BottomNI.h

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// -*- C++ -*-

// PLearn (A C++ Machine Learning Library)
// Copyright (C) 1998 Pascal Vincent
// Copyright (C) 1999,2000 Pascal Vincent, Yoshua Bengio and University of Montreal
//

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// 
//  1. Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
// 
//  2. Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
// 
//  3. The name of the authors may not be used to endorse or promote
//     products derived from this software without specific prior written
//     permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
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// This file is part of the PLearn library. For more information on the PLearn
// library, go to the PLearn Web site at www.plearn.org


 

/* *******************************************************      
   * $Id: BottomNI.h,v 1.4 2004/07/21 16:30:53 chrish42 Exp $
   * AUTHORS: Yoshua Bengio
   * This file is part of the PLearn library.
   ******************************************************* */


#ifndef BottomNI_INC
#define BottomNI_INC

#include <plearn/base/general.h>
#include "TMat.h"

namespace PLearn {
using namespace std;

  template <class T>
  class BottomNI
  {
  protected:
    int n_zeros; 
    int N;
    TVec< pair<T,int> > bottomn;
    pair<T,int>* bottomnptr; 
    pair<T,int>* maxpair;
  
  public:

    BottomNI()
    {}
    
    BottomNI(int the_N) { init(the_N); }

    void init(int the_N)
    {
      N = the_N;
      bottomn.resize(N); 
      bottomn.resize(0); 
      bottomnptr = bottomn.data(); 
      n_zeros=0;
    }

    void reset() { init(N); }

    void update(T value, int index)
    {
      int l=bottomn.length();
      if(value==0)
        n_zeros++;
      if(l<N)
        {
          bottomn.append( pair<T,int>(value,index) );
          if (l==0 || value>maxpair->first)
            maxpair = &bottomnptr[l];
        }
      else if(value<maxpair->first)
        {
          maxpair->first = value;
          maxpair->second = index;

          pair<T,int>* it = bottomnptr;
          int n = N;
          while(n--)
            {
              if(it->first>maxpair->first)
                maxpair = it;
              ++it;
            }
        }
    }

    int nZeros() const {return n_zeros;}

    void sort() 
    { std::sort(bottomnptr, bottomnptr+bottomn.length()); }

    const TVec< pair<T,int> >& getBottomN() { return bottomn; }
  };

} // end of namespace PLearn

#endif

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