private static void DeleteArgumentByConsolidation(IRandom random, DefunTreeNode branch, int removedArgumentIndex)
{
// replace references to the deleted argument with random references to existing arguments
var possibleArgumentSymbols = (from sym in branch.Grammar.Symbols.OfType <Argument>()
where sym.ArgumentIndex != removedArgumentIndex
select sym).ToList();
var argNodes = from node in branch.IterateNodesPrefix().OfType <ArgumentTreeNode>()
where node.Symbol.ArgumentIndex == removedArgumentIndex
select node;
foreach (var argNode in argNodes)
{
var replacementSymbol = possibleArgumentSymbols.SampleRandom(random);
argNode.Symbol = replacementSymbol;
}
}
private static void DeletionByRandomRegeneration(IRandom random, ISymbolicExpressionTree symbolicExpressionTree, DefunTreeNode selectedDefunBranch) {
// find first invocation and replace it with a randomly generated tree
// can't find all invocations in one step because once we replaced a top level invocation
// the invocations below it are removed already
var invocationCutPoint = (from node in symbolicExpressionTree.IterateNodesPrefix()
from subtree in node.Subtrees.OfType<InvokeFunctionTreeNode>()
where subtree.Symbol.FunctionName == selectedDefunBranch.FunctionName
select new CutPoint(node, subtree)).FirstOrDefault();
while (invocationCutPoint != null) {
// deletion by random regeneration
ISymbolicExpressionTreeNode replacementTree = null;
var allowedSymbolsList = invocationCutPoint.Parent.Grammar.GetAllowedChildSymbols(invocationCutPoint.Parent.Symbol, invocationCutPoint.ChildIndex).ToList();
var weights = allowedSymbolsList.Select(s => s.InitialFrequency);
#pragma warning disable 612, 618
var selectedSymbol = allowedSymbolsList.SelectRandom(weights, random);
#pragma warning restore 612, 618
int minPossibleLength = invocationCutPoint.Parent.Grammar.GetMinimumExpressionLength(selectedSymbol);
int maxLength = Math.Max(minPossibleLength, invocationCutPoint.Child.GetLength());
int minPossibleDepth = invocationCutPoint.Parent.Grammar.GetMinimumExpressionDepth(selectedSymbol);
int maxDepth = Math.Max(minPossibleDepth, invocationCutPoint.Child.GetDepth());
replacementTree = selectedSymbol.CreateTreeNode();
if (replacementTree.HasLocalParameters)
replacementTree.ResetLocalParameters(random);
invocationCutPoint.Parent.RemoveSubtree(invocationCutPoint.ChildIndex);
invocationCutPoint.Parent.InsertSubtree(invocationCutPoint.ChildIndex, replacementTree);
ProbabilisticTreeCreator.PTC2(random, replacementTree, maxLength, maxDepth);
invocationCutPoint = (from node in symbolicExpressionTree.IterateNodesPrefix()
from subtree in node.Subtrees.OfType<InvokeFunctionTreeNode>()
where subtree.Symbol.FunctionName == selectedDefunBranch.FunctionName
select new CutPoint(node, subtree)).FirstOrDefault();
}
}
private static void DeletionByRandomRegeneration(IRandom random, ISymbolicExpressionTree symbolicExpressionTree, DefunTreeNode selectedDefunBranch)
{
// find first invocation and replace it with a randomly generated tree
// can't find all invocations in one step because once we replaced a top level invocation
// the invocations below it are removed already
var invocationCutPoint = (from node in symbolicExpressionTree.IterateNodesPrefix()
from subtree in node.Subtrees.OfType <InvokeFunctionTreeNode>()
where subtree.Symbol.FunctionName == selectedDefunBranch.FunctionName
select new CutPoint(node, subtree)).FirstOrDefault();
while (invocationCutPoint != null)
{
// deletion by random regeneration
ISymbolicExpressionTreeNode replacementTree = null;
