error(ex.getMessage(), ex);
    229                iProgress.fatal("Solver synchronization failed, reason:" + ex.getMessage(), ex);
    230                iProgress.setStatus("Solver failed.");
    231                onFailure();
    232            } finally {
    233                iSynchronizationThread = null;
    234            }
    235        }
    236    }
    237
    238    /**
    239     * Create a solution that is to be used by a solver thread of the given index
    240     * @param index solver thread index
    241     * @return new solution to work with
    242     */
    243    protected Solution<V, T> createParallelSolution(int index) {
    244        Model<V, T> model = iCurrentSolution.getModel();
    245        Assignment<V, T> assignment = new DefaultParallelAssignment<V, T>(index, model, iCurrentSolution.getAssignment());
    246        model.createAssignmentContexts(assignment, true);
    247        Solution<V, T> solution = new Solution<V, T>(model, assignment);
    248        for (SolutionListener<V, T> listener: iCurrentSolution.getSolutionListeners())
    249            solution.addSolutionListener(listener);
    250        return solution;
    251    }
    252
    253    /**
    254     * Returns true if the solver works only with one solution (regardless the number of threads it is using)
    255     * @return true if the current solution is {@link DefaultSingleAssignment}
    256     */
    257    @Override
    258    public boolean hasSingleSolution() {
    259        return iCurrentSolution.getAssignment() instanceof DefaultSingleAssignment;
    260    }
    261
    262    /**
    263     * Solver thread
    264     */
    265    protected class SolverThread extends Thread {
    266        private double iStartTime;
    267        private int iIndex;
    268        private boolean iSingle;
    269        private Model<V, T> iModel;
    270        private Solution<V, T> iSolution;
    271        private Assignment<V, T> iAssignment;
    272        private BlockingQueue<Neighbour<V, T>> iQueue;
    273
    274        public SolverThread(int index, BlockingQueue<Neighbour<V, T>> queue) {
    275            iIndex = index;
    276            iSingle = hasSingleSolution();
    277            iModel = iCurrentSolution.getModel();
    278            iSolution = (iSingle || iCurrentSolution.getAssignment().getIndex() == index ? iCurrentSolution : createParallelSolution(iIndex));
    279            iAssignment = iSolution.getAssignment();
    280            iQueue = queue;
    281        }
    282
    283        @Override
    284        public void run() {
    285            iStartTime = JProf.currentTimeSec();
    286            try {
    287                boolean neighbourCheck = getProperties().getPropertyBoolean("ParallelSolver.SingleSolutionNeighbourCheck", false);
    288                boolean tryLazyFirst = getProperties().getPropertyBoolean("ParallelSolver.SingleSolutionTryLazyFirst", false);
    289
    290                while (!iStop) {
    291                    // Break if cannot continue
    292                    if (!getTerminationCondition().canContinue(iSolution)) break;
    293
    294                    // Create a sub-solution if needed
    295                    Solution<V, T> current = iSolution;
    296                    if (iSingle) {
    297                        current = new Solution<V, T>(iModel, iModel.createInheritedAssignment(iSolution, iIndex), iSolution.getIteration(), iSolution.getTime());
    298                        current.addSolutionListener(new SolutionListener<V, T>() {
    299                            @Override
    300                            public void solutionUpdated(Solution<V, T> solution) {
    301                            }
    302
    303                            @Override
    304                            public void getInfo(Solution<V, T> solution, Map<String, String> info) {
    305                            }
    306
    307                            @Override
    308                            public void getInfo(Solution<V, T> solution, Map<String, String> info, Collection<V> variables) {
    309                            }
    310
    311                            @Override
    312                            public void bestCleared(Solution<V, T> solution) {
    313                            }
    314
    315                            @Override
    316                            public void bestSaved(Solution<V, T> solution) {
    317                            }
    318
    319                            @Override
    320                            public void bestRestored(Solution<V, T> solution) {
    321                                iSolution.restoreBest();
    322                            }
    323                        });
    324                    }
    325
    326                    // Neighbour selection
    327                    Neighbour<V, T> neighbour = null;
    328                    try {
    329                        neighbour = getNeighbourSelection().selectNeighbour(current);
    330                    } catch (Exception e) {
    331                        sLogger.debug("Failed to select a neighbour: " + (e.getMessage() == null ? e.getClass().getSimpleName() : e.getMessage()), e);
    332                    }
    333                    for (SolverListener<V, T> listener : iSolverListeners) {
    334                        if (!listener.neighbourSelected(iAssignment, iSolution.getIteration(), neighbour)) {
    335                            neighbour = null;
    336                            continue;
    337                        }
    338                    }
    339
    340                    double time = JProf.currentTimeSec() - iStartTime;
    341                    if (neighbour == null) {
    342                        sLogger.debug("No neighbour selected.");
    343                        // still update the solution (increase iteration etc.)
