source: branches/2817-BinPackingSpeedup/HeuristicLab.Problems.BinPacking/3.3/3D/Evaluators/PackingRatioEvaluator.cs @ 15617

Last change on this file since 15617 was 15617, checked in by rhanghof, 3 years ago

#2817:

  • The items can be rotated and tilted now.
  • Added pruning of extreme points in packed bins.
  • Added new packer which packs items by positioning them on the point with the minimum of wasted space. He uses rotating and tilting of items.
  • Added classes for sorting given items.
File size: 3.3 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2018 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.Evaluators {
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
46    /// <summary>
47    /// Calculates the packing ratio for the solution.
48    /// The packing ration is calculated as followed:
49    /// Falkenauer:1996 - A Hybrid Grouping Genetic Algorithm for Bin Packing
50    /// fBPP = (SUM[i=1..N](Fi / C)^k)/N
51    /// N.......the number of bins used in the solution,
52    /// Fi......the sum of sizes of the items in the bin i (the fill of the bin),
53    /// C.......the bin capacity and
54    /// k.......a constant, k>1.
55    /// </summary>
56    /// <param name="solution"></param>
57    /// <returns>Returns the calculated packing ratio of the bins in the given solution.</returns>
58    public double Evaluate(Solution solution) {
59      return CalculatePackingRatio(solution);
60    }
61
62    /// <summary>
63    /// Falkenauer:1996 - A Hybrid Grouping Genetic Algorithm for Bin Packing
64    /// fBPP = (SUM[i=1..N](Fi / C)^k)/N
65    /// N.......the number of bins used in the solution,
66    /// Fi......the sum of sizes of the items in the bin i (the fill of the bin),
67    /// C.......the bin capacity and
68    /// k.......a constant, k>1.
69    /// </summary>
70    /// <param name="solution"></param>
71    /// <returns></returns>
72    public static double CalculatePackingRatio(Solution solution) {
73      int nrOfBins = solution.NrOfBins;
74      double result = 0;
75      const double k = 2;
76      for (int i = 0; i < nrOfBins; i++) {
77        double f = solution.Bins[i].Items.Sum(kvp => kvp.Value.Volume);
78        double c = solution.Bins[i].BinShape.Volume;
79        result += Math.Pow(f / c, k);
80      }
81
82      result = result / nrOfBins;
83      return result;
84    }
85
86    #endregion
87  }
88}
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