1  #region License Information


2  /* HeuristicLab


3  * Copyright (C) 20022015 Joseph Helm and Heuristic and Evolutionary Algorithms Laboratory (HEAL)


4  *


5  * This file is part of HeuristicLab.


6  *


7  * HeuristicLab is free software: you can redistribute it and/or modify


8  * it under the terms of the GNU General Public License as published by


9  * the Free Software Foundation, either version 3 of the License, or


10  * (at your option) any later version.


11  *


12  * HeuristicLab is distributed in the hope that it will be useful,


13  * but WITHOUT ANY WARRANTY; without even the implied warranty of


14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the


15  * GNU General Public License for more details.


16  *


17  * You should have received a copy of the GNU General Public License


18  * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.


19  */


20  #endregion


21 


22  using System;


23  using System.Linq;


24  using HeuristicLab.Core;


25  using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;


26  using HeuristicLab.Common;


27 


28  namespace HeuristicLab.Problems.BinPacking2D {


29  [Item("PackingRatio Evaluator (2d)", "Calculates the ratio between packed and unpacked space.")]


30  [StorableClass]


31  public class PackingRatioEvaluator : Item, IEvaluator {


32 


33  [StorableConstructor]


34  protected PackingRatioEvaluator(bool deserializing) : base(deserializing) { }


35  protected PackingRatioEvaluator(PackingRatioEvaluator original, Cloner cloner)


36  : base(original, cloner) {


37  }


38  public PackingRatioEvaluator() : base() { }


39  public override IDeepCloneable Clone(Cloner cloner) {


40  return new PackingRatioEvaluator(this, cloner);


41  }


42 


43  #region IEvaluator Members


44  public double Evaluate(Solution solution) {


45  return CalculatePackingRatio(solution);


46  }


47 


48  /*


49  Falkenauer:1996  A Hybrid Grouping Genetic Algorithm for Bin Packing


50 


51  fBPP = (SUM[i=1..N](Fi / C)^k)/N


52  N.......the number of bins used in the solution,


53  Fi......the sum of sizes of the items in the bin i (the fill of the bin),


54  C.......the bin capacity and


55  k.......a constant, k>1.


56  */


57  public static double CalculatePackingRatio(Solution solution) {


58  int nrOfBins = solution.NrOfBins;


59  double result = 0;


60  const double k = 2;


61  for (int i = 0; i < nrOfBins; i++) {


62  double f = solution.BinPackings[i].ItemMeasures.Sum(kvp => kvp.Value.Volume);


63  double c = solution.BinPackings[i].BinMeasures.Volume;


64  result += Math.Pow(f / c, k);


65  }


66 


67  result = result / nrOfBins;


68  return result;


69  }


70 


71  #endregion


72  }


73  }