var allowedSymbolsList = invocationCutPoint.Parent.Grammar.GetAllowedChildSymbols(invocationCutPoint.Parent.Symbol, invocationCutPoint.ChildIndex).ToList();
var weights = allowedSymbolsList.Select(s => s.InitialFrequency);
#pragma warning disable 612, 618
var selectedSymbol = allowedSymbolsList.SelectRandom(weights, random);
#pragma warning restore 612, 618
int minPossibleLength = invocationCutPoint.Parent.Grammar.GetMinimumExpressionLength(selectedSymbol);
int maxLength = Math.Max(minPossibleLength, invocationCutPoint.Child.GetLength());
int minPossibleDepth = invocationCutPoint.Parent.Grammar.GetMinimumExpressionDepth(selectedSymbol);
int maxDepth = Math.Max(minPossibleDepth, invocationCutPoint.Child.GetDepth());
replacementTree = selectedSymbol.CreateTreeNode();
if (replacementTree.HasLocalParameters)
{
replacementTree.ResetLocalParameters(random);
}
invocationCutPoint.Parent.RemoveSubtree(invocationCutPoint.ChildIndex);
invocationCutPoint.Parent.InsertSubtree(invocationCutPoint.ChildIndex, replacementTree);
ProbabilisticTreeCreator.PTC2(random, replacementTree, maxLength, maxDepth);
invocationCutPoint = (from node in symbolicExpressionTree.IterateNodesPrefix()
from subtree in node.Subtrees.OfType <InvokeFunctionTreeNode>()
where subtree.Symbol.FunctionName == selectedDefunBranch.FunctionName
select new CutPoint(node, subtree)).FirstOrDefault();
}
}
private DefunTreeNode(DefunTreeNode original, Cloner cloner)
: base(original, cloner)
{
functionName = original.functionName;
numberOfArguments = original.numberOfArguments;
}
private static bool CreateNewArgumentForDefun(IRandom random, ISymbolicExpressionTree tree, DefunTreeNode defunBranch, ArgumentTreeNode newArgumentNode)
{
// select a random cut point in the function defining branch
// the branch at the cut point is to be replaced by a new argument node
var cutPoints = (from node in defunBranch.IterateNodesPrefix()
where node.Subtrees.Count() > 0 &&
!node.IterateNodesPrefix().OfType <ArgumentTreeNode>().Any() &&
!node.IterateNodesPrefix().OfType <InvokeFunctionTreeNode>().Any()
from subtree in node.Subtrees
select new CutPoint(node, subtree)).ToList();
if (cutPoints.Count() == 0)
{
// no cut point found => abort;
return(false);
}
var selectedCutPoint = cutPoints[random.Next(cutPoints.Count)];
// replace the branch at the cut point with an argument node
var replacedBranch = selectedCutPoint.Child;
selectedCutPoint.Parent.RemoveSubtree(selectedCutPoint.ChildIndex);
selectedCutPoint.Parent.InsertSubtree(selectedCutPoint.ChildIndex, newArgumentNode);
// find all old invocations of the selected ADF and attach a cloned version of the replaced branch (with all argument-nodes expanded)
// iterate in post-fix order to make sure that the subtrees of n are already adapted when n is processed
var invocationNodes = (from node in tree.IterateNodesPostfix().OfType <InvokeFunctionTreeNode>()
where node.Symbol.FunctionName == defunBranch.FunctionName
where node.Subtrees.Count() == defunBranch.NumberOfArguments
select node).ToList();
// do this repeatedly until no matching invocations are found
while (invocationNodes.Count > 0)
{
List <ISymbolicExpressionTreeNode> newlyAddedBranches = new List <ISymbolicExpressionTreeNode>();
foreach (var invocationNode in invocationNodes)
{
// check that the invocation node really has the correct number of arguments
if (invocationNode.Subtrees.Count() != defunBranch.NumberOfArguments)
{
throw new InvalidOperationException();
}
// append a new argument branch after expanding all argument nodes
