[11493] | 1 | #region License Information
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| 2 | /* HeuristicLab
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| 3 | * Copyright (C) 2002-2014 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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[11458] | 23 | using System.Collections.Generic;
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[11493] | 24 | using System.Diagnostics;
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[11458] | 25 | using System.Linq;
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| 26 | using HeuristicLab.Common;
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| 27 | using HeuristicLab.Core;
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| 28 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
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| 29 | using HeuristicLab.EvolutionTracking;
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| 30 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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| 31 |
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| 32 | namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
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| 33 | [Item("TraceCalculator", "Walks a genealogy graph and produces a trace of the specified subtree")]
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| 34 | [StorableClass]
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| 35 | public class TraceCalculator : Item {
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| 36 | private readonly IGenealogyGraph<ISymbolicExpressionTree> traceGraph;
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| 37 | private readonly Dictionary<IGenealogyGraphNode<ISymbolicExpressionTree>, Tuple<int, int>> traceMap;
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| 38 |
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| 39 | public IGenealogyGraph<ISymbolicExpressionTree> TraceGraph { get { return traceGraph; } }
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| 40 |
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| 41 | public TraceCalculator() {
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| 42 | traceGraph = new GenealogyGraph<ISymbolicExpressionTree>();
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| 43 | traceMap = new Dictionary<IGenealogyGraphNode<ISymbolicExpressionTree>, Tuple<int, int>>();
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| 44 | }
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| 45 |
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| 46 | protected TraceCalculator(TraceCalculator original, Cloner cloner)
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| 47 | : base(original, cloner) {
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| 48 | }
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| 49 |
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| 50 | public override IDeepCloneable Clone(Cloner cloner) {
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| 51 | return new TraceCalculator(this, cloner);
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| 52 | }
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| 53 |
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| 54 | public static IGenealogyGraph<ISymbolicExpressionTree> TraceSubtree(IGenealogyGraphNode<ISymbolicExpressionTree> node, int subtreeIndex) {
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| 55 | var tc = new TraceCalculator();
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| 56 | tc.Trace(node, subtreeIndex);
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| 57 | return tc.TraceGraph;
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| 58 | }
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| 59 |
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[11476] | 60 | public IGenealogyGraph<ISymbolicExpressionTree> Trace(IGenealogyGraphNode<ISymbolicExpressionTree> node, int subtreeIndex) {
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| 61 | traceGraph.Clear();
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| 62 | traceMap.Clear();
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| 63 | Trace(node, subtreeIndex, null);
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| 64 | return traceGraph;
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| 65 | }
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| 66 |
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[11473] | 67 | /// <summary>
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| 68 | /// This method starts from a given vertex in the genealogy graph and works its way
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| 69 | /// up the ancestry trying to track the structure of the subtree given by subtreeIndex.
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| 70 | /// This method will skip genealogy graph nodes that did not have an influence on the
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| 71 | /// structure of the tracked subtree.
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| 72 | ///
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| 73 | /// Only genealogy nodes which did have an influence are added (as copies) to the trace
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| 74 | /// and are consequently called 'trace nodes'.
