[13484] | 1 | #region License Information
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| 2 | /* HeuristicLab
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[16453] | 3 | * Copyright (C) 2002-2019 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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[13484] | 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 System.Collections.Generic;
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| 24 | using System.Linq;
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| 25 |
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| 26 | namespace HeuristicLab.Problems.Instances.TSPLIB {
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| 27 | public class TSPLIBHeterogeneousPTSPInstanceProvider : TSPLIBPTSPInstanceProvider {
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| 28 |
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| 29 | public override string Name {
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| 30 | get { return "TSPLIB (heterogeneous symmetric PTSP)"; }
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| 31 | }
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| 32 |
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| 33 | public override IEnumerable<IDataDescriptor> GetDataDescriptors() {
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| 34 | foreach (var desc in base.GetDataDescriptors().OfType<TSPLIBDataDescriptor>()) {
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| 35 | desc.SolutionIdentifier = null;
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| 36 | yield return desc;
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| 37 | }
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| 38 | }
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| 39 |
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| 40 | protected override double[] GetProbabilities(IDataDescriptor descriptor, PTSPData instance) {
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| 41 | var random = new MarsagliaRandom(GetInstanceHash(instance.Name));
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| 42 | return Enumerable.Range(0, instance.Dimension).Select(_ => (int)Math.Round((0.1 + 0.9 * random.NextDouble()) * 100) / 100.0).ToArray();
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| 43 | }
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| 44 |
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| 45 | // Bernstein's hash function
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| 46 | private uint GetInstanceHash(string name) {
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| 47 | uint hash = 5381;
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| 48 | var len = name.Length;
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| 49 | for (var i = 0; i < len; i++)
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| 50 | unchecked { hash = ((hash * 33) + name[i]); }
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| 51 | return hash;
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| 52 | }
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| 53 |
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| 54 | /// <summary>
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| 55 | /// This class is used to randomly generate PTSP instances given the TSPLIB instances.
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| 56 | /// An own implementation of a RNG was used in order to avoid possible implementation changes
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| 57 | /// in future .NET versions which would result in entirely different instances.
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| 58 | /// </summary>
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| 59 | /// <remarks>
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| 60 | /// RNG is implemented according to George Marsaglia https://en.wikipedia.org/wiki/Multiply-with-carry
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| 61 | /// </remarks>
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| 62 | private class MarsagliaRandom {
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| 63 | /*
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| 64 | * S = 2111111111*X[n-4] + 1492*X[n-3] + 1776*X[n-2] + 5115*X[n-1] + C
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| 65 | * X[n] = S modulo 2^32
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| 66 | * C = floor(S / 2^32)
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| 67 | *
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| 68 | */
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| 69 | private readonly uint[] mem = new uint[4];
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| 70 | private uint c;
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| 71 |
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| 72 | public MarsagliaRandom(uint s) {
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| 73 | int i;
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| 74 | for (i = 0; i < mem.Length; i++) {
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| 75 | unchecked { s = s * 31294061 + 1; }
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| 76 | mem[i] = s;
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| 77 | }
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| 78 | unchecked { c = s * 31294061 + 1; }
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| 79 | }
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| 80 |
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| 81 | private uint Next() {
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| 82 | unchecked {
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| 83 | ulong wsum = 2111111111 * mem[0]
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| 84 | + 1492 * mem[1]
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| 85 | + 1776 * mem[2]
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| 86 | + 5115 * mem[3]
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| 87 | + c;
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| 88 |
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| 89 | mem[0] = mem[1];
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| 90 | mem[1] = mem[2];
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| 91 | mem[2] = mem[3];
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| 92 | mem[3] = (uint)wsum;
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| 93 | c = (uint)(wsum >> 32);
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| 94 | return mem[3];
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| 95 | }
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| 96 | }
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| 97 |
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| 98 | public double NextDouble() {
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| 99 | return (double)Next() / uint.MaxValue;
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| 100 | }
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| 101 | }
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| 102 | }
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| 103 | }
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