khanat-opennel-code/code/ryzom/tools/assoc_mem/tree.cpp

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// Ryzom - MMORPG Framework <http://dev.ryzom.com/projects/ryzom/>
// Copyright (C) 2010 Winch Gate Property Limited
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// This program 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include <valarray>
#include <map>
#include <stdio.h>
#include <iostream>
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#include <algorithm>
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#include "tree.h"
#include "cond_node.h"
#include "result_node.h"
CTree::CTree()
{
_RootNode = NULL;
}
CTree::~CTree()
{
if ( _RootNode != NULL )
delete _RootNode;
}
void CTree::setKey(int key)
{
_Key = key;
}
int CTree::getKey()
{
return _Key;
}
bool CTree::getOutput(CRecord *input)
{
if ( _RootNode != NULL )
return _RootNode->propagRecord( input );
else
return false;
}
int CTree::getNbRecords(std::vector<CRecord *> &records,int key, IValue *value) //
{
int nb = 0;
std::vector<CRecord *>::iterator it_r = records.begin();
while ( it_r != records.end() )
{
if ( *((**it_r)[key]) == value )
nb++;
it_r++;
}
return nb;
}
double CTree::log2(double val) const
{
return (log(val) / log(2.0));
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}
double CTree::entropy(double a, double b) const
{
double p1;
double p2;
if ( a > 0 )
p1 = a * log2(a);
else
p1 = 0;
if ( b > 0 )
p2 = b * log2(b);
else
p2 = 0;
return ( p1 + p2 ) * -1;
}
double CTree::entropy(std::vector<double> &p) const
{
double result = 0;
std::vector<double>::iterator it_p = p.begin();
while ( it_p != p.end() )
{
double val = *it_p;
if ( val > 0 )
result = result + val * log2( val );
it_p++;
}
return result * -1;
}
double CTree::gain(std::vector<CRecord *> &records, int attrib, CField *field)
{
int nb_values = (int)field->getPossibleValues().size();
int nb_records = (int)records.size();
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CValue<bool> bool_true(true);
double nb_key_true = getNbRecords(records, _Key, &bool_true );
double nb_key_false = nb_records - nb_key_true;
double entropy_records = entropy( nb_key_true / nb_records, nb_key_false / nb_records );
double gain = entropy_records;
int i;
for ( i = 0; i < nb_values; i++ )
{
IValue *val = field->getPossibleValues()[i];
int nb_records_val, nb_records_notval;
splitRecords(records, attrib, val, nb_records_val, nb_records_notval );
int nb_records_val_key, nb_records_val_notkey;
splitRecords(records, attrib, val, true, nb_records_val_key, nb_records_val_notkey );
double entropy_val = entropy( ((double)nb_records_val_key) / ((double)nb_records_val), ((double)nb_records_val_notkey) / ((double)nb_records_val) );
gain = gain - ( ( (double)nb_records_val ) / ( (double) nb_records ) * entropy_val );
}
return gain;
}
std::vector<std::pair<double,int> > CTree::getSortedFields( std::vector<int> &attributes, std::vector<CRecord *> &records, std::vector<CField *> &fields )
{
std::vector<std::pair<double,int> > attribs;
if ( ! records.empty() )
{
std::vector<int>::iterator it_a = attributes.begin();
while ( it_a != attributes.end() )
{
if ( (*it_a) != _Key )
attribs.push_back( std::pair<double,int>( gain(records, (*it_a), fields[*it_a] ) , (*it_a) ) );
it_a++;
}
}
// Sorts the records by gain
std::sort(attribs.begin(), attribs.end(), greater() );
std::vector<std::pair<double,int> >::iterator it_f = attribs.begin();
std::cout << "Attributes(gain) :" << std::endl;
while ( it_f != attribs.end() )
{
std::cout << " " << fields[ (*it_f).second ]->getName() << " (" << (*it_f).first << ") " << std::endl;
it_f++;
}
std::cout << std::endl;
return attribs;
}
// Looks for the attrib with the most gain
int CTree::getBestAttrib( std::vector<int> &attributes, std::vector<CRecord *> &records, std::vector<CField *> &fields )
{
double tmp_gain;
double max_gain = 0;
int best_attrib = -1;
std::cout << "Attributes(gain) :" << std::endl;
if ( ! records.empty() )
{
std::vector<int>::iterator it_a = attributes.begin();
while ( it_a != attributes.end() )
{
if ( (*it_a) != _Key )
{
tmp_gain = gain( records, *it_a, fields[ *it_a ] );
std::cout << " " << fields[ *it_a ]->getName() << " (" << tmp_gain << ") " << std::endl;
if ( tmp_gain >= max_gain )
{
max_gain = tmp_gain;
best_attrib = *it_a;
}
}
it_a++;
}
}
return best_attrib;
}
void CTree::rebuild(std::vector<CRecord *> &records, std::vector<CField *> &fields)
{
std::vector<int> left_fields;
CRecord *first = *records.begin();
for (int i = 0; i < first->size(); i++ )
if ( i != _Key )
left_fields.push_back( i );
_RootNode = ID3( left_fields, records, fields );
}
float CTree::findNumKeyValue(std::vector<CRecord *> &records, int key)
{
float sum_true = 0;
float nb_true = 0;
float sum_false = 0;
float nb_false = 0;
std::vector<CRecord *>::iterator it_r = records.begin();
while ( it_r != records.end() )
{
bool result = ((CValue<bool> *)(**it_r)[ _Key ])->getValue();
if ( result == true )
{
sum_true += ((CValue<int> *)(**it_r)[ key ])->getValue();
nb_true ++;
}
else
{
sum_false += ((CValue<int> *)(**it_r)[ key ])->getValue();
nb_false ++;
}
it_r++;
}
return ( sum_true / nb_true + sum_false / nb_false ) / 2;
}
std::string CTree::getDebugString(std::vector<CRecord *> &records, std::vector<CField *> &fields)
{
std::string output;
output += "CTree KEY = ";
output += fields[ _Key ]->getName();
return output;
}
INode *CTree::ID3(std::vector<int> &attributes, std::vector<CRecord *> &records, std::vector<CField *> &fields)
{
if ( records.empty() )
{
return new CResultNode( false );
}
else
{
// If there is no attribute left and the records don't have the same key value,
// returns a result node with the most frequent key value
if ( attributes.empty() )
{
int nb_key_true;
int nb_key_false;
splitRecords( records, _Key , nb_key_true, nb_key_false );
if ( nb_key_true > nb_key_false )
return new CResultNode( true );
else
return new CResultNode( false );
}
// Tests if all records have the same key value, if so returns a result node with this key value.
