NICE_VisLearning/features/simplefeatures/CodebookRandomForest.cpp

/** 
* @file CodebookRandomForest.cpp
* @brief feature CodebookRandomForest
* @author Erik Rodner
* @date 02/15/2008

*/

#include <queue>
#include <iostream>

#include "CodebookRandomForest.h"

using namespace OBJREC;

using namespace std;
using namespace NICE;

CodebookRandomForest::CodebookRandomForest( int maxDepth, int restrictedCodebookSize )
{
	this->clusterforest = NULL;
    this->maxDepth = maxDepth;
    this->restrictedCodebookSize = restrictedCodebookSize;
}

CodebookRandomForest::CodebookRandomForest( FPCRandomForests *clusterforest,
    int maxDepth, int restrictedCodebookSize )
{
    this->clusterforest = clusterforest;
    this->maxDepth = maxDepth;
    this->restrictedCodebookSize = restrictedCodebookSize;
    buildLeafMap();
}

CodebookRandomForest::~CodebookRandomForest()
{
    if ( clusterforest != NULL )
        delete clusterforest;
}

void CodebookRandomForest::setClusterForest( FPCRandomForests *clusterforest)
{
	if(this->clusterforest != NULL)
		delete this->clusterforest;
	
	this->clusterforest = clusterforest;
	buildLeafMap();
}

void CodebookRandomForest::buildParentStructure ( DecisionNode *node, 
	map<DecisionNode *, DecisionNode *> & parentStructure )
{
    if ( node == NULL ) return;
    if ( node->left != NULL )
    {
		parentStructure.insert ( pair<DecisionNode *, DecisionNode *> ( node->left, node ) );
		buildParentStructure ( node->left, parentStructure );
    }
    if ( node->right != NULL )
    {
		parentStructure.insert ( pair<DecisionNode *, DecisionNode *> ( node->right, node ) );
		buildParentStructure ( node->right, parentStructure );
    }
}

void CodebookRandomForest::pruneForest ()
{
    map<DecisionNode *, pair<long, int> > index;
    clusterforest->indexDescendants( index );
    map<DecisionNode *, DecisionNode *> parentStructure;

    vector<DecisionTree *> & trees = clusterforest->getForestNonConst();

    for ( vector<DecisionTree *>::const_iterator i = trees.begin();
		i != trees.end(); i++ )
    {
		DecisionTree *tree = *i;
		parentStructure.insert ( pair<DecisionNode *, DecisionNode *> ( tree->getRoot(), NULL ) );
		buildParentStructure ( tree->getRoot(), parentStructure );
    }

    priority_queue< triplet<double, long, DecisionNode *> > lastLevelInnerNodes;

    long leafs = 0;
    for ( map<DecisionNode *, pair<long, int> >::const_iterator k = index.begin();
	    k != index.end(); k++ )
    {
		DecisionNode *node = k->first;
		if ( (!node->isLeaf()) && ((node->left->isLeaf())
			 || (node->right->isLeaf())) )
		{
			double mi = node->distribution.entropy() - ( 
			node->left->distribution.sum() * node->left->distribution.entropy() +
			node->right->distribution.sum() * node->right->distribution.entropy() )
			   / node->distribution.sum();
			lastLevelInnerNodes.push ( triplet<double, long, DecisionNode *> ( 
			- mi, k->second.first, node ) );
		}

		if ( node->isLeaf() ) leafs++;
    }

    set< DecisionNode * > deletedRoots;

	/*********************************************
	 * EVIL Pruning method                       *
	 *********************************************/
	set<DecisionNode *> deletedNodes;
    while ( (leafs > restrictedCodebookSize) && (lastLevelInnerNodes.size() > 0) )
    {
		const triplet<double, long, DecisionNode *> & nodemi = lastLevelInnerNodes.top();
		//double current_mi = -nodemi.first;
		//fprintf (stderr, "CodebookRandomForest: %d contract leaf with mutual information %f\n", leafs, current_mi );
		DecisionNode *node = nodemi.third;
		lastLevelInnerNodes.pop();

		assert ( node != NULL );

		DecisionNode *left = node->left;
		DecisionNode *right = node->right;
		//fprintf (stderr, "node: %ld, left: %ld, right: %ld\n", (long int)node, (long int)left,
		//    (long int)right ); 
		if ( (deletedNodes.find(node) != deletedNodes.end() ) || node->isLeaf() ) {
			// this is a tricky case...consider the subsequent contraction of
			// two childs of a node
			// After the first child is contracted, the node is added to lastLevelInnerNodes
			// If the second child is contracted, the node is still in the queue but
			// is now a leaf node.
			// A second problem exists if the parent node is contracted after the second
			// child but before the node. Therefore we introduced deletedNodes.
			continue;
		}