    344                        iSolution.update(time, false);
    345                        continue;
    346                    }
    347
    348                    if (iSingle) {
    349                        if (iQueue != null) {
    350                            do {
    351                                if (iQueue.offer(neighbour, 1000, TimeUnit.MILLISECONDS)) break;
    352                            } while (!iStop && getTerminationCondition().canContinue(iSolution));
    353                            continue;
    354                        }
    355
    356                        Map<V, T> assignments = null;
    357                        try {
    358                            assignments = neighbour.assignments();
    359                        } catch (Exception e) {
    360                            sLogger.error("Failed to enumerate " + neighbour.getClass().getSimpleName(), e);
    361                        }
    362                        if (assignments == null) {
    363                            sLogger.debug("No assignments returned.");
    364                            // still update the solution (increase iteration etc.)
    365                            iSolution.update(time, false);
    366                            continue;
    367                        }
    368
    369                        if (tryLazyFirst && neighbour instanceof LazyNeighbour) {
    370                            LazyNeighbour<V, T> lazy = (LazyNeighbour<V, T>)neighbour;
    371                            double before = current.getModel().getTotalValue(current.getAssignment());
    372                            neighbour.assign(current.getAssignment(), current.getIteration());
    373                            double after = current.getModel().getTotalValue(current.getAssignment());
    374                            if (!lazy.getAcceptanceCriterion().accept(current.getAssignment(), lazy, after - before))
    375                                continue;
    376                        }
    377
    378                        // Assign selected value to the selected variable
    379                        Lock lock = iSolution.getLock().writeLock();
    380                        lock.lock();
    381                        try {
    382                            LazyNeighbourAcceptanceCriterion<V,T> lazy = null;
    383                            double before = 0, value = 0;
    384                            if (neighbour instanceof LazyNeighbour) {
    385                                before = iSolution.getModel().getTotalValue(iSolution.getAssignment());
    386                                lazy = ((LazyNeighbour<V, T>)neighbour).getAcceptanceCriterion();
    387                            } else if (neighbourCheck) {
    388                                before = iSolution.getModel().getTotalValue(iSolution.getAssignment());
    389                                value = neighbour.value(current.getAssignment());
    390                            }
    391                            Map<V, T> undo = new HashMap<V, T>();
    392                            for (Iterator<Map.Entry<V, T>> i = assignments.entrySet().iterator(); i.hasNext(); ) {
    393                                Map.Entry<V, T> e = i.next();
    394                                T cur = iSolution.getAssignment().getValue(e.getKey());
    395                                if (e.getValue() == null && cur == null) {
    396                                    i.remove();
    397                                } else if (cur != null && cur.equals(e.getValue())) {
    398                                    i.remove();
    399                                } else {
    400                                    undo.put(e.getKey(), iSolution.getAssignment().unassign(iSolution.getIteration(), e.getKey()));
    401                                }
    402                            }
    403                            boolean fail = false;
    404                            for (T val: assignments.values()) {
    405                                if (val == null) continue;
    406                                if (iModel.inConflict(iSolution.getAssignment(), val)) {
    407                                    fail = true; break;
    408                                }
    409                                iSolution.getAssignment().assign(iSolution.getIteration(), val);
    410                            }
    411                            if (!fail) {
    412                                if (lazy != null) {
    413                                    double after = iSolution.getModel().getTotalValue(iSolution.getAssignment());
    414                                    if (!lazy.accept(iSolution.getAssignment(), (LazyNeighbour<V, T>) neighbour, after - before))
    415                                        fail = true;
    416                                } else if (neighbourCheck) {
    417                                    double after = iSolution.getModel().getTotalValue(iSolution.getAssignment());
    418                                    if (before + value < after && before < after && !getSolutionComparator().isBetterThanBestSolution(iSolution))
