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  using HeuristicLab.Data;


28  using HeuristicLab.Encodings.PackingEncoding;


29  using HeuristicLab.Problems.BinPacking;


30  using System.Collections.Generic;


31 


32  namespace HeuristicLab.Problems.BinPacking2D {


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


34  [StorableClass]


35  public class PackingRatioEvaluator : Item, IEvaluator {


36 


37  [StorableConstructor]


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


39  protected PackingRatioEvaluator(PackingRatioEvaluator original, Cloner cloner)


40  : base(original, cloner) {


41  }


42  public PackingRatioEvaluator() : base() { }


43  public override IDeepCloneable Clone(Cloner cloner) {


44  return new PackingRatioEvaluator(this, cloner);


45  }


46 


47  #region IEvaluator Members


48  public double Evaluate(Solution solution) {


49  return CalculatePackingRatio(solution);


50  }


51 


52  /*


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


54 


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


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


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


58  C.......the bin capacity and


59  k.......a constant, k>1.


60  */


61  public static double CalculatePackingRatio(Solution solution) {


62  int nrOfBins = solution.NrOfBins;


63  double result = 0;


64  const double k = 2;


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


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


67  var c = solution.BinPackings[i].BinMeasures.Volume;


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


69  }


70 


71  result = result / nrOfBins;


72  return result;


73  }


74 


75  #endregion


76  }


77  }

