Examples with Solver org.cpsolver.ifs.solver.Solver used on opensource projects

Example 1 with Solver

use of org.cpsolver.ifs.solver.Solver in project cpsolver by UniTime.

the class Test method main.

/**
 * Main program
 *
 * @param args
 *            problem property file, input file (optional, may be set by
 *            General.Input property), output file (optional, may be set by
 *            General.OutputFile property)
 */
public static void main(String[] args) {
    try {
        DataProperties cfg = new DataProperties();
        cfg.setProperty("Termination.StopWhenComplete", "false");
        cfg.setProperty("Termination.TimeOut", "1800");
        cfg.setProperty("General.SaveBestUnassigned", "-1");
        cfg.setProperty("Neighbour.Class", "org.cpsolver.exam.heuristics.ExamNeighbourSelection");
        if (args.length >= 1) {
            cfg.load(new FileInputStream(args[0]));
            cfg.setProperty("General.Config", new File(args[0]).getName());
        }
        cfg.putAll(System.getProperties());
        File inputFile = new File("c:\\test\\exam\\exam1070.xml");
        if (args.length >= 2) {
            inputFile = new File(args[1]);
        }
        ToolBox.setSeed(cfg.getPropertyLong("General.Seed", Math.round(Long.MAX_VALUE * Math.random())));
        cfg.setProperty("General.Input", inputFile.toString());
        String outName = inputFile.getName();
        if (outName.indexOf('.') >= 0)
            outName = outName.substring(0, outName.lastIndexOf('.')) + "s.xml";
        File outFile = new File(inputFile.getParentFile(), outName);
        if (args.length >= 3) {
            outFile = new File(args[2]);
            if (outFile.exists() && outFile.isDirectory())
                outFile = new File(outFile, outName);
            if (!outFile.exists() && !outFile.getName().endsWith(".xml"))
                outFile = new File(outFile, outName);
        }
        if (outFile.getParentFile() != null)
            outFile.getParentFile().mkdirs();
        cfg.setProperty("General.OutputFile", outFile.toString());
        cfg.setProperty("General.Output", outFile.getParent());
        String logName = outFile.getName();
        if (logName.indexOf('.') >= 0)
            logName = logName.substring(0, logName.lastIndexOf('.')) + ".log";
        ToolBox.setupLogging(new File(outFile.getParent(), logName), "true".equals(System.getProperty("debug", "false")));
        ExamModel model = new ExamModel(cfg);
        Document document = (new SAXReader()).read(new File(cfg.getProperty("General.Input")));
        int nrSolvers = cfg.getPropertyInt("Parallel.NrSolvers", 1);
        Assignment<Exam, ExamPlacement> assignment = (nrSolvers <= 1 ? new DefaultSingleAssignment<Exam, ExamPlacement>() : new DefaultParallelAssignment<Exam, ExamPlacement>());
        model.load(document, assignment);
        Solver<Exam, ExamPlacement> solver = (nrSolvers == 1 ? new Solver<Exam, ExamPlacement>(cfg) : new ParallelSolver<Exam, ExamPlacement>(cfg));
        solver.setInitalSolution(new Solution<Exam, ExamPlacement>(model, assignment));
        solver.currentSolution().addSolutionListener(new SolutionListener<Exam, ExamPlacement>() {

            @Override
            public void solutionUpdated(Solution<Exam, ExamPlacement> solution) {
            }

            @Override
            public void getInfo(Solution<Exam, ExamPlacement> solution, Map<String, String> info) {
            }

            @Override
            public void getInfo(Solution<Exam, ExamPlacement> solution, Map<String, String> info, Collection<Exam> variables) {
            }

            @Override
            public void bestCleared(Solution<Exam, ExamPlacement> solution) {
            }

            @Override
            public void bestSaved(Solution<Exam, ExamPlacement> solution) {
                ExamModel m = (ExamModel) solution.getModel();
                Assignment<Exam, ExamPlacement> a = solution.getAssignment();
                if (sLog.isInfoEnabled()) {
                    sLog.info("**BEST[" + solution.getIteration() + "]** " + (m.variables().size() > a.nrAssignedVariables() ? "V:" + a.nrAssignedVariables() + "/" + m.variables().size() + " - " : "") + "T:" + new DecimalFormat("0.00").format(m.getTotalValue(a)) + " " + m.toString(a) + (solution.getFailedIterations() > 0 ? ", F:" + sDoubleFormat.format(100.0 * solution.getFailedIterations() / solution.getIteration()) + "%" : ""));
                }
            }

