#region License Information
/* HeuristicLab
* Copyright (C) 2002-2008 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
*
* This file is part of HeuristicLab.
*
* HeuristicLab is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* HeuristicLab is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with HeuristicLab. If not, see .
*/
#endregion
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using HeuristicLab.Core;
using HeuristicLab.Operators;
using HeuristicLab.Random;
using HeuristicLab.Data;
using HeuristicLab.Selection;
namespace HeuristicLab.GP {
public class OnePointShaker : DelegatingOperator {
public override string Description {
get { return "Selects a random node of all tree-nodes that have a '"+FunctionBase.MANIPULATION+"' variable defined and manipulates the selected node."; }
}
public OnePointShaker()
: base() {
AddVariableInfo(new VariableInfo("OperatorLibrary", "Operator library that defines mutation operations for operators", typeof(GPOperatorLibrary), VariableKind.In));
AddVariableInfo(new VariableInfo("Random", "A random generator (uniform)", typeof(MersenneTwister), VariableKind.In));
AddVariableInfo(new VariableInfo("ShakingFactor", "Factor that determines the force of the shaking operation", typeof(DoubleData), VariableKind.In));
AddVariableInfo(new VariableInfo("FunctionTree", "The function tree that should be mutated", typeof(IFunctionTree), VariableKind.In | VariableKind.Out));
}
public override IOperation Apply(IScope scope) {
GPOperatorLibrary library = GetVariableValue("OperatorLibrary", scope, true);
IFunctionTree tree = GetVariableValue("FunctionTree", scope, false);
MersenneTwister mt = GetVariableValue("Random", scope, true);
TreeGardener gardener = new TreeGardener(mt, library);
// get all nodes for which a manipulation is defined
var parametricBranches = gardener.GetAllSubTrees(tree).Where(branch => branch.Function.GetVariable(FunctionBase.MANIPULATION) != null);
IFunctionTree selectedBranch = parametricBranches.ElementAt(mt.Next(parametricBranches.Count()));
IOperator mutation = (IOperator)selectedBranch.Function.GetVariable(FunctionBase.MANIPULATION).Value;
CompositeOperation next = new CompositeOperation();
// store all local variables into a temporary scope
Scope tempScope = new Scope("Temp. manipulation scope");
foreach(IVariable variable in selectedBranch.LocalVariables) {
tempScope.AddVariable(variable);
}
// save the exising sub-scops in a backup scope
Scope backupScope = new Scope("backup");
foreach (Scope subScope in scope.SubScopes) {
backupScope.AddSubScope(subScope);
}
// add the new sub-scopes
scope.AddSubScope(tempScope);
scope.AddSubScope(backupScope);
// the next operation should first manipulate and then restore the sub-scopes from the backup scope
next.AddOperation(new AtomicOperation(mutation, tempScope));
next.AddOperation(new AtomicOperation(new RightReducer(), scope));
return next;
}
}
}