		#ifdef DEBUGPRUNING
		fprintf (stderr, "CodebookRandomForest: nodes remaining %ld (min:%d); current mi %f\n", 
			leafs, restrictedCodebookSize, current_mi );
		#endif
    
		assert ( parentStructure.find(node) != parentStructure.end() );
		DecisionNode *parent_node = parentStructure[node];
		//fprintf (stderr, "parent: %ld\n", (long int)parent_node );
		if ( parent_node == NULL )
		{
			#ifdef DEBUGPRUNING
			fprintf (stderr, "CodebookRandomForest: Deleting the root node !!!\n");
			#endif

			DecisionNode *newParent = NULL;
			if ( (left->isLeaf()) && (right->isLeaf()) )
			{
				//fprintf (stderr, "case (a)\n");
				delete ( node->f );
				node->f = NULL;
				delete left;
				delete right;
				deletedNodes.insert ( left );
				deletedNodes.insert ( right );
					
				node->left = NULL;
				node->right = NULL;
				newParent = node;
				leafs--;
			} else if ( left->isLeaf() ) {
				// case (b) left child is a leaf
				delete left;
				delete node;
				deletedNodes.insert ( node );
				deletedNodes.insert ( left );
				parentStructure[right] = parent_node;
				newParent = right;
				leafs--;
			} else if ( right->isLeaf() ) {
				// case (b) right child is a leaf
				delete right;
				delete node;
				deletedNodes.insert ( right );
				deletedNodes.insert ( left );

				parentStructure[left] = parent_node;
				newParent = left;
				leafs--;
			} else {
				fprintf (stderr, "UNKNOWN CASE !!\n");
				exit(-1);
			}
			for ( vector<DecisionTree *>::iterator i = trees.begin(); i != trees.end() ; i++ )
				if ( (*i)->getRoot() == node )
					(*i)->setRoot(newParent);    

			continue;
		}
		long int parent_index = index[parent_node].first;
		double mi = 0.0;
		bool nodeIsLeft = ( parent_node->left == node );
		DecisionNode *sibling = nodeIsLeft ? parent_node->right : parent_node->left;

		if ( (left == NULL) || (right == NULL) )
			fthrow(Exception, "There is a bug in this code: CodebookRandomForest (good luck!) bugid=1");

		if ( (left->isLeaf()) && (right->isLeaf()) )
		{

			/* ------------ case (a) left and right childs are leafs
					(p)                    (p)
			  (n)         (s)      ->  (n)     (s)  and add p to the last level nodes
			(l) (r)                                     */

			#ifdef DEBUGPRUNING
			fprintf (stderr, "case (a)\n");
			#endif

			delete ( node->f );
			node->f = NULL;
			delete left;
			deletedNodes.insert ( left );
			delete right;
			deletedNodes.insert ( right );
			node->left = NULL;
			node->right = NULL;
			leafs--;
			double ep = parent_node->distribution.entropy();
			double en = node->distribution.entropy();
			double es = sibling->distribution.entropy();
			double pn = node->distribution.sum();
			double ps = sibling->distribution.sum();
			mi = ep - ( pn * en + ps * es ) / (pn+ps);

			#ifdef DEBUGPRUNING
			fprintf (stderr, "ep %f en %f es %f pn %f ps %f\n", 
			ep, en, es, pn, ps );
			parent_node->distribution.store(cerr);
			node->distribution.store(cerr);
			sibling->distribution.store(cerr);
			
			fprintf (stderr, "add new pre-leaf %ld: mi %lf top %lf\n", (long int)parent_node, mi, 
				-lastLevelInnerNodes.top().first);
			#endif

			lastLevelInnerNodes.push ( triplet<double, long, DecisionNode *> (
				- mi, parent_index, parent_node ) );


		} else if ( left->isLeaf() ) {
			// --------------- case (b) left child is a leaf
		
			#ifdef DEBUGPRUNING
			fprintf (stderr, "case (b)\n");
			#endif

			if ( nodeIsLeft ) 
				parent_node->left = right;
			else
				parent_node->right = right;

			parentStructure[right] = parent_node;
			delete left;
			deletedNodes.insert ( left );
			delete node;
			deletedNodes.insert ( node );
			leafs--;

	
		} else if ( right->isLeaf() ) {
		
			// --------------- case (c) right child is a leaf
			
			#ifdef DEBUGPRUNING
			fprintf (stderr, "case (c)\n");
			#endif
			if ( nodeIsLeft ) 
				parent_node->left = left;
			else
				parent_node->right = left;
			
			delete right;
			deletedNodes.insert ( right );
			delete node;
			deletedNodes.insert ( node );
			parentStructure[left] = parent_node;
			leafs--;
		} else {
			fthrow(Exception, "There is a bug in this code: CodebookRandomForest (good luck!) bugid=2");
		}
    }

    for ( vector<DecisionTree *>::iterator i = trees.begin(); i != trees.end() ; )
    {
		if ( deletedRoots.find((*i)->getRoot()) != deletedRoots.end() )
		{
			delete (*i);
			trees.erase ( i );
		} else {
			i++;
		}
    }

    fprintf (stderr, "Final number of leafs: %ld (%d)\n", leafs, restrictedCodebookSize );
}

void CodebookRandomForest::buildLeafMap ()
{
    if ( restrictedCodebookSize > 0 ) {
		pruneForest ();
    }