            @Override
            public void bestRestored(Solution<Exam, ExamPlacement> solution) {
            }
        });
        Runtime.getRuntime().addShutdownHook(new ShutdownHook(solver));
        solver.start();
        try {
            solver.getSolverThread().join();
        } catch (InterruptedException e) {
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Example 2 with Solver

use of org.cpsolver.ifs.solver.Solver in project cpsolver by UniTime.

the class Test method testMPP.

private static void testMPP(DataProperties properties) {
    try {
        FileInputStream fis = new FileInputStream(properties.getProperty("General.Input") + ".pl");
        List<PrologFile.Term> v1 = PrologFile.readTermsFromStream(fis, "objects");
        fis.close();
        fis = new FileInputStream(properties.getProperty("General.Input") + ".solution");
        List<PrologFile.Term> v2 = PrologFile.readTermsFromStream(fis, "assigned");
        fis.close();
        fis = new FileInputStream(properties.getProperty("General.Input") + ".mpp");
        List<PrologFile.Term> v3 = PrologFile.readTermsFromStream(fis, "perturbation");
        fis.close();
        PrintWriter res = new PrintWriter(new FileWriter(properties.getProperty("General.Output") + File.separator + "result.pl"));
        PrintWriter stat = new PrintWriter(new FileWriter(properties.getProperty("General.Output") + File.separator + "stat.pl"));
        PrintWriter txt = new PrintWriter(new FileWriter(properties.getProperty("General.Output") + File.separator + "stat.csv"));
        txt.println("pert;time[s];timeRMS;assigned;assignedRMS;perturbations;perturbationsRMS;iters;itersRMS");
        java.text.DecimalFormat nf = new java.text.DecimalFormat("0.000", new java.text.DecimalFormatSymbols(Locale.US));
        // gen80_22_initial().getRectangles().size();
        int size = -1;
        int tests = properties.getPropertyInt("Rpp.NrTests", 10);
        int step = properties.getPropertyInt("Rpp.Step", 4);
        int min = properties.getPropertyInt("Rpp.Min", 0);
        int max = properties.getPropertyInt("Rpp.Max", -1);
        for (int i = min; size == -1 || i <= (max > 0 ? Math.min(max, size) : size); i += step) {
            double time = 0;
            long assigned = 0;
            long perturbation = 0;
            long iters = 0;
            double time2 = 0;
            long assigned2 = 0;
            long perturbation2 = 0;
            long iters2 = 0;
            for (int t = 1; t <= tests; t++) {
                RPPModel m = loadModel(properties.getPropertyInt("Rpp.ProblemWidth", 40), properties.getPropertyInt("Rpp.ProblemHeight", 14), v1, v2, v3, i, t);
                if (size < 0)
                    size = m.variables().size();
                Solver<Rectangle, Location> s = new Solver<Rectangle, Location>(properties);
                s.setInitalSolution(m);
                s.start();
                s.getSolverThread().join();
                Solution<Rectangle, Location> best = s.currentSolution();
                best.restoreBest();
                res.println("result(" + t + "," + i + "," + nf.format(best.getBestTime()) + "," + (best.getModel().variables().size() - best.getModel().getBestUnassignedVariables()) + "," + best.getBestIteration() + ",");
                Collection<Rectangle> notPlaced = best.getModel().bestUnassignedVariables(best.getAssignment());
                if (notPlaced == null)
                    notPlaced = new ArrayList<Rectangle>();
                res.print("  unassigned(" + (2 * notPlaced.size()) + "/[");
                for (Iterator<Rectangle> it = notPlaced.iterator(); it.hasNext(); ) {
                    Rectangle rect = it.next();
                    res.print(rect.getName() + "X," + rect.getName() + "Y" + (it.hasNext() ? "," : ""));
                }
                res.println("]),");
                StringBuffer sb = new StringBuffer();
                int perts = 0;
                for (Rectangle rect : ((RPPModel) best.getModel()).variables()) {
                    if (rect.getBestAssignment() != null && (rect.getInitialAssignment() == null || !rect.getBestAssignment().equals(rect.getInitialAssignment()))) {
                        sb.append(sb.length() == 0 ? "" : ",");
                        sb.append(rect.getName() + "X-" + (rect.getBestAssignment()).getX());
                        sb.append(sb.length() == 0 ? "" : ",");
                        sb.append(rect.getName() + "Y-" + (rect.getBestAssignment()).getY());
                        perts++;
                    }
                    if (rect.getBestAssignment() == null) {
                        perts++;
                    }
                }
                res.println("  perturbations(" + (2 * perts) + "/[" + sb + "])");
                res.println(").");
                res.flush();
                iters += best.getBestIteration();
                iters2 += (best.getBestIteration() * best.getBestIteration());
                time += best.getBestTime();
                time2 += (best.getBestTime() * best.getBestTime());
                assigned += (best.getModel().variables().size() - best.getModel().getBestUnassignedVariables());
                assigned2 += (best.getModel().variables().size() - best.getModel().getBestUnassignedVariables()) * (best.getModel().variables().size() - best.getModel().getBestUnassignedVariables());
                perturbation += perts;
                perturbation2 += perts * perts;
            }
            txt.println(i + ";" + nf.format(time / tests) + ";" + nf.format(ToolBox.rms(tests, time, time2)) + ";" + nf.format(((double) assigned) / tests) + ";" + nf.format(ToolBox.rms(tests, assigned, assigned2)) + ";" + nf.format(((double) perturbation) / tests) + ";" + nf.format(ToolBox.rms(tests, perturbation, perturbation2)) + ";" + nf.format(((double) iters) / tests) + ";" + nf.format(ToolBox.rms(tests, iters, iters2)));
            txt.flush();
            stat.println("averages( initperturbations( " + i + " ), time( " + nf.format(time / tests) + " ), assigned( " + nf.format(((double) assigned) / tests) + " ), perturbations( " + nf.format(((double) perturbation) / tests) + " ) ).");
            stat.println("deviations( initperturbations( " + i + " ), time( " + nf.format(ToolBox.rms(tests, time, time2)) + " ), assigned( " + nf.format(ToolBox.rms(tests, assigned, assigned2)) + " ), perturbations( " + nf.format(ToolBox.rms(tests, perturbation, perturbation2)) + " ) ).");
            stat.flush();
        }
        res.close();
        txt.close();
        stat.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Example 3 with Solver

