source: trunk/yat/statistics/euclidean_vector_distance.h @ 937

#ifndef theplu_yat_statistics_euclidean_vector_distance_h
#define theplu_yat_statistics_euclidean_vector_distance_h

// $Id: euclidean_vector_distance.h 937 2007-10-05 23:11:18Z peter $

#include "AveragerPair.h"
#include "AveragerPairWeighted.h"
#include "vector_distance.h"
#include "yat/utility/iterator_traits.h"

#include <cmath>

namespace theplu {
namespace yat {

namespace statistics {

  ///
  /// Provides a "label" for
  /// the Euclidean distance measure.
  ///
  struct euclidean_vector_distance_tag 
    : public vector_distance_tag
  {
    typedef euclidean_vector_distance_tag distance;
  };


  ///
  /// implementation for distances between vectors
  /// (containers with random access iterators) using a Euclidean
  /// distance measure and iterators to unweighted containers.
  /// 
  template <typename Iter1, typename Iter2>
  double vector_distance(Iter1 beg1,Iter1 end1, Iter2 beg2,
                         const euclidean_vector_distance_tag& disttype,
                         utility::unweighted_type)
  {
    AveragerPair ap;
    add(ap,beg1,end1,beg2);
    return sqrt(ap.sum_squared_deviation());
  }
  

  ///
  /// implementation for distances between vectors
  /// (containers with random access iterators) using a Euclidean
  /// distance measure and iterators to weighted containers.
  /// 
  template <typename Iter1, typename Iter2>
  double vector_distance(Iter1 beg1, Iter1 end1, Iter2 beg2,
                         const euclidean_vector_distance_tag& disttype,
                         utility::weighted_type)
  {
    AveragerPairWeighted ap;
    add(ap,beg1,end1,beg2);
    return sqrt((beg2-beg1)*ap.msd());
  }

  
}}} // of namespace statistics, yat, and theplu
    
#endif