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| 75 | ///
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| 76 | /// The arcs connecting trace nodes hold information about the locations of the subtrees
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| 77 | /// and fragments that have been swapped in the form of a tuple (si, fi, lastSi, lastFi),
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| 78 | /// where:
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| 79 | /// - si is the subtree index in the current trace node
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| 80 | /// - fi is the fragment index in the current trace node
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| 81 | /// - lastSi is the subtree index in the previous trace node
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| 82 | /// - lastFi is the subtree index in the previous trace node
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| 83 | /// </summary>
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| 84 | /// <param name="g">The current node in the genealogy graph</param>
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| 85 | /// <param name="si">The index of the traced subtree</param>
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| 86 | /// <param name="last">The last added node in the trace graph</param>
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[11476] | 87 | private void Trace(IGenealogyGraphNode<ISymbolicExpressionTree> g, int si, IGenealogyGraphNode<ISymbolicExpressionTree> last = null) {
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[11473] | 88 | while (g.Parents.Any()) {
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| 89 | var parents = g.Parents.ToList();
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| 90 | var fragment = (IFragment<ISymbolicExpressionTreeNode>)g.InArcs.Last().Data;
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[11458] | 91 | if (fragment == null) {
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[11638] | 92 | // if (parents.Count == 2)
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| 93 | // throw new Exception("There should always be a crossover fragment.");
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[11458] | 94 | // the node is either an elite node or (in rare cases) no fragment was transferred
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[11473] | 95 | g = parents[0];
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[11458] | 96 | continue;
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| 97 | }
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| 98 |
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[11493] | 99 | int fi = fragment.Index1; // fragment index
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| 100 | int fl = fragment.Root.GetLength(); // fragment length
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| 101 | int sl = g.Data.NodeAt(si).GetLength(); // subtree length
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[11458] | 102 |
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| 103 | #region trace crossover
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| 104 | if (parents.Count == 2) {
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[11493] | 105 | if (fi == si) {
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[11473] | 106 | g = parents[1];
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| 107 | si = fragment.Index2;
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[11458] | 108 | continue;
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| 109 | }
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[11493] | 110 | if (fi < si) {
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| 111 | if (fi + fl > si) {
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[11458] | 112 | // fragment contains subtree
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[11473] | 113 | g = parents[1];
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[11493] | 114 | si += fragment.Index2 - fi;
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[11458] | 115 | } else {
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| 116 | // fragment distinct from subtree
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[11473] | 117 | g = parents[0];
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[11493] | 118 | si += g.Data.NodeAt(fi).GetLength() - fl;
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[11458] | 119 | }
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| 120 | continue;
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| 121 | }
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[11493] | 122 | if (fi > si) {
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| 123 | if (fi < si + sl) {
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[11458] | 124 | // subtree contains fragment => branching point in the fragment graph
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[11493] | 125 | var n = GetTraceNode(g, si, fi);
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[11473] | 126 | Trace(parents[0], si, n);
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| 127 | Trace(parents[1], fragment.Index2, n);
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[11458] | 128 | break;
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| 129 | } else {
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| 130 | // subtree and fragment are distinct.
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[11473] | 131 | g = parents[0];
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[11458] | 132 | continue;
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| 133 | }
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| 134 | }
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| 135 | }
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| 136 | #endregion
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| 137 | #region trace mutation
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[11493] | 138 | // mutation is handled in a simple way: we branch every time there is an overlap between the subtree and the fragment
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| 139 | // (since mutation effects can be quite unpredictable: replace branch, change node, shake tree, etc)
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[11458] | 140 | if (parents.Count == 1) {
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[11493] | 141 | Debug.Assert(fragment.Index1 == fragment.Index2);
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| 142 | // check if the subtree and the fragment overlap => branch out
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| 143 | if ((si == fi) || (si < fi && fi < si + sl) || (fi < si && si < fi + fl)) {
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| 144 | var n = GetTraceNode(g, si, fi);
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| 145 | int i = si < fi ? si : fi;
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| 146 | Trace(parents[0], i, n);
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[11473] | 147 | break;
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[11493] | 148 | } else {
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| 149 | // if they don't overlap, go up
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| 150 | g = parents[0];
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| 151 | if (fi < si)
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| 152 | si += g.Data.NodeAt(fi).GetLength() - fl;
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[11473] | 153 | continue;
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[11458] | 154 | }
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[11473] | 155 | }
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[11458] | 156 | #endregion
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[11473] | 157 | throw new InvalidOperationException("A node cannot have more than two parents");
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[11458] | 158 | }
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[11473] | 159 | // when we are out of the while the last vertex must be connected with the current one
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| 160 | ConnectLast(g, si, last);
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[11458] | 161 | }
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[11473] | 162 |
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| 163 | /// <summary>
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[11493] | 164 | /// Get the trace node from the trace graph which corresponds to node g from the genealogy graph.