use of org.cpsolver.ifs.solver.Solver in project cpsolver by UniTime.

the class Test method test.

private static void test(DataProperties properties) {
    try {
        int tests = properties.getPropertyInt("Rpp.NrTests", 10);
        int min = properties.getPropertyInt("Rpp.Min", 0);
        int max = properties.getPropertyInt("Rpp.Max", -1);
        PrintWriter res = new PrintWriter(new FileWriter(properties.getProperty("General.Output") + File.separator + "result.pl"));
        PrintWriter stat = new PrintWriter(new FileWriter(properties.getProperty("General.Output") + File.separator + "stat.pl"));
        PrintWriter txt = new PrintWriter(new FileWriter(properties.getProperty("General.Output") + File.separator + "stat.csv"));
        txt.println("gen;time[s];timeRMS;assigned;assignedRMS;iters;itersRMS");
        java.text.DecimalFormat nf = new java.text.DecimalFormat("0.000", new java.text.DecimalFormatSymbols(Locale.US));
        for (int genNr = min; genNr <= max; genNr++) {
            FileInputStream fis = new FileInputStream(properties.getProperty("General.Input") + File.separator + "gen" + genNr + ".pl");
            List<PrologFile.Term> v1 = PrologFile.readTermsFromStream(fis, "objects");
            fis.close();
            double time = 0;
            long assigned = 0;
            long iters = 0;
            double time2 = 0;
            long assigned2 = 0;
            long iters2 = 0;
            for (int t = 1; t <= tests; t++) {
                RPPModel m = loadModel(properties.getPropertyInt("Rpp.ProblemWidth", 40), properties.getPropertyInt("Rpp.ProblemHeight", 14), v1);
                Solver<Rectangle, Location> s = new Solver<Rectangle, Location>(properties);
                s.setInitalSolution(m);
                s.start();
                s.getSolverThread().join();
                Solution<Rectangle, Location> best = s.currentSolution();
                best.restoreBest();
                iters += best.getBestIteration();
                iters2 += (best.getBestIteration() * best.getBestIteration());
                time += best.getBestTime();
                time2 += (best.getBestTime() * best.getBestTime());
                assigned += (best.getModel().variables().size() - best.getModel().getBestUnassignedVariables());
                assigned2 += (best.getModel().variables().size() - best.getModel().getBestUnassignedVariables()) * (best.getModel().variables().size() - best.getModel().getBestUnassignedVariables());
                res.println("result(" + genNr + "," + t + "," + nf.format(best.getBestTime()) + "," + (best.getModel().variables().size() - best.getModel().getBestUnassignedVariables()) + "," + best.getBestIteration() + ",");
                Collection<Rectangle> notPlaced = best.getModel().bestUnassignedVariables(best.getAssignment());
                if (notPlaced == null)
                    notPlaced = new ArrayList<Rectangle>();
                res.print("  unassigned(" + (2 * notPlaced.size()) + "/[");
                for (Iterator<Rectangle> it = notPlaced.iterator(); it.hasNext(); ) {
                    Rectangle rect = it.next();
                    res.print(rect.getName() + "X," + rect.getName() + "Y" + (it.hasNext() ? "," : ""));
                }
                res.println("]),");
                int perts = 0;
                StringBuffer sb = new StringBuffer();
                for (Rectangle rect : ((RPPModel) best.getModel()).variables()) {
                    if (rect.getBestAssignment() != null) {
                        sb.append(sb.length() == 0 ? "" : ",");
                        sb.append(rect.getName() + "X-" + (rect.getBestAssignment()).getX());
                        sb.append(sb.length() == 0 ? "" : ",");
                        sb.append(rect.getName() + "Y-" + (rect.getBestAssignment()).getY());
                        perts++;
                    }
                }
                res.println("  assigned(" + (2 * perts) + "/[" + sb + "])");
                res.println(").");
                res.flush();
            }
            txt.println(genNr + ";" + nf.format(time / tests) + ";" + nf.format(ToolBox.rms(tests, time, time2)) + ";" + nf.format(((double) assigned) / tests) + ";" + nf.format(ToolBox.rms(tests, assigned, assigned2)) + ";" + nf.format(((double) iters) / tests) + ";" + nf.format(ToolBox.rms(tests, iters, iters2)));
            txt.flush();
            stat.println("averages( problem( " + genNr + " ), time( " + nf.format(time / tests) + " ), assigned( " + nf.format(((double) assigned) / tests) + " ) ).");
            stat.println("deviations( problem( " + genNr + " ), time( " + nf.format(ToolBox.rms(tests, time, time2)) + " ), assigned( " + nf.format(ToolBox.rms(tests, assigned, assigned2)) + " ) ).");
            stat.flush();
        }
        res.close();
        txt.close();
        stat.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Example 4 with Solver

use of org.cpsolver.ifs.solver.Solver in project cpsolver by UniTime.

the class Test method test2.

