protected PercentMatrix(PercentMatrix original, Cloner cloner) : base(original, cloner) { }
private static void SelectCrossoverPoint(IRandom random, ISymbolicExpressionTree parent0, int maxBranchLength, int maxBranchDepth, out CutPoint crossoverPoint, PercentMatrix probabilities) { List<CutPoint> internalCrossoverPoints = new List<CutPoint>(); List<CutPoint> leafCrossoverPoints = new List<CutPoint>(); parent0.Root.ForEachNodePostfix((n) => { if (n.SubtreeCount > 0 && n != parent0.Root) { //avoid linq to reduce memory pressure for (int i = 0; i < n.SubtreeCount; i++) { var child = n.GetSubtree(i); if (child.GetLength() <= maxBranchLength && child.GetDepth() <= maxBranchDepth) { if (child.SubtreeCount > 0) internalCrossoverPoints.Add(new CutPoint(n, child)); else leafCrossoverPoints.Add(new CutPoint(n, child)); } } // add one additional extension point if the number of sub trees for the symbol is not full if (n.SubtreeCount < n.Grammar.GetMaximumSubtreeCount(n.Symbol)) { // empty extension point internalCrossoverPoints.Add(new CutPoint(n, n.SubtreeCount)); } } } ); List<CutPoint> allCrossoverPoints = new List<CutPoint>(); allCrossoverPoints.AddRange(internalCrossoverPoints); allCrossoverPoints.AddRange(leafCrossoverPoints); var weights = allCrossoverPoints.Select(x => probabilities[probabilities.RowNames.ToList().IndexOf(x.Child.Symbol.Name), 0]); crossoverPoint = allCrossoverPoints.SampleProportional(random, 1, weights).First(); }
protected PercentMatrix(PercentMatrix original, Cloner cloner) : base(original, cloner) { }
public ISymbolicExpressionTree Cross(IRandom random, ISymbolicExpressionTree parent0, ISymbolicExpressionTree parent1, int maxTreeLength, int maxTreeDepth, PercentMatrix probabilities) { // select a random crossover point in the first parent CutPoint crossoverPoint0; SelectCrossoverPoint(random, parent0, maxTreeLength, maxTreeDepth, out crossoverPoint0, probabilities); int childLength = crossoverPoint0.Child != null ? crossoverPoint0.Child.GetLength() : 0; // calculate the max length and depth that the inserted branch can have int maxInsertedBranchLength = maxTreeLength - (parent0.Length - childLength); int maxInsertedBranchDepth = maxTreeDepth - parent0.Root.GetBranchLevel(crossoverPoint0.Parent); List<ISymbolicExpressionTreeNode> allowedBranches = new List<ISymbolicExpressionTreeNode>(); parent1.Root.ForEachNodePostfix((n) => { if (n.GetLength() <= maxInsertedBranchLength && n.GetDepth() <= maxInsertedBranchDepth && crossoverPoint0.IsMatchingPointType(n)) allowedBranches.Add(n); }); // empty branch if (crossoverPoint0.IsMatchingPointType(null)) allowedBranches.Add(null); if (allowedBranches.Count == 0) { return parent0; } else { CutPointSymbolParameter.ActualValue = (ISymbol)crossoverPoint0.Parent.Symbol.Clone(); var selectedBranch = SelectRandomBranch(random, allowedBranches); if (crossoverPoint0.Child != null) { // manipulate the tree of parent0 in place // replace the branch in tree0 with the selected branch from tree1 crossoverPoint0.Parent.RemoveSubtree(crossoverPoint0.ChildIndex); RemovedBranchParameter.ActualValue = new SymbolicExpressionTree((ISymbolicExpressionTreeNode)crossoverPoint0.Child.Clone()); if (selectedBranch != null) { crossoverPoint0.Parent.InsertSubtree(crossoverPoint0.ChildIndex, selectedBranch); AddedBranchParameter.ActualValue = new SymbolicExpressionTree((ISymbolicExpressionTreeNode)selectedBranch.Clone()); } } else { // child is null (additional child should be added under the parent) if (selectedBranch != null) { crossoverPoint0.Parent.AddSubtree(selectedBranch); AddedBranchParameter.ActualValue = new SymbolicExpressionTree((ISymbolicExpressionTreeNode)selectedBranch.Clone()); } } return parent0; } }