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| 165 | /// If the trace graph does not contain such a node, one is created by performing a shallow copy of g, then inserted into the trace graph.
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| 166 | /// </summary>
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| 167 | /// <param name="g">The genealogy graph node</param>
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| 168 | /// <param name="si">The subtree index</param>
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| 169 | /// <param name="fi">The fragment index</param>
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| 170 | /// <returns></returns>
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| 171 | private IGenealogyGraphNode<ISymbolicExpressionTree> GetTraceNode(IGenealogyGraphNode<ISymbolicExpressionTree> g, int si, int fi) {
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| 172 | var n = traceGraph.GetByContent(g.Data);
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| 173 | if (n == null) {
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| 174 | n = g.Copy();
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| 175 | traceGraph.AddVertex(n);
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| 176 | Debug.Assert(!traceMap.ContainsKey(n));
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| 177 | traceMap[n] = new Tuple<int, int>(si, fi);
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| 178 | }
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| 179 | return n;
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| 180 | }
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| 181 |
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| 182 | /// <summary>
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[11473] | 183 | /// Connect the current node of the trace graph with the node that was previously added (@last). The current node of the trace graph is determined by the content
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| 184 | /// of the genealogy graph node @g.
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| 185 | /// </summary>
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| 186 | /// <param name="g">The current node in the genealogy graph</param>
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| 187 | /// <param name="si">The index of the traced subtree</param>
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| 188 | /// <param name="last">The last added node in the trace graph</param>
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| 189 | private void ConnectLast(IGenealogyGraphNode<ISymbolicExpressionTree> g, int si, IGenealogyGraphNode<ISymbolicExpressionTree> last) {
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| 190 | IFragment<ISymbolicExpressionTreeNode> fragment = g.Parents.Any() ? (IFragment<ISymbolicExpressionTreeNode>)g.InArcs.Last().Data : null;
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| 191 | int fi = fragment == null ? 0 : fragment.Index1; // fragment index
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[11503] | 192 | var n = GetTraceNode(g, si, fi); // will append n to the trace graph if it does not exist
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[11473] | 193 | if (last == null)
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| 194 | return;
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| 195 | var lastTraceData = traceMap[last];
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| 196 | int lastSi = lastTraceData.Item1; // last subtree index
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| 197 | int lastFi = lastTraceData.Item2; // last fragment index
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| 198 | var td = new Tuple<int, int, int, int>(si, fi, lastSi, lastFi); // trace data
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| 199 | var arc = n.InArcs.SingleOrDefault(a => a.Source == last && a.Data.Equals(td));
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[11503] | 200 | if (arc == null) {
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| 201 | arc = new GenealogyGraphArc(last, n) { Data = td };
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| 202 | traceGraph.AddArc(arc);
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| 203 | }
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[11473] | 204 | }
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[11458] | 205 | }
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| 206 |
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| 207 | internal static class Util {
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[11473] | 208 | // shallow node copy (does not clone the data or the arcs)
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[11458] | 209 | public static IGenealogyGraphNode<ISymbolicExpressionTree> Copy(this IGenealogyGraphNode<ISymbolicExpressionTree> node) {
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| 210 | return new GenealogyGraphNode<ISymbolicExpressionTree>(node.Data) { Rank = node.Rank, Quality = node.Quality };
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| 211 | }
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| 212 | #region some helper methods for shortening the tracing code
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| 213 | public static ISymbolicExpressionTreeNode NodeAt(this ISymbolicExpressionTree tree, int index) {
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| 214 | return NodeAt(tree.Root, index);
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| 215 | }
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| 216 | public static ISymbolicExpressionTreeNode NodeAt(this ISymbolicExpressionTreeNode root, int index) {
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| 217 | return root.IterateNodesPrefix().ElementAt(index);
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| 218 | }
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| 219 | #endregion
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| 220 | }
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| 221 | }
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