[11458] | 1 | using System;
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| 2 | using System.Collections.Generic;
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| 3 | using System.Linq;
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| 4 | using HeuristicLab.Common;
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| 5 | using HeuristicLab.Core;
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| 6 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
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| 7 | using HeuristicLab.EvolutionTracking;
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| 8 | using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
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| 9 |
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| 10 | namespace HeuristicLab.Problems.DataAnalysis.Symbolic {
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| 11 | [Item("TraceCalculator", "Walks a genealogy graph and produces a trace of the specified subtree")]
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| 12 | [StorableClass]
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| 13 | public class TraceCalculator : Item {
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| 14 | private readonly IGenealogyGraph<ISymbolicExpressionTree> traceGraph;
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| 15 | private readonly Dictionary<IGenealogyGraphNode<ISymbolicExpressionTree>, Tuple<int, int>> traceMap;
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| 16 |
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| 17 | public IGenealogyGraph<ISymbolicExpressionTree> TraceGraph { get { return traceGraph; } }
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| 18 |
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| 19 | public TraceCalculator() {
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| 20 | traceGraph = new GenealogyGraph<ISymbolicExpressionTree>();
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| 21 | traceMap = new Dictionary<IGenealogyGraphNode<ISymbolicExpressionTree>, Tuple<int, int>>();
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| 22 | }
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| 23 |
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| 24 | protected TraceCalculator(TraceCalculator original, Cloner cloner)
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| 25 | : base(original, cloner) {
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| 26 | }
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| 27 |
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| 28 | public override IDeepCloneable Clone(Cloner cloner) {
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| 29 | return new TraceCalculator(this, cloner);
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| 30 | }
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| 31 |
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| 32 | public static IGenealogyGraph<ISymbolicExpressionTree> TraceSubtree(IGenealogyGraphNode<ISymbolicExpressionTree> node, int subtreeIndex) {
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| 33 | var tc = new TraceCalculator();
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| 34 | tc.Trace(node, subtreeIndex);
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| 35 | return tc.TraceGraph;
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| 36 | }
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| 37 |
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[11473] | 38 | /// <summary>
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| 39 | /// This method starts from a given vertex in the genealogy graph and works its way
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| 40 | /// up the ancestry trying to track the structure of the subtree given by subtreeIndex.
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| 41 | /// This method will skip genealogy graph nodes that did not have an influence on the
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| 42 | /// structure of the tracked subtree.
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| 43 | ///
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| 44 | /// Only genealogy nodes which did have an influence are added (as copies) to the trace
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| 45 | /// and are consequently called 'trace nodes'.
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| 46 | ///
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| 47 | /// The arcs connecting trace nodes hold information about the locations of the subtrees
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| 48 | /// and fragments that have been swapped in the form of a tuple (si, fi, lastSi, lastFi),
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| 49 | /// where:
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| 50 | /// - si is the subtree index in the current trace node
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| 51 | /// - fi is the fragment index in the current trace node
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| 52 | /// - lastSi is the subtree index in the previous trace node
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| 53 | /// - lastFi is the subtree index in the previous trace node
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| 54 | /// </summary>
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| 55 | /// <param name="g">The current node in the genealogy graph</param>
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| 56 | /// <param name="si">The index of the traced subtree</param>
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| 57 | /// <param name="last">The last added node in the trace graph</param>
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| 58 | public void Trace(IGenealogyGraphNode<ISymbolicExpressionTree> g, int si, IGenealogyGraphNode<ISymbolicExpressionTree> last = null) {
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| 59 | while (g.Parents.Any()) {
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| 60 | var parents = g.Parents.ToList();
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| 61 | var fragment = (IFragment<ISymbolicExpressionTreeNode>)g.InArcs.Last().Data;
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[11458] | 62 | if (fragment == null) {
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| 63 | // the node is either an elite node or (in rare cases) no fragment was transferred
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[11473] | 64 | g = parents[0];
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[11458] | 65 | continue;
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| 66 | }
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| 67 |
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| 68 | int fragmentLength = fragment.Root.GetLength();
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[11473] | 69 | int subtreeLength = g.Data.NodeAt(si).GetLength();
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[11458] | 70 |
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| 71 | #region trace crossover
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| 72 | if (parents.Count == 2) {
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[11473] | 73 | if (fragment.Index1 == si) {
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| 74 | g = parents[1];
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| 75 | si = fragment.Index2;
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[11458] | 76 | continue;
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| 77 | }
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[11473] | 78 | if (fragment.Index1 < si) {
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| 79 | if (fragment.Index1 + fragmentLength > si) {
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[11458] | 80 | // fragment contains subtree
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[11473] | 81 | g = parents[1];
