source: branches/LinearLinkage/HeuristicLab.Encodings.LinearLinkageEncoding/3.3/Manipulators/SwapNManipulator.cs @ 12285

#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2015 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 <http://www.gnu.org/licenses/>.
 */
#endregion

using System.Collections.Generic;
using System.Linq;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Operators;
using HeuristicLab.Optimization;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Encodings.LinearLinkageEncoding {
  [Item("Swap-n Manipulator", "")]
  [StorableClass]
  public sealed class SwapNManipulator : InstrumentedOperator, ILinearLinkageManipulator, IStochasticOperator {
    public ILookupParameter<IRandom> RandomParameter {
      get { return (ILookupParameter<IRandom>)Parameters["Random"]; }
    }

    public ILookupParameter<LinearLinkage> LLEParameter {
      get { return (ILookupParameter<LinearLinkage>)Parameters["LLE"]; }
    }

    public IValueLookupParameter<IntValue> NParameter {
      get { return (IValueLookupParameter<IntValue>)Parameters["N"]; }
    }

    [StorableConstructor]
    private SwapNManipulator(bool deserializing) : base(deserializing) { }
    private SwapNManipulator(SwapNManipulator original, Cloner cloner) : base(original, cloner) { }
    public SwapNManipulator() {
      Parameters.Add(new LookupParameter<IRandom>("Random", "The random number generator to use."));
      Parameters.Add(new LookupParameter<LinearLinkage>("LLE", "The encoding vector that is to be manipulated."));
      Parameters.Add(new ValueLookupParameter<IntValue>("N", "The number of swaps to perform.", new IntValue(2)));
    }
    public SwapNManipulator(int n)
      : this() {
      NParameter.Value = new IntValue(n);
    }

    public override IDeepCloneable Clone(Cloner cloner) {
      return new SwapNManipulator(this, cloner);
    }

    public override IOperation InstrumentedApply() {
      var random = RandomParameter.ActualValue;
      var vector = LLEParameter.ActualValue;
      var N = NParameter.ActualValue.Value;

      var grouping = vector.GetGroups().Select(x => x.ToList()).ToList();
      if (grouping.Count == 1) return base.InstrumentedApply(); // nothing can be changed
      var touched = new HashSet<int>();
      var prevGroup = random.Next(grouping.Count);
      var prevItem = random.Next(grouping[prevGroup].Count);
      touched.Add(grouping[prevGroup][prevItem]);
      for (var i = 0; i < N; i++) {
        int nextGroup = -1, nextItem = -1, tries = 0;
        do {
          if (tries >= 100) break;
          nextGroup = random.Next(grouping.Count);
          nextItem = random.Next(grouping[nextGroup].Count);
          tries++;
        } while (nextGroup == prevGroup || touched.Contains(grouping[nextGroup][nextItem]));
        if (tries >= 100) break;
        var h = grouping[nextGroup][nextItem];
        grouping[nextGroup][nextItem] = grouping[prevGroup][prevItem];
        grouping[prevGroup][prevItem] = h;
        touched.Add(h);
        prevGroup = nextGroup;
        prevItem = nextItem;
      }
      vector.SetGroups(grouping);
      return base.InstrumentedApply();
    }
  }
}