extendabledata.cpp

MultiBoost 是c++实现的多类adaboost酸法。与传统的adaboost算法主要解决二类分类问题不同

/*
* This file is part of MultiBoost, a multi-class 
* AdaBoost learner/classifier
*
* Copyright (C) 2005-2006 Norman Casagrande
* For informations write to [e-mail]
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*
*/

#include "ExtendableData.h"

#include "Defaults.h" // for STABLE_SORT declaration
#include "Utils/Utils.h" // for comparePairOnSecond
#include <algorithm> // for sort

// ------------------------------------------------------------------------
namespace MultiBoost {

void ExtendableData::addColumn(const vector<double>& newColumnVector)
{
   // increment the number of columns for the stored data 
   ++_numColumns;
   _sortedData.resize(_numColumns);

   //////////////////////////////////////////////////////////////////////////
   // Fill the new column of the sorted data vector.
   // The data is stored column-wise. The pair represents the index 
   // of the example with the value.
   column& newColumn = _sortedData[_numColumns-1]; 
   newColumn.reserve(_numExamples);
   for (int i = 0; i < _numExamples; ++i)
       newColumn.push_back( make_pair(i, newColumnVector[i]) );
   
   //////////////////////////////////////////////////////////////////////////
   // Now sort the new column.  todo: for certain kind of features (2-valued or
   // 3-valued) sorting could be much more efficient with bucket sort, I might
   // want to signal it in a parameter and change the sorting action
   // accordingly.

#if STABLE_SORT
   stable_sort( newColumn.begin(), newColumn.end(), 
		nor_utils::comparePairOnSecond< int, double, less<double> > );
#else
   sort( newColumn.begin(), newColumn.end(), 
            nor_utils::comparePairOnSecond< int, double, less<double> > );
#endif
}

// ------------------------------------------------------------------------

} // end of namespace MultiBoost