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| 82 | si += fragment.Index2 - fragment.Index1;
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[11458] | 83 | } else {
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| 84 | // fragment distinct from subtree
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[11473] | 85 | g = parents[0];
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| 86 | si += g.Data.NodeAt(fragment.Index1).GetLength() - fragmentLength;
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[11458] | 87 | }
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| 88 | continue;
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| 89 | }
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[11473] | 90 | if (fragment.Index1 > si) {
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| 91 | if (fragment.Index1 < si + subtreeLength) {
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[11458] | 92 | // subtree contains fragment => branching point in the fragment graph
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[11473] | 93 | var n = traceGraph.GetByContent(g.Data);
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[11458] | 94 | if (n == null) {
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[11473] | 95 | n = g.Copy();
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[11458] | 96 | traceGraph.AddVertex(n);
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[11473] | 97 | traceMap[n] = new Tuple<int, int>(si, fragment.Index1);
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[11458] | 98 | }
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| 99 |
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[11473] | 100 | Trace(parents[0], si, n);
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| 101 | Trace(parents[1], fragment.Index2, n);
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[11458] | 102 | break;
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| 103 | } else {
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| 104 | // subtree and fragment are distinct.
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[11473] | 105 | g = parents[0];
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[11458] | 106 | continue;
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| 107 | }
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| 108 | }
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| 109 | }
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| 110 | #endregion
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| 111 | #region trace mutation
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| 112 | if (parents.Count == 1) {
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[11473] | 113 | if (si == fragment.Index1) {
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| 114 | // fragment and subtree coincide
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| 115 | // since mutation can potentially alter trees quite drastically, we branch here,
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| 116 | // in order not to miss any changes
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| 117 | var n = traceGraph.GetByContent(g.Data);
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[11458] | 118 | if (n == null) {
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[11473] | 119 | n = g.Copy();
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[11458] | 120 | traceGraph.AddVertex(n);
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[11473] | 121 | traceMap[n] = new Tuple<int, int>(si, fragment.Index1);
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[11458] | 122 | }
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[11473] | 123 | Trace(parents[0], si, n);
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| 124 | break;
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| 125 | }
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| 126 | if (fragment.Index1 < si) {
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| 127 | if (si < fragment.Index1 + fragmentLength) {
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| 128 | // fragment contains subtree
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| 129 | g = parents[0];
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| 130 | si = fragment.Index2;
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| 131 | } else {
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| 132 | // fragment and subtree are distinct
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| 133 | // since the fragment occurs before the subtree in the prefix node ordering
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| 134 | // the subtree index must be adjusted according to the fragment length
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| 135 | g = parents[0];
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| 136 | si += g.Data.NodeAt(fragment.Index1).GetLength() - fragmentLength;
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[11458] | 137 | }
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[11473] | 138 | continue;
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[11458] | 139 | }
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[11473] | 140 | if (si < fragment.Index1) {
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| 141 | // subtree occurs before fragment in the prefix node ordering
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| 142 | if (fragment.Index1 < si + subtreeLength) {
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| 143 | // subtree contains fragment, we are interested to see what the subtree looked like before
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| 144 | // but we also want to keep track of what it looks like now, therefore we branch here
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| 145 | var n = traceGraph.GetByContent(g.Data);
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| 146 | if (n == null) {
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| 147 | n = g.Copy();
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| 148 | traceGraph.AddVertex(n);
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| 149 | traceMap[n] = new Tuple<int, int>(si, fragment.Index1);
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| 150 | }
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| 151 | Trace(parents[0], si, n);
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| 152 | break;
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| 153 | } else {
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| 154 | // fragment and subtree are distinct, subtree index stays the same
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| 155 | // since the subtree comes before the fragment in the prefix node ordering
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| 156 | g = parents[0];
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| 157 | continue;
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| 158 | }
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| 159 | }
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| 160 | }
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[11458] | 161 | #endregion
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[11473] | 162 | throw new InvalidOperationException("A node cannot have more than two parents");
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[11458] | 163 | }
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[11473] | 164 | // when we are out of the while the last vertex must be connected with the current one
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| 165 | ConnectLast(g, si, last);
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[11458] | 166 | }
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[11473] | 167 |
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| 168 | /// <summary>
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| 169 | /// 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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| 170 | /// of the genealogy graph node @g.