public static void test2(DataProperties properties) throws Exception {
    int nrTests = properties.getPropertyInt("Test.NrTests", 1);
    PrintWriter logStat = new PrintWriter(new FileWriter(properties.getProperty("General.Output") + File.separator + "output.csv"));
    PrintWriter logAvgStat = new PrintWriter(new FileWriter(properties.getProperty("General.Output") + File.separator + "avg_stat.csv"));
    logStat.println("fillFact;nrResources;testNr;time[s];iters;speed[it/s];assigned;assigned[%];value;totalValue");
    logAvgStat.println("fillFact;nrResources;time[s];RMStime[s];iters;RMSiters;speed[it/s];assigned;RMSassigned;assigned[%];value;RMSvalue");
    int nrResourcesMin = properties.getPropertyInt("Test.NrResourcesMin", -1);
    int nrResourcesMax = properties.getPropertyInt("Test.NrResourcesMax", -1);
    int nrResourcesStep = properties.getPropertyInt("Test.NrResourcesStep", 1);
    double fillFactorMin = properties.getPropertyDouble("Test.FillFactorMin", -1.0);
    double fillFactorMax = properties.getPropertyDouble("Test.FillFactorMax", -1.0);
    double fillFactorStep = properties.getPropertyDouble("Test.FillFactorStep", 0.01);
    boolean saveInit = properties.getPropertyBoolean("General.SaveInitialXML", true);
    boolean saveSol = properties.getPropertyBoolean("General.SaveSolutionXML", true);
    for (int nrResources = nrResourcesMin; nrResources <= nrResourcesMax; nrResources += nrResourcesStep) {
        for (double fillFactor = fillFactorMin; fillFactor <= fillFactorMax; fillFactor += fillFactorStep) {
            double sumTime = 0;
            double sumTime2 = 0;
            int sumIters = 0;
            int sumIters2 = 0;
            int sumAssign = 0;
            int sumAssign2 = 0;
            int sumVal = 0;
            int sumVal2 = 0;
            int sumVar = 0;
            for (int test = 1; test <= nrTests; test++) {
                if (nrResources >= 0) {
                    properties.setProperty("Generator.NrRooms", String.valueOf(nrResources));
                    properties.setProperty("Generator.NrClasses", String.valueOf(nrResources));
                    properties.setProperty("Generator.NrInstructors", String.valueOf(nrResources));
                }
                if (fillFactor >= 0.0) {
                    properties.setProperty("Generator.FillFactor", String.valueOf(fillFactor));
                }
                Assignment<Activity, Location> assignment = new DefaultSingleAssignment<Activity, Location>();
                TimetableModel m = TimetableModel.generate(properties, assignment);
                Solver<Activity, Location> s = new Solver<Activity, Location>(properties);
                if (saveInit)
                    m.saveAsXML(properties, true, null, assignment, new File(properties.getProperty("General.Output") + File.separator + "SimpleTT(" + (nrResources < 0 ? properties.getPropertyInt("Generator.NrRooms", 20) : nrResources) + "," + ((int) (100.0 * (fillFactor < 0.0 ? properties.getPropertyDouble("Generator.FillFactor", 0.8) : fillFactor) + 0.5)) + "," + properties.getPropertyInt("Generator.NrDependencies", 50) + ")_" + test + ".xml"));
                s.setInitalSolution(new Solution<Activity, Location>(m, assignment));
                s.currentSolution().clearBest();
                s.start();
                try {
                    s.getSolverThread().join();
                } catch (NullPointerException npe) {
                }
                if (s.lastSolution().getBestInfo() == null)
                    sLogger.error("No solution found :-(");
                sLogger.debug("Last solution:" + s.lastSolution().getInfo());
