source: branches/PTSP/HeuristicLab.Problems.PTSP/3.3/MoveEvaluators/TwoOpt/PTSPEstimatedInversionMovePathEvaluator.cs @ 12219

#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2015 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
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#endregion

using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Encodings.PermutationEncoding;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using System;

namespace HeuristicLab.Problems.PTSP {
  /// <summary>
  /// An operator to evaluate inversion moves (2-opt).
  /// </summary>
  [Item("PTSPInversionMovePathEvaluator", "Evaluates an inversion move (2-opt) by summing up the length of all added edges and subtracting the length of all deleted edges.")]
  [StorableClass]
  public class PTSPEstimatedInversionMovePathEvaluator : PTSPPathMoveEvaluator, IPermutationInversionMoveOperator {
    public override Type EvaluatorType {
      get { return typeof(PTSPEstimatedInversionMovePathEvaluator); }
    }
    public ILookupParameter<InversionMove> InversionMoveParameter {
      get { return (ILookupParameter<InversionMove>)Parameters["InversionMove"]; }
    }

    

    [StorableConstructor]
    protected PTSPEstimatedInversionMovePathEvaluator(bool deserializing) : base(deserializing) { }
    protected PTSPEstimatedInversionMovePathEvaluator(PTSPEstimatedInversionMovePathEvaluator original, Cloner cloner) : base(original, cloner) { }
    public PTSPEstimatedInversionMovePathEvaluator()
      : base() {
      Parameters.Add(new LookupParameter<InversionMove>("InversionMove", "The move to evaluate."));
    }

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

    public static double EvaluateByCoordinates(Permutation permutation, InversionMove move, DoubleMatrix coordinates, PTSPEstimatedInversionMovePathEvaluator evaluator) {
      int edge1source = permutation.GetCircular(move.Index1 - 1);
      int edge1target = permutation[move.Index1];
      int edge2source = permutation[move.Index2];
      int edge2target = permutation.GetCircular(move.Index2 + 1);
      if (move.Index2 - move.Index1 >= permutation.Length - 2) return 0;
      double moveQuality = 0;
      // remove two edges
      moveQuality -= evaluator.CalculateDistance(coordinates[edge1source, 0], coordinates[edge1source, 1],
            coordinates[edge1target, 0], coordinates[edge1target, 1]);
      moveQuality -= evaluator.CalculateDistance(coordinates[edge2source, 0], coordinates[edge2source, 1],
        coordinates[edge2target, 0], coordinates[edge2target, 1]);
      // add two edges
      moveQuality += evaluator.CalculateDistance(coordinates[edge1source, 0], coordinates[edge1source, 1],
        coordinates[edge2source, 0], coordinates[edge2source, 1]);
      moveQuality += evaluator.CalculateDistance(coordinates[edge1target, 0], coordinates[edge1target, 1],
        coordinates[edge2target, 0], coordinates[edge2target, 1]);
      return moveQuality;
    }

    public static double EvaluateByDistanceMatrix(Permutation permutation, InversionMove move, DistanceMatrix distanceMatrix, ItemList<ItemList<IntValue>> realizations) {
      double moveQuality = 0;
      int[] edges = new int[4];
      int[] indices = new int[4];
      edges[0] = permutation.GetCircular(move.Index1 - 1);
      indices[0] = move.Index1-1;
      if (indices[0] == -1) indices[0] = permutation.Length - 1;
      edges[1] = permutation[move.Index1];
      indices[1] = move.Index1;
      edges[2] = permutation[move.Index2];
      indices[2] = move.Index2;
      edges[3] = permutation.GetCircular(move.Index2 + 1);
      indices[3] = move.Index2+1; 
      if (indices[3] == permutation.Length + 1) indices[3] = 0;
      int[] aPosteriori = new int[4];
      foreach (ItemList<IntValue> realization in realizations) {
        for (int i = 0; i < edges.Length; i++) {
          if (realization[edges[i]].Value == 1) {
            aPosteriori[i] = edges[i];
          } else {
            int j=1;
            if (i%2==0) {
              // find nearest predecessor in realization if source edge
              while(realization[permutation.GetCircular(indices[i]-j)].Value==0) {
                j--;
              }
              aPosteriori[i] = permutation.GetCircular(indices[i] - j);
            } else {
              // find nearest successor in realization if target edge
              while(realization[permutation.GetCircular(indices[i]+j)].Value==0) {
                j++;
              }
              aPosteriori[i] = permutation.GetCircular(indices[i] + j);
            }
          }
        }
        // compute cost difference between the two a posteriori solutions
        moveQuality += distanceMatrix[aPosteriori[0], aPosteriori[2]] + distanceMatrix[aPosteriori[1], aPosteriori[3]];
        moveQuality -= distanceMatrix[aPosteriori[0], aPosteriori[1]] - distanceMatrix[aPosteriori[2], aPosteriori[3]];
      }
      // return average of cost differences
      return moveQuality / realizations.Capacity;
    }

    protected override double EvaluateByCoordinates(Permutation permutation, DoubleMatrix coordinates) {
      return EvaluateByCoordinates(permutation, InversionMoveParameter.ActualValue, coordinates, this);
    }

    protected override double EvaluateByDistanceMatrix(Permutation permutation, DistanceMatrix distanceMatrix) {
      return EvaluateByDistanceMatrix(permutation, InversionMoveParameter.ActualValue, distanceMatrix, RealizationsParameter.Value);
    }

    protected override double CalculateDistance(double x1, double y1, double x2, double y2) {
      return Math.Round(Math.Sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2)));
    }
  }
}