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| 171 | /// </summary>
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| 172 | /// <param name="g">The current node in the genealogy graph</param>
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| 173 | /// <param name="si">The index of the traced subtree</param>
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| 174 | /// <param name="last">The last added node in the trace graph</param>
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| 175 | private void ConnectLast(IGenealogyGraphNode<ISymbolicExpressionTree> g, int si, IGenealogyGraphNode<ISymbolicExpressionTree> last) {
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| 176 | IFragment<ISymbolicExpressionTreeNode> fragment = g.Parents.Any() ? (IFragment<ISymbolicExpressionTreeNode>)g.InArcs.Last().Data : null;
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| 177 | var n = traceGraph.GetByContent(g.Data);
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| 178 | if (n == null) {
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| 179 | n = g.Copy();
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| 180 | traceGraph.AddVertex(n);
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| 181 | }
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| 182 | int fi = fragment == null ? 0 : fragment.Index1; // fragment index
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| 183 | traceMap[n] = new Tuple<int, int>(si, fi);
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| 184 | if (last == null)
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| 185 | return;
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| 186 | var lastTraceData = traceMap[last];
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| 187 | int lastSi = lastTraceData.Item1; // last subtree index
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| 188 | int lastFi = lastTraceData.Item2; // last fragment index
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| 189 | var td = new Tuple<int, int, int, int>(si, fi, lastSi, lastFi); // trace data
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| 190 | var arc = n.InArcs.SingleOrDefault(a => a.Source == last && a.Data.Equals(td));
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| 191 | if (arc != null)
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| 192 | return;
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| 193 | arc = new GenealogyGraphArc(last, n);
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| 194 | arc.Data = td;
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| 195 | traceGraph.AddArc(arc);
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| 196 | }
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[11458] | 197 | }
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| 198 |
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| 199 | internal static class Util {
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[11473] | 200 | // shallow node copy (does not clone the data or the arcs)
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[11458] | 201 | public static IGenealogyGraphNode<ISymbolicExpressionTree> Copy(this IGenealogyGraphNode<ISymbolicExpressionTree> node) {
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| 202 | return new GenealogyGraphNode<ISymbolicExpressionTree>(node.Data) { Rank = node.Rank, Quality = node.Quality };
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| 203 | }
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| 204 | #region some helper methods for shortening the tracing code
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| 205 | public static ISymbolicExpressionTreeNode NodeAt(this ISymbolicExpressionTree tree, int index) {
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| 206 | return NodeAt(tree.Root, index);
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| 207 | }
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| 208 | public static ISymbolicExpressionTreeNode NodeAt(this ISymbolicExpressionTreeNode root, int index) {
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| 209 | return root.IterateNodesPrefix().ElementAt(index);
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| 210 | }
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| 211 | #endregion
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| 212 | }
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| 213 | }
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