                Solution<Activity, Location> best = s.lastSolution();
                sLogger.debug("Best solution:" + s.lastSolution().getBestInfo());
                best.restoreBest();
                int val = 0;
                for (Activity var : ((TimetableModel) best.getModel()).assignedVariables(best.getAssignment())) val += (int) var.getAssignment(best.getAssignment()).toDouble();
                if (saveSol)
                    m.saveAsXML(properties, true, best, best.getAssignment(), new File(properties.getProperty("General.Output") + File.separator + "SimpleTT(" + (nrResources < 0 ? properties.getPropertyInt("Generator.NrRooms", 20) : nrResources) + "," + ((int) (100.0 * (fillFactor < 0.0 ? properties.getPropertyDouble("Generator.FillFactor", 0.8) : fillFactor) + 0.5)) + "," + properties.getPropertyInt("Generator.NrDependencies", 50) + ")_" + test + "_sol.xml"));
                sLogger.debug("Last solution:" + best.getInfo());
                logStat.println(sDoubleFormat.format(properties.getPropertyDouble("Generator.FillFactor", 0.0)) + ";" + sDoubleFormat.format(properties.getPropertyInt("Generator.NrRooms", 0)) + ";" + test + ";" + sDoubleFormat.format(best.getTime()) + ";" + best.getIteration() + ";" + sDoubleFormat.format((best.getIteration()) / best.getTime()) + ";" + best.getModel().assignedVariables(best.getAssignment()).size() + ";" + sDoubleFormat.format(100.0 * best.getModel().assignedVariables(best.getAssignment()).size() / best.getModel().variables().size()) + ";" + val);
                sLogger.debug("    time:         " + sDoubleFormat.format(best.getTime()) + " s");
                sLogger.debug("    iteration:    " + best.getIteration());
                sLogger.debug("    speed:        " + sDoubleFormat.format((best.getIteration()) / best.getTime()) + " it/s");
                sLogger.debug("    assigned:     " + best.getModel().assignedVariables(best.getAssignment()).size() + " (" + sDoubleFormat.format(100.0 * best.getModel().assignedVariables(best.getAssignment()).size() / best.getModel().variables().size()) + "%)");
                sLogger.debug("    value:        " + val);
                sumTime += best.getTime();
                sumTime2 += best.getTime() * best.getTime();
                sumIters += best.getIteration();
                sumIters2 += best.getIteration() * best.getIteration();
                sumAssign += best.getModel().assignedVariables(best.getAssignment()).size();
                sumAssign2 += best.getModel().assignedVariables(best.getAssignment()).size() * best.getModel().assignedVariables(best.getAssignment()).size();
                sumVal += val;
                sumVal2 += val * val;
                sumVar += m.variables().size();
                logStat.flush();
            }
            logAvgStat.println(sDoubleFormat.format(properties.getPropertyDouble("Generator.FillFactor", 0.0)) + ";" + sDoubleFormat.format(properties.getPropertyInt("Generator.NrRooms", 0)) + ";" + sDoubleFormat.format(sumTime / nrTests) + ";" + sDoubleFormat.format(ToolBox.rms(nrTests, sumTime, sumTime2)) + ";" + sDoubleFormat.format(((double) sumIters) / nrTests) + ";" + sDoubleFormat.format(ToolBox.rms(nrTests, sumIters, sumIters2)) + ";" + sDoubleFormat.format((sumIters) / sumTime) + ";" + sDoubleFormat.format(((double) sumAssign) / nrTests) + ";" + sDoubleFormat.format(ToolBox.rms(nrTests, sumAssign, sumAssign2)) + ";" + sDoubleFormat.format(100.0 * (sumAssign) / sumVar) + ";" + sDoubleFormat.format(((double) sumVal) / nrTests) + ";" + sDoubleFormat.format(ToolBox.rms(nrTests, sumVal, sumVal2)));
            logAvgStat.flush();
        }
    }
    logStat.close();
    logAvgStat.close();
}