var clonedBranch = (ISymbolicExpressionTreeNode)replacedBranch.Clone();
clonedBranch = ReplaceArgumentsInBranch(clonedBranch, invocationNode.Subtrees);
invocationNode.InsertSubtree(newArgumentNode.Symbol.ArgumentIndex, clonedBranch);
newlyAddedBranches.Add(clonedBranch);
}
// iterate in post-fix order to make sure that the subtrees of n are already adapted when n is processed
invocationNodes = (from newlyAddedBranch in newlyAddedBranches
from node in newlyAddedBranch.IterateNodesPostfix().OfType <InvokeFunctionTreeNode>()
where node.Symbol.FunctionName == defunBranch.FunctionName
where node.Subtrees.Count() == defunBranch.NumberOfArguments
select node).ToList();
}
// increase expected number of arguments of function defining branch
// it's possible that the number of actually referenced arguments was reduced (all references were replaced by a single new argument)
// but the number of expected arguments is increased anyway
defunBranch.NumberOfArguments++;
defunBranch.Grammar.AddSymbol(newArgumentNode.Symbol);
defunBranch.Grammar.SetSubtreeCount(newArgumentNode.Symbol, 0, 0);
// allow the argument as child of any other symbol
GrammarModifier.SetAllowedParentSymbols(defunBranch.Grammar, selectedCutPoint.Child.Symbol, newArgumentNode.Symbol);
foreach (var subtree in tree.Root.Subtrees)
{
// when the changed function is known in the branch then update the number of arguments
var matchingSymbol = subtree.Grammar.Symbols.OfType <InvokeFunction>().Where(s => s.FunctionName == defunBranch.FunctionName).SingleOrDefault();
if (matchingSymbol != null)
{
subtree.Grammar.SetSubtreeCount(matchingSymbol, defunBranch.NumberOfArguments, defunBranch.NumberOfArguments);
foreach (var symb in subtree.Grammar.Symbols)
{
if (symb is StartSymbol || symb is ProgramRootSymbol)
{
continue;
}
if (symb.Name == matchingSymbol.Name)
{
continue; //don't allow invoke as child of invoke
}
if (subtree.Grammar.IsAllowedChildSymbol(selectedCutPoint.Parent.Symbol, symb, selectedCutPoint.ChildIndex))
{
subtree.Grammar.AddAllowedChildSymbol(matchingSymbol, symb, newArgumentNode.Symbol.ArgumentIndex);
}
}
}
}
return(true);
}
private DefunTreeNode(DefunTreeNode original, Cloner cloner)
: base(original, cloner) {
functionName = original.functionName;
numberOfArguments = original.numberOfArguments;
}
private static void DeleteArgumentByConsolidation(IRandom random, DefunTreeNode branch, int removedArgumentIndex) {
// replace references to the deleted argument with random references to existing arguments
var possibleArgumentSymbols = (from sym in branch.Grammar.Symbols.OfType<Argument>()
where sym.ArgumentIndex != removedArgumentIndex
select sym).ToList();
var argNodes = from node in branch.IterateNodesPrefix().OfType<ArgumentTreeNode>()
where node.Symbol.ArgumentIndex == removedArgumentIndex
select node;
foreach (var argNode in argNodes) {
var replacementSymbol = possibleArgumentSymbols.SampleRandom(random);
argNode.Symbol = replacementSymbol;
}
}
private static bool CreateNewArgumentForDefun(IRandom random, ISymbolicExpressionTree tree, DefunTreeNode defunBranch, ArgumentTreeNode newArgumentNode) {
// select a random cut point in the function defining branch
// the branch at the cut point is to be replaced by a new argument node
var cutPoints = (from node in defunBranch.IterateNodesPrefix()
where node.Subtrees.Count() > 0 &&
!node.IterateNodesPrefix().OfType<ArgumentTreeNode>().Any() &&
!node.IterateNodesPrefix().OfType<InvokeFunctionTreeNode>().Any()
from subtree in node.Subtrees