    419                                        fail = true;
    420                                }
    421                            }
    422                            if (fail) {
    423                                for (V var: undo.keySet())
    424                                    iSolution.getAssignment().unassign(iSolution.getIteration(), var);
    425                                for (T val: undo.values())
    426                                    if (val != null)
    427                                        iSolution.getAssignment().assign(iSolution.getIteration(), val);
    428                            }
    429                            iSolution.update(time, !fail);
    430                            if (fail) {
    431                                for (SolverListener<V, T> listener : iSolverListeners)
    432                                    listener.neighbourFailed(current.getAssignment(), iSolution.getIteration(), neighbour);
    433                                continue;
    434                            }
    435
    436                            onAssigned(iStartTime, iSolution);
    437
    438                            if ((iSaveBestUnassigned < 0 || iSaveBestUnassigned >= iSolution.getAssignment().nrUnassignedVariables(iModel)) && getSolutionComparator().isBetterThanBestSolution(iSolution)) {
    439                                iSolution.saveBest();
    440                            }
    441                        } finally {
    442                            lock.unlock();
    443                        }
    444                    } else {
    445                        // Assign selected value to the selected variable
    446                        Lock lock = iSolution.getLock().writeLock();
    447                        lock.lock();
    448                        try {
    449                            neighbour.assign(iAssignment, iSolution.getIteration());
    450                            iSolution.update(time, currentSolution());
    451                        } finally {
    452                            lock.unlock();
    453                        }
    454
    455                        onAssigned(iStartTime, iSolution);
    456
    457                        if (iSaveBestUnassigned < 0 || iSaveBestUnassigned >= iAssignment.nrUnassignedVariables(iModel))
    458                            iSolution.saveBestIfImproving(currentSolution(), getSolutionComparator());
    459                    }
    460                }
    461
    462            } catch (Exception ex) {
    463                sLogger.error(ex.getMessage(), ex);
    464                iProgress.fatal(getName() + " failed, reason:" + ex.getMessage(), ex);
    465                if (iIndex == 0) {
    466                    iProgress.setStatus("Solver failed.");
    467                    onFailure();
    468                }
    469            }
    470            Lock lock = currentSolution().getLock().writeLock();
    471            lock.lock();
    472            try {
    473                iNrFinished ++;
    474            } finally {
    475                lock.unlock();
    476            }
    477        }
    478
    479    }
    480
    481    /**
    482     * Solver thread
    483     */
    484    protected class AssignmentThread extends Thread {
    485        private double iStartTime;
    486        private Solution<V, T> iSolution;
    487        private BlockingQueue<Neighbour<V, T>> iQueue;
    488
    489        public AssignmentThread(BlockingQueue<Neighbour<V, T>> queue) {
    490            setName("Assignment");
    491            setPriority(1 + THREAD_PRIORITY);
    492            iSolution = iCurrentSolution;
    493            iQueue = queue;
    494        }
    495
    496        @Override
    497        public void run() {
    498            iStartTime = JProf.currentTimeSec();
    499            try {
    500                boolean neighbourCheck = getProperties().getPropertyBoolean("ParallelSolver.SingleSolutionNeighbourCheck", false);
    501
    502                while (!iStop) {
    503                    // Break if cannot continue
    504                    if (!getTerminationCondition().canContinue(iSolution)) break;
    505
    506                    // Create a sub-solution if needed
    507                    Neighbour<V, T> neighbour = iQueue.poll(1000, TimeUnit.MILLISECONDS);
    508
    509                    if (neighbour == null) continue;
    510
    511                    double time = JProf.currentTimeSec() - iStartTime;
    512
    513                    Map<V, T> assignments = null;
    514                    try {
    515                        assignments = neighbour.assignments();
    516                    } catch (Exception e) {
    517                        sLogger.error("Failed to enumerate " + neighbour.getClass().getSimpleName(), e);
    518                    }
    519                    if (assignments == null) {
    520                        sLogger.debug("No assignments returned.");
    521                        // still update the solution (increase iteration etc.)