Example 5 with Solver

use of org.cpsolver.ifs.solver.Solver in project cpsolver by UniTime.

the class Test method combineStudents.

/**
 * Combine students from the provided two files
 * @param cfg solver configuration
 * @param lastLikeStudentData a file containing last-like student data
 * @param realStudentData a file containing real student data
 * @return combined solution
 */
public static Solution<Request, Enrollment> combineStudents(DataProperties cfg, File lastLikeStudentData, File realStudentData) {
    try {
        RandomStudentFilter rnd = new RandomStudentFilter(1.0);
        StudentSectioningModel model = null;
        Assignment<Request, Enrollment> assignment = new DefaultSingleAssignment<Request, Enrollment>();
        for (StringTokenizer stk = new StringTokenizer(cfg.getProperty("Test.CombineAcceptProb", "1.0"), ","); stk.hasMoreTokens(); ) {
            double acceptProb = Double.parseDouble(stk.nextToken());
            sLog.info("Test.CombineAcceptProb=" + acceptProb);
            rnd.setProbability(acceptProb);
            StudentFilter batchFilter = new CombinedStudentFilter(new ReverseStudentFilter(new FreshmanStudentFilter()), rnd, CombinedStudentFilter.OP_AND);
            model = new StudentSectioningModel(cfg);
            StudentSectioningXMLLoader loader = new StudentSectioningXMLLoader(model, assignment);
            loader.setLoadStudents(false);
            loader.load();
            StudentSectioningXMLLoader lastLikeLoader = new StudentSectioningXMLLoader(model, assignment);
            lastLikeLoader.setInputFile(lastLikeStudentData);
            lastLikeLoader.setLoadOfferings(false);
            lastLikeLoader.setLoadStudents(true);
            lastLikeLoader.load();
            StudentSectioningXMLLoader realLoader = new StudentSectioningXMLLoader(model, assignment);
            realLoader.setInputFile(realStudentData);
            realLoader.setLoadOfferings(false);
            realLoader.setLoadStudents(true);
            realLoader.setStudentFilter(batchFilter);
            realLoader.load();
            fixWeights(model);
            fixPriorities(model);
            Solver<Request, Enrollment> solver = new Solver<Request, Enrollment>(model.getProperties());
            solver.setInitalSolution(model);
            new StudentSectioningXMLSaver(solver).save(new File(new File(model.getProperties().getProperty("General.Output", ".")), "solution-r" + ((int) (100.0 * acceptProb)) + ".xml"));
        }
        return model == null ? null : new Solution<Request, Enrollment>(model, assignment);
    } catch (Exception e) {
        sLog.error("Unable to combine students, reason: " + e.getMessage(), e);
        return null;
    }
}