TreeMutSubtree.cpp

#include "../ECF_base.h"
#include "Tree.h"
#include "TreeMutSubtree.h"
#include <stdio.h>
 
 
namespace Tree
{
 
void TreeMutSubtree::registerParameters(StateP state)
{
    myGenotype_->registerParameter(state, "mut.subtree", (voidP) new double(0), ECF::DOUBLE);
}
 
 
bool TreeMutSubtree::initialize(StateP state)
{
    voidP sptr = myGenotype_->getParameterValue(state, "mut.subtree");
    probability_ = *((double*)sptr.get());
    return true;
}
 
 
bool TreeMutSubtree::mutate(GenotypeP gene)
{
    Tree* tree = (Tree*) (gene.get());
 
    // try to select random node in tree which is not a terminal and which is not on maxDepth
    // this is a size-fair operator (depth condition)
    uint chosenNode;
    uint chosenNodeSubtreeSize;
    uint chosenNodeDepth;
    uint tries = 0;
    do {
        chosenNode = state_->getRandomizer()->getRandomInteger((int) tree->size());
        chosenNodeSubtreeSize = tree->at(chosenNode)->size_;
        chosenNodeDepth = tree->at(chosenNode)->depth_;
        tries++;
    } while((/*chosenNodeSubtreeSize == 1 || */chosenNodeDepth == tree->maxDepth_) && tries < 4);
 
    if(tries == 4) {
        ECF_LOG(state_, 5, "TreeMutSubtree not successful.");
        return false;
    }
 
    // first of all, make a copy of tree and clear the original
    Tree* copyTree = tree->copy();
    tree->clear();
 
    std::stringstream log;
    log << "TreeMutSubtree successful (";
 
    uint i = 0;
 
    // copy all nodes before chosen subtree to original
    for( ; i < chosenNode; i++) {
        NodeP node = static_cast<NodeP> (new Node(copyTree->at(i)->primitive_));
        tree->addNode(node);
    }
 
    log << "mutatedSubtree(at depth " << chosenNodeDepth << ") = ";
    for( ; i < chosenNode + chosenNodeSubtreeSize; i++) {
        // this node is an element of the chosen subtree
        log << copyTree->at(i)->primitive_->getName() << " ";
    }
 
    // generate new subtree with same primitives as original tree
    // maxDepth for that new tree is original tree->maxDepth_ - chosenNodeDepth
    Tree* newTree = tree->copy();
    newTree->clear();
    newTree->initMinDepth_ = 0;
    newTree->initMaxDepth_ = copyTree->maxDepth_ - chosenNodeDepth;
 
    if(state_->getRandomizer()->getRandomInteger(0, 1) % 2 == 0)
        newTree->fullBuild(copyTree->primitiveSet_);
    else
        newTree->growBuild(copyTree->primitiveSet_);
 
    log << ", newSubtree = ";
    // copy all nodes from newTree to tree
    for(uint j = 0; j < newTree->size(); j++) {
        NodeP node = static_cast<NodeP> (new Node(newTree->at(j)->primitive_));
        tree->addNode(node);
        log << node->primitive_->getName() << " ";
    }
    log << ")";
 
    // copy all nodes after chosen subtree to original
    for( ; i < copyTree->size(); i++) {
        NodeP node = static_cast<NodeP> (new Node(copyTree->at(i)->primitive_));
        tree->addNode(node);
    }
 
    tree->update();
    delete copyTree;
    delete newTree;
 
    ECF_LOG(state_, 5, log.str());
 
    return true;
}
 
}