    522                        iSolution.update(time, false);
    523                        continue;
    524                    }
    525
    526                    // Assign selected value to the selected variable
    527                    Lock lock = iSolution.getLock().writeLock();
    528                    lock.lock();
    529                    try {
    530                        LazyNeighbourAcceptanceCriterion<V,T> lazy = null;
    531                        double before = 0, value = 0;
    532                        if (neighbour instanceof LazyNeighbour) {
    533                            before = iSolution.getModel().getTotalValue(iSolution.getAssignment());
    534                            lazy = ((LazyNeighbour<V, T>)neighbour).getAcceptanceCriterion();
    535                        } else if (neighbourCheck) {
    536                            before = iSolution.getModel().getTotalValue(iSolution.getAssignment());
    537                            value = neighbour.value(iSolution.getAssignment());
    538                        }
    539                        Map<V, T> undo = new HashMap<V, T>();
    540                        for (V var: assignments.keySet())
    541                            undo.put(var, iSolution.getAssignment().unassign(iSolution.getIteration(), var));
    542                        boolean fail = false;
    543                        for (T val: assignments.values()) {
    544                            if (val == null) continue;
    545                            if (iSolution.getModel().inConflict(iSolution.getAssignment(), val)) {
    546                                fail = true; break;
    547                            }
    548                            iSolution.getAssignment().assign(iSolution.getIteration(), val);
    549                        }
    550                        if (!fail) {
    551                            if (lazy != null) {
    552                                double after = iSolution.getModel().getTotalValue(iSolution.getAssignment());
    553                                if (!lazy.accept(iSolution.getAssignment(), (LazyNeighbour<V, T>) neighbour, after - before))
    554                                    fail = true;
    555                            } else if (neighbourCheck) {
    556                                double after = iSolution.getModel().getTotalValue(iSolution.getAssignment());
    557                                if (before + value < after && before < after && !getSolutionComparator().isBetterThanBestSolution(iSolution))
    558                                    fail = true;
    559                            }
    560                        }
    561                        if (fail) {
    562                            for (V var: undo.keySet())
    563                                iSolution.getAssignment().unassign(iSolution.getIteration(), var);
    564                            for (T val: undo.values())
    565                                if (val != null)
    566                                    iSolution.getAssignment().assign(iSolution.getIteration(), val);
    567                        }
    568                        iSolution.update(time, !fail);
    569                        if (fail) {
    570                            for (SolverListener<V, T> listener : iSolverListeners)
    571                                listener.neighbourFailed(iSolution.getAssignment(), iSolution.getIteration(), neighbour);
    572                            continue;
    573                        }
    574
    575                        onAssigned(iStartTime, iSolution);
    576
    577                        if ((iSaveBestUnassigned < 0 || iSaveBestUnassigned >= iSolution.getAssignment().nrUnassignedVariables(iSolution.getModel())) && getSolutionComparator().isBetterThanBestSolution(iSolution)) {
    578                            iSolution.saveBest();
    579                        }
    580                    } finally {
    581                        lock.unlock();
    582                    }
    583                }
    584
    585            } catch (Exception ex) {
    586                sLogger.error(ex.getMessage(), ex);
    587                iProgress.fatal(getName() + " failed, reason:" + ex.getMessage(), ex);
    588            }
    589            Lock lock = currentSolution().getLock().writeLock();
    590            lock.lock();
    591            try {
    592                iNrFinished ++;
    593            } finally {
    594                lock.unlock();
    595            }
    596        }
    597
    598    }
    599
    600}