    map<DecisionNode *, pair<long, int> > index;
    vector< pair<long, DecisionNode *> > index_reverse;
    clusterforest->indexDescendants ( index );

    leafMap.clear();
    for ( map<DecisionNode *, pair<long, int> >::const_iterator i = index.begin();
	    i != index.end(); i++ )
    {
		DecisionNode *node = i->first;
		int depth = i->second.second;
		long index = i->second.first;
		if ( ( (node->right == NULL) && (node->left == NULL) && (depth <= maxDepth) ) || ( depth == maxDepth ) )
			index_reverse.push_back ( pair<long, DecisionNode *> ( index, node ) );
	}

    sort ( index_reverse.begin(), index_reverse.end() );

    /*************************************
	Recover a kind of canonical node
	permutation
    **************************************/
    for ( vector< pair<long, DecisionNode *> >::const_iterator i = index_reverse.begin();
	    i != index_reverse.end(); i++ )
    {
		DecisionNode *node = i->second;
		leafMap.insert ( pair<DecisionNode *, int> ( node, leafMap.size() ) );
    }

    fprintf (stderr, "CSRandomForest::buildLeafMap: dimension = %d\n", (int)leafMap.size() );

    reinit ( leafMap.size() );
}


void CodebookRandomForest::copy ( const Codebook *codebook )
{
    fthrow(Exception, "CodebookRandomForest::not yet implemented !\n");
}

void CodebookRandomForest::vote ( const NICE::Vector & feature, int & codebookEntry, double & weight, double & distance ) const
{
    fthrow(Exception, "CodebookRandomForest::not supported, please use multi voting feature\n");
}

void CodebookRandomForest::vote ( const NICE::Vector & feature, NICE::Vector & histogram, 
		    int & codebookEntry, double & weight, double & distance ) const
{
    SparseVector votes;
    vote ( feature, votes );
    for ( SparseVector::const_iterator i = votes.begin(); 
		i != votes.end(); i++ )
    {
		int index = i->first;
		double val = i->second;
		histogram[index] += val;

		if ( i == votes.begin() )
		{
			codebookEntry = index;
			weight = val;
		}
    }
    distance = 0.0;
}

void CodebookRandomForest::vote ( const NICE::Vector & feature, NICE::SparseVector & votes ) const
{
    vector<DecisionNode *> leafNodes;
    NICE::Vector *x = new NICE::Vector ( feature );
    Example pe ( x );
    clusterforest->getLeafNodes ( pe, leafNodes, maxDepth );
    delete x;
    for ( vector<DecisionNode *>::const_iterator j = leafNodes.begin();
		j != leafNodes.end(); j++ )
    {
		map<DecisionNode *, int>::const_iterator k = leafMap.find ( *j );
		assert ( k != leafMap.end() );
		int leafindex = k->second;
		votes.insert ( votes.begin(), pair<int, double> ( leafindex, 1.0 ) );
    }

}

void CodebookRandomForest::voteAndClassify ( const NICE::Vector & feature, NICE::SparseVector & votes, FullVector & distribution ) const
{
    vector<DecisionNode *> leafNodes;
    NICE::Vector *x = new NICE::Vector ( feature );
    Example pe ( x );
    clusterforest->getLeafNodes ( pe, leafNodes, maxDepth );
    delete x;

    for ( vector<DecisionNode *>::const_iterator j = leafNodes.begin();
		j != leafNodes.end(); j++ )
    {
		map<DecisionNode *, int>::const_iterator k = leafMap.find ( *j );
		DecisionNode *node = *j;

		assert ( k != leafMap.end() );
		int leafindex = k->second;
		votes.insert ( votes.begin(), pair<int, double> ( leafindex, 1.0 ) );

		FullVector sDistribution ( node->distribution );
		sDistribution.normalize();
		if ( distribution.empty() )
			distribution = sDistribution;
		else
			distribution.add ( sDistribution );
    }

	distribution.normalize();
}

void CodebookRandomForest::add ( const Codebook *codebook )
{
    fthrow ( Exception, "CodebookRandomForest::not yet implemented !");
}
	
Codebook *CodebookRandomForest::clone () const
{
    return (new CodebookRandomForest(maxDepth, restrictedCodebookSize));
}

void CodebookRandomForest::clear ()
{
    if ( clusterforest != NULL )
        clusterforest->clear();
    Codebook::clear();
}

void CodebookRandomForest::restore ( istream & is, int format )
{
	if(this->clusterforest == NULL)
		this->clusterforest = new FPCRandomForests ();
    Codebook::restore(is, format);
    int maxClassNo = 0;
    is >> maxClassNo;
    clusterforest->setMaxClassNo( maxClassNo );
    clusterforest->restore ( is, format );
    buildLeafMap();
}

void CodebookRandomForest::store ( ostream & os, int format ) const
{
    Codebook::store ( os, format );
    os << endl;
    os << clusterforest->getMaxClassNo() << endl;
    clusterforest->store ( os, format );
    os << endl;
}