1 | #region License Information
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2 | /* HeuristicLab
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3 | * Copyright (C) 2002-2012 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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4 | *
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5 | * This file is part of HeuristicLab.
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6 | *
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7 | * HeuristicLab is free software: you can redistribute it and/or modify
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8 | * it under the terms of the GNU General Public License as published by
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9 | * the Free Software Foundation, either version 3 of the License, or
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10 | * (at your option) any later version.
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11 | *
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12 | * HeuristicLab is distributed in the hope that it will be useful,
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 | * GNU General Public License for more details.
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16 | *
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17 | * You should have received a copy of the GNU General Public License
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18 | * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
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19 | */
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20 | #endregion
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21 |
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22 | using System;
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23 | using HeuristicLab.Data;
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24 | using HeuristicLab.Problems.LinearAssignment;
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25 |
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26 | namespace HeuristicLab.Problems.QuadraticAssignment {
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27 | public static class GilmoreLawlerBoundCalculator {
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28 | public static double CalculateLowerBound(DoubleMatrix weights, DoubleMatrix distances) {
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29 | int N = weights.Rows;
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30 | DoubleMatrix sortedWeights = SortEachRowExceptDiagonal(weights), sortedDistances = SortEachRowExceptDiagonal(distances);
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31 |
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32 | DoubleMatrix costs = new DoubleMatrix(N, N);
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33 | for (int i = 0; i < N; i++) {
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34 | for (int j = 0; j < N; j++) {
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35 | for (int k = 0; k < N - 1; k++)
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36 | costs[i, j] += sortedWeights[i, k] * sortedDistances[j, N - 2 - k];
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37 | costs[i, j] += weights[i, i] * distances[j, j];
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38 | }
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39 | }
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40 |
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41 | double result;
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42 | LinearAssignmentProblemSolver.Solve(costs, out result);
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43 | return result;
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44 | }
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45 |
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46 | private static DoubleMatrix SortEachRowExceptDiagonal(DoubleMatrix matrix) {
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47 | var result = new DoubleMatrix(matrix.Rows, matrix.Columns);
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48 |
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49 | double[] row = new double[matrix.Rows - 1];
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50 | for (int i = 0; i < matrix.Rows; i++) {
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51 | int counter = 0;
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52 | for (int j = 0; j < matrix.Columns; j++)
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53 | if (i != j) row[counter++] = matrix[i, j];
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54 | Array.Sort(row);
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55 | for (int k = 0; k < matrix.Columns - 1; k++)
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56 | result[i, k] = row[k];
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57 | result[i, matrix.Columns - 1] = matrix[i, i];
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58 | }
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59 | return result;
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60 | }
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61 | }
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62 | }
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