medmean.hpp

/* medmean.hpp */
/* $Id: medmean.hpp,v 1.4 2008/08/11 18:33:56 biburath Exp $ */
#ifndef __medmean_hpp
#define __medmean_hpp

#include <algorithm>

#include <iostream>

namespace median
{
  

  template<typename T, typename BadnessT>
  struct stl_compare
  {
    stl_compare(const BadnessT &q):badness(q)
    {
    }
  
    bool operator()(const T &a, const T &b) const
    {
      return badness(a)>badness(b);
    }
    BadnessT badness;
  };


  template<typename T, typename ContainerT, typename BadnessT>
  ContainerT
  filter(const ContainerT &OldSet, double rejection )
  {
  
    ContainerT Set=OldSet;
  

    //1. sorting
    {
      BadnessT bad(Set);
      stl_compare<T,BadnessT> comp(bad);
      std::sort(Set.begin(), Set.end(), comp);
    }

   
    //2. reducing
    double price=1.0/(double)Set.size();
    for(double p=1; p>=(1-rejection); p-=price){

      ContainerT S1=Set;
      S1.erase(S1.begin()); //S1 is Set without first element
    
      ContainerT S2=Set;
      S2.erase(--S2.end()); //S2 is Set without last element

      BadnessT
    B0=BadnessT(Set),
    B1=BadnessT(S1),
    B2=BadnessT(S2);

      if( B1() > B0() && B2() > B0() )
    break;
    
      if( B1() - B0() < B2() - B0() )
    Set=S1;
      else
    Set=S2;
    }

    return Set;
       
  }





};



#endif /* medmean.hpp */