source: trunk/yat/classifier/SVindex.h @ 706

#ifndef _theplu_yat_classifier_sv_index_ 
#define _theplu_yat_classifier_sv_index_ 

// $Id: SVindex.h 706 2006-12-19 08:59:19Z jari $

/*
  Copyright (C) The authors contributing to this file.

  This file is part of the yat library, http://lev.thep.lu.se/trac/yat

  The yat library 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 2 of the
  License, or (at your option) any later version.

  The yat 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
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  02111-1307, USA.
*/

#include "yat/utility/vector.h"

#include <cassert>
#include <vector>

namespace theplu {
namespace yat {
namespace classifier {  

#ifndef DOXYGEN_SHOULD_SKIP_THIS
  /// @internal Class keeping track of which samples are support vectors and
  /// not. The first nof_sv elements in the vector are indices of the
  /// support vectors
  ///
  class SVindex
  {

  public:
    //Default Contructor
    SVindex(); 

    // 
    SVindex(const size_t);

    // @return index_first
    inline size_t index_first(void) const { return index_first_; }

    // @return index_second
    inline size_t index_second(void) const { return index_second_; }

    // synch the object against alpha
    void init(const utility::vector& alpha, const double);

    // @return nof samples
    inline size_t size(void) const { return vec_.size(); }

    // @return nof support vectors
    inline size_t nof_sv(void) const { return nof_sv_; }

    // making first to an nsv. If already sv, nothing happens.
    void nsv_first(void);

    // making second to an nsv. If already sv, nothing happens.
    void nsv_second(void);   

    // randomizes the nsv part of vector and sets index_first to
    // nof_sv_ (the first nsv)
    void shuffle(void);

    // making first to a sv. If already sv, nothing happens.
    void sv_first(void);

    // making second to a sv. If already sv, nothing happens.
    void sv_second(void);

    //
    void update_first(const size_t);

    //
    void update_second(const size_t);

    // @return value_first
    inline size_t value_first(void) const { return value_first_; }

    // @return const ref value_second
    inline size_t value_second(void) const { return value_second_; }

    inline size_t operator()(size_t i) const { return vec_[i]; }

  private:
    size_t index_first_;
    size_t index_second_;
    size_t nof_sv_;
    std::vector<size_t> vec_;
    size_t value_first_; // vec_[index_first_] exists for fast access
    size_t value_second_; // vec_[index_second_] exists for fast access
    
  };
#endif /* DOXYGEN_SHOULD_SKIP_THIS */ 

}}} // of namespace classifier, yat, and theplu

#endif