int nb_records = (int)records.size();
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int nb_key_true;
int nb_key_false;
splitRecords( records, _Key , nb_key_true, nb_key_false );
if ( nb_key_true == nb_records )
return new CResultNode( true );
if ( nb_key_false == nb_records )
return new CResultNode( false );
// Gets the attribute with the most gain for the current record set,
// and recursively builds the subnodes corresponding to each
// possible value for this attribute.
int best_gain_attrib = getBestAttrib( attributes, records, fields );
std::vector< std::vector<CRecord *> > sorted_records;
splitRecords( records, best_gain_attrib, fields, sorted_records ); // classifies the records depending on the value of the best gain attribute
std::vector<int> new_attribs;
for ( int i = 0; i < (int) attributes.size(); i++ ) // Creates a new attributes list from the current attributes list with the best gain attribute removed
if ( attributes[i] != best_gain_attrib )
new_attribs.push_back( attributes[i] );
ICondNode *root_node = fields[best_gain_attrib]->createNode(_Key, best_gain_attrib, records);
std::vector< std::vector<CRecord *> >::iterator it = sorted_records.begin(); // Constructs subnodes recursively
while ( it != sorted_records.end() )
{
root_node->addNode( ID3( new_attribs, *it, fields ) );
it++;
}
return root_node;
}
}
std::vector<CRecord *> CTree::getRecords(std::vector<CRecord *> &records, int attrib, bool value)
{
std::vector<CRecord *> result;
std::vector<CRecord *>::iterator it_r = records.begin();
while ( it_r != records.end() )
{
if ( ((CValue<bool> *)(**it_r)[attrib])->getValue() == value )
result.push_back( *it_r );
it_r++;
}
return result;
}
void CTree::splitRecords(std::vector<CRecord *> &records, int attrib, int &true_records, int &false_records) //
{
true_records = 0;
false_records = 0;
std::vector<CRecord *>::iterator it_r = records.begin();
while ( it_r != records.end() )
{
if ( ((CValue<bool> *)(**it_r)[attrib])->getValue() == true )
true_records++;
else
false_records++;
it_r++;
}
}
void CTree::splitRecords(std::vector<CRecord *> &records, int attrib, IValue *val, int &true_records, int &false_records) //
{
true_records = 0;
false_records = 0;
std::vector<CRecord *>::iterator it_r = records.begin();
while ( it_r != records.end() )
{
const IValue *left_val = (**it_r)[ attrib ];
if ( ( *left_val ) == val )
true_records++;
else
false_records++;
it_r++;
}
}
// count records with a certain value for an attrib and true or false for the key attrib
void CTree::splitRecords(std::vector<CRecord *> &records, int attrib, IValue *val, bool key, int &true_records, int &false_records) //
{
true_records = 0;
false_records = 0;
std::vector<CRecord *>::iterator it_r = records.begin();
while ( it_r != records.end() )
{
if ( (* ( (**it_r)[attrib] ) ) == val )
{
if ( ( (CValue<bool> *) (**it_r)[ _Key ] )->getValue() == key )
true_records++;
else
false_records++;
}
it_r++;
}
}
// Sorts records according to the possibles values for an attribute.
void CTree::splitRecords( std::vector<CRecord *> &records, int attrib, std::vector<CField *> &fields, std::vector< std::vector<CRecord *> > &result) //
{
if ( result.size() < fields[attrib]->getPossibleValues().size() )
{
int nb_missing = (int)(fields[attrib]->getPossibleValues().size() - result.size());
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for (int i = 0; i <= nb_missing; i++ )
{
result.push_back( std::vector<CRecord *>() );
}
}
std::vector<CRecord *>::iterator it_r = records.begin();
while ( it_r != records.end() )
{
std::vector<IValue *>::const_iterator it_vp = fields[attrib]->getPossibleValues().begin();
std::vector< std::vector<CRecord *> >::iterator it = result.begin();
int id_val = 0;
while ( it_vp != fields[attrib]->getPossibleValues().end() )
{
const IValue *left_value = (**it_r)[attrib];
IValue *right_value = *it_vp;
if ( (*left_value) == right_value )
(*it).push_back( *it_r );
it_vp++;
it++;
}
it_r++;
}
}