Free cookie consent management tool by TermsFeed Policy Generator

source: stable/HeuristicLab.Problems.BinPacking/3.3/3D/Evaluators/PackingRatioEvaluator.cs @ 15769

Last change on this file since 15769 was 15584, checked in by swagner, 7 years ago

#2640: Updated year of copyrights in license headers on stable

File size: 2.6 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2018 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
22using System;
23using System.Linq;
24using HeuristicLab.Core;
25using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
26using HeuristicLab.Common;
27
28namespace HeuristicLab.Problems.BinPacking3D {
29  // NOTE: same implementation as for 2d problem
30  [Item("Packing-Ratio Evaluator (3d)", "Calculates the ratio between packed and unpacked space.")]
31  [StorableClass]
32  public class PackingRatioEvaluator : Item, IEvaluator {
33
34    [StorableConstructor]
35    protected PackingRatioEvaluator(bool deserializing) : base(deserializing) { }
36    protected PackingRatioEvaluator(PackingRatioEvaluator original, Cloner cloner)
37      : base(original, cloner) {
38    }
39    public PackingRatioEvaluator() : base() { }
40    public override IDeepCloneable Clone(Cloner cloner) {
41      return new PackingRatioEvaluator(this, cloner);
42    }
43
44    #region IEvaluator Members
45    public double Evaluate(Solution solution) {
46      return CalculatePackingRatio(solution);
47    }
48
49    /*
50        Falkenauer:1996 - A Hybrid Grouping Genetic Algorithm for Bin Packing
51       
52        fBPP = (SUM[i=1..N](Fi / C)^k)/N
53        N.......the number of bins used in the solution,
54        Fi......the sum of sizes of the items in the bin i (the fill of the bin),
55        C.......the bin capacity and
56        k.......a constant, k>1.
57     */
58    public static double CalculatePackingRatio(Solution solution) {
59      int nrOfBins = solution.NrOfBins;
60      double result = 0;
61      const double k = 2;
62      for (int i = 0; i < nrOfBins; i++) {
63        double f = solution.Bins[i].Items.Sum(kvp => kvp.Value.Volume);
64        double c = solution.Bins[i].BinShape.Volume;
65        result += Math.Pow(f / c, k);
66      }
67
68      result = result / nrOfBins;
69      return result;
70    }
71
72    #endregion
73  }
74}
Note: See TracBrowser for help on using the repository browser.