select new CutPoint(node, subtree)).ToList();
if (cutPoints.Count() == 0)
// no cut point found => abort;
return false;
var selectedCutPoint = cutPoints[random.Next(cutPoints.Count)];
// replace the branch at the cut point with an argument node
var replacedBranch = selectedCutPoint.Child;
selectedCutPoint.Parent.RemoveSubtree(selectedCutPoint.ChildIndex);
selectedCutPoint.Parent.InsertSubtree(selectedCutPoint.ChildIndex, newArgumentNode);
// find all old invocations of the selected ADF and attach a cloned version of the replaced branch (with all argument-nodes expanded)
// iterate in post-fix order to make sure that the subtrees of n are already adapted when n is processed
var invocationNodes = (from node in tree.IterateNodesPostfix().OfType<InvokeFunctionTreeNode>()
where node.Symbol.FunctionName == defunBranch.FunctionName
where node.Subtrees.Count() == defunBranch.NumberOfArguments
select node).ToList();
// do this repeatedly until no matching invocations are found
while (invocationNodes.Count > 0) {
List<ISymbolicExpressionTreeNode> newlyAddedBranches = new List<ISymbolicExpressionTreeNode>();
foreach (var invocationNode in invocationNodes) {
// check that the invocation node really has the correct number of arguments
if (invocationNode.Subtrees.Count() != defunBranch.NumberOfArguments) throw new InvalidOperationException();
// append a new argument branch after expanding all argument nodes
var clonedBranch = (ISymbolicExpressionTreeNode)replacedBranch.Clone();
clonedBranch = ReplaceArgumentsInBranch(clonedBranch, invocationNode.Subtrees);
invocationNode.InsertSubtree(newArgumentNode.Symbol.ArgumentIndex, clonedBranch);
newlyAddedBranches.Add(clonedBranch);
}
// iterate in post-fix order to make sure that the subtrees of n are already adapted when n is processed
invocationNodes = (from newlyAddedBranch in newlyAddedBranches
from node in newlyAddedBranch.IterateNodesPostfix().OfType<InvokeFunctionTreeNode>()
where node.Symbol.FunctionName == defunBranch.FunctionName
where node.Subtrees.Count() == defunBranch.NumberOfArguments
select node).ToList();
}
// increase expected number of arguments of function defining branch
// it's possible that the number of actually referenced arguments was reduced (all references were replaced by a single new argument)
// but the number of expected arguments is increased anyway
defunBranch.NumberOfArguments++;
defunBranch.Grammar.AddSymbol(newArgumentNode.Symbol);
defunBranch.Grammar.SetSubtreeCount(newArgumentNode.Symbol, 0, 0);
// allow the argument as child of any other symbol
GrammarModifier.SetAllowedParentSymbols(defunBranch.Grammar, selectedCutPoint.Child.Symbol, newArgumentNode.Symbol);
foreach (var subtree in tree.Root.Subtrees) {
// when the changed function is known in the branch then update the number of arguments
var matchingSymbol = subtree.Grammar.Symbols.OfType<InvokeFunction>().Where(s => s.FunctionName == defunBranch.FunctionName).SingleOrDefault();
if (matchingSymbol != null) {
subtree.Grammar.SetSubtreeCount(matchingSymbol, defunBranch.NumberOfArguments, defunBranch.NumberOfArguments);
foreach (var symb in subtree.Grammar.Symbols) {
if (symb is StartSymbol || symb is ProgramRootSymbol) continue;
if (symb.Name == matchingSymbol.Name) continue; //don't allow invoke as child of invoke
if (subtree.Grammar.IsAllowedChildSymbol(selectedCutPoint.Parent.Symbol, symb, selectedCutPoint.ChildIndex))
subtree.Grammar.AddAllowedChildSymbol(matchingSymbol, symb, newArgumentNode.Symbol.ArgumentIndex);
}
}
}
return true;
}
