JTRIGGER::reverse_clusterize Struct Reference

Anonymous structure for reverse clustering of hits. More...

#include <JAlgorithm.hh>

Public Member Functions
template<class JHitIterator_t , class JMatch_t >
JHitIterator_t	operator() (JHitIterator_t __begin, JHitIterator_t __end, const JMatch_t &match) const
	Partition data according given binary match operator. More...

Private Member Functions
template<class JHitIterator_t , class JMatch_t >
JHitIterator_t	operator() (JHitIterator_t buffer, const int N, const JMatch_t &match, std::random_access_iterator_tag tag) const
	Implementation of method reverse_clusterize for random access iterators. More...

Private Attributes
std::vector< int >	count

Detailed Description

Anonymous structure for reverse clustering of hits.

Definition at line 188 of file JