1 | #region License Information
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2 | /* HeuristicLab
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3 | * Copyright (C) 2002-2018 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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4 | *
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5 | * This file is part of HeuristicLab.
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6 | *
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7 | * HeuristicLab is free software: you can redistribute it and/or modify
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8 | * it under the terms of the GNU General Public License as published by
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9 | * the Free Software Foundation, either version 3 of the License, or
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10 | * (at your option) any later version.
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11 | *
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12 | * HeuristicLab is distributed in the hope that it will be useful,
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 | * GNU General Public License for more details.
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16 | *
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17 | * You should have received a copy of the GNU General Public License
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18 | * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
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19 | */
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20 | #endregion
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21 |
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22 | using System;
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23 | using System.Linq;
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24 | using System.Threading;
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25 | using HeuristicLab.Analysis;
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26 | using HeuristicLab.Common;
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27 | using HeuristicLab.Core;
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28 | using HeuristicLab.Data;
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29 | using HeuristicLab.Parameters;
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30 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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31 |
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32 | namespace HeuristicLab.MathematicalOptimization.LinearProgramming.Algorithms.Solvers.Base {
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33 |
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34 | [StorableClass]
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35 | public class IncrementalSolver : Solver, IIncrementalSolver {
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36 |
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37 | [Storable]
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38 | protected readonly IValueParameter<TimeSpanValue> qualityUpdateIntervalParam;
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39 |
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40 | private IndexedDataRow<double> bpcRow;
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41 |
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42 | private IndexedDataRow<double> qpcRow;
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43 |
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44 | [Storable]
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45 | private IndexedDataTable<double> qualityPerClock;
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46 |
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47 | [StorableConstructor]
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48 | protected IncrementalSolver(bool deserializing)
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49 | : base(deserializing) {
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50 | }
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51 |
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52 | public IncrementalSolver() {
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53 | Parameters.Add(qualityUpdateIntervalParam =
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54 | new ValueParameter<TimeSpanValue>(nameof(QualityUpdateInterval),
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55 | "Time interval before solver is paused, results are retrieved and solver is resumed. " +
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56 | "Set to zero for no intermediate results and faster solving.", new TimeSpanValue(new TimeSpan(0, 0, 10))));
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57 | problemTypeParam.Value.ValueChanged += (sender, args) => {
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58 | if (SupportsQualityUpdate) {
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59 | if (!Parameters.Contains(qualityUpdateIntervalParam)) {
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60 | Parameters.Add(qualityUpdateIntervalParam);
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61 | }
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62 | } else {
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63 | Parameters.Remove(qualityUpdateIntervalParam);
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64 | }
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65 | };
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66 | }
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67 |
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68 | protected IncrementalSolver(IncrementalSolver original, Cloner cloner)
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69 | : base(original, cloner) {
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70 | problemTypeParam = cloner.Clone(original.problemTypeParam);
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71 | qualityUpdateIntervalParam = cloner.Clone(original.qualityUpdateIntervalParam);
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72 | if (original.qualityPerClock != null)
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73 | qualityPerClock = cloner.Clone(original.qualityPerClock);
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74 | }
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75 |
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76 | public virtual bool SupportsQualityUpdate => true;
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77 |
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78 | public TimeSpan QualityUpdateInterval {
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79 | get => qualityUpdateIntervalParam.Value.Value;
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80 | set => qualityUpdateIntervalParam.Value.Value = value;
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81 | }
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82 |
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83 | protected virtual TimeSpan TimeLimit => QualityUpdateInterval;
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84 |
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85 | public override void Solve(LinearProgrammingAlgorithm algorithm, CancellationToken cancellationToken) {
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86 | if (!SupportsQualityUpdate || QualityUpdateInterval == TimeSpan.Zero) {
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87 | base.Solve(algorithm, cancellationToken);
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88 | return;
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89 | }
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90 |
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91 | var timeLimit = algorithm.TimeLimit;
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92 | var unlimitedRuntime = timeLimit == TimeSpan.Zero;
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93 |
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94 | if (!unlimitedRuntime) {
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95 | timeLimit -= algorithm.ExecutionTime;
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96 | }
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97 |
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98 | var iterations = (long)timeLimit.TotalMilliseconds / (long)QualityUpdateInterval.TotalMilliseconds;
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99 | var remaining = timeLimit - TimeSpan.FromMilliseconds(iterations * QualityUpdateInterval.TotalMilliseconds);
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100 | var validResultStatuses = new[] { ResultStatus.NotSolved, ResultStatus.Feasible };
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101 |
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102 | while (unlimitedRuntime || iterations > 0) {
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103 | if (cancellationToken.IsCancellationRequested)
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104 | return;
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105 |
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106 | base.Solve(algorithm, TimeLimit);
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107 | UpdateQuality(algorithm);
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108 |
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109 | var resultStatus = ((EnumValue<ResultStatus>)algorithm.Results[nameof(solver.ResultStatus)].Value).Value;
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110 | if (!validResultStatuses.Contains(resultStatus))
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111 | return;
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112 |
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113 | if (!unlimitedRuntime)
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114 | iterations--;
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115 | }
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116 |
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117 | if (remaining > TimeSpan.Zero) {
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118 | base.Solve(algorithm, remaining);
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119 | UpdateQuality(algorithm);
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120 | }
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121 | }
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122 |
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123 | private void UpdateQuality(LinearProgrammingAlgorithm algorithm) {
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124 | if (!algorithm.Results.Exists(r => r.Name == "QualityPerClock")) {
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125 | qualityPerClock = new IndexedDataTable<double>("Quality per Clock");
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126 | qpcRow = new IndexedDataRow<double>("Objective Value");
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127 | bpcRow = new IndexedDataRow<double>("Bound");
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128 | algorithm.Results.AddOrUpdateResult("QualityPerClock", qualityPerClock);
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129 | }
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130 |
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131 | var resultStatus = ((EnumValue<ResultStatus>)algorithm.Results[nameof(solver.ResultStatus)].Value).Value;
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132 |
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133 | if (new[] { ResultStatus.Abnormal, ResultStatus.NotSolved, ResultStatus.Unbounded }.Contains(resultStatus))
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134 | return;
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135 |
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136 | var objective = ((DoubleValue)algorithm.Results[$"Best{nameof(solver.ObjectiveValue)}"].Value).Value;
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137 | var bound = solver.IsMip ? ((DoubleValue)algorithm.Results[$"Best{nameof(solver.ObjectiveBound)}"].Value).Value : double.NaN;
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138 | var time = algorithm.ExecutionTime.TotalSeconds;
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139 |
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140 | if (!qpcRow.Values.Any()) {
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141 | if (!double.IsInfinity(objective) && !double.IsNaN(objective)) {
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142 | qpcRow.Values.Add(Tuple.Create(time, objective));
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143 | qpcRow.Values.Add(Tuple.Create(time, objective));
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144 | qualityPerClock.Rows.Add(qpcRow);
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145 | algorithm.Results.AddOrUpdateResult($"Best{nameof(solver.ObjectiveValue)}FoundAt", new TimeSpanValue(TimeSpan.FromSeconds(time)));
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146 | }
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147 | } else {
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148 | var previousBest = qpcRow.Values.Last().Item2;
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149 | qpcRow.Values[qpcRow.Values.Count - 1] = Tuple.Create(time, objective);
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150 | if (!objective.IsAlmost(previousBest)) {
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151 | qpcRow.Values.Add(Tuple.Create(time, objective));
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152 | algorithm.Results.AddOrUpdateResult($"Best{nameof(solver.ObjectiveValue)}FoundAt", new TimeSpanValue(TimeSpan.FromSeconds(time)));
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153 | }
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154 | }
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155 |
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156 | if (!solver.IsMip)
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157 | return;
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158 |
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159 | if (!bpcRow.Values.Any()) {
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160 | if (!double.IsInfinity(bound) && !double.IsNaN(bound)) {
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161 | bpcRow.Values.Add(Tuple.Create(time, bound));
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162 | bpcRow.Values.Add(Tuple.Create(time, bound));
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163 | qualityPerClock.Rows.Add(bpcRow);
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164 | }
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165 | } else {
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166 | var previousBest = bpcRow.Values.Last().Item2;
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167 | bpcRow.Values[bpcRow.Values.Count - 1] = Tuple.Create(time, bound);
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168 | if (!bound.IsAlmost(previousBest)) {
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169 | bpcRow.Values.Add(Tuple.Create(time, bound));
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170 | }
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171 | }
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172 | }
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173 | }
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174 | }
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