#region License Information
/* HeuristicLab
* Copyright (C) 2002-2018 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
*
* This file is part of HeuristicLab.
*
* HeuristicLab is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* HeuristicLab is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with HeuristicLab. If not, see .
*/
#endregion
using System;
using System.Linq;
using HeuristicLab.Core;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.Common;
namespace HeuristicLab.Problems.BinPacking3D.Evaluators {
// NOTE: same implementation as for 2d problem
[Item("Packing-Ratio Evaluator (3d)", "Calculates the ratio between packed and unpacked space.")]
[StorableClass]
public class PackingRatioEvaluator : Item, IEvaluator {
[StorableConstructor]
protected PackingRatioEvaluator(bool deserializing) : base(deserializing) { }
protected PackingRatioEvaluator(PackingRatioEvaluator original, Cloner cloner)
: base(original, cloner) {
}
public PackingRatioEvaluator() : base() { }
public override IDeepCloneable Clone(Cloner cloner) {
return new PackingRatioEvaluator(this, cloner);
}
#region IEvaluator Members
///
/// Calculates the packing ratio for the solution.
/// The packing ration is calculated as followed:
/// Falkenauer:1996 - A Hybrid Grouping Genetic Algorithm for Bin Packing
/// fBPP = (SUM[i=1..N](Fi / C)^k)/N
/// N.......the number of bins used in the solution,
/// Fi......the sum of sizes of the items in the bin i (the fill of the bin),
/// C.......the bin capacity and
/// k.......a constant, k>1.
///
///
/// Returns the calculated packing ratio of the bins in the given solution.
public double Evaluate(Solution solution) {
return CalculatePackingRatio(solution);
}
///
/// Falkenauer:1996 - A Hybrid Grouping Genetic Algorithm for Bin Packing
/// fBPP = (SUM[i=1..N](Fi / C)^k)/N
/// N.......the number of bins used in the solution,
/// Fi......the sum of sizes of the items in the bin i (the fill of the bin),
/// C.......the bin capacity and
/// k.......a constant, k>1.
///
///
///
public static double CalculatePackingRatio(Solution solution) {
int nrOfBins = solution.NrOfBins;
double result = 0;
const double k = 2;
for (int i = 0; i < nrOfBins; i++) {
double f = solution.Bins[i].Items.Sum(kvp => kvp.Value.Volume);
double c = solution.Bins[i].BinShape.Volume;
result += Math.Pow(f / c, k);
}
result = result / nrOfBins;
return result;
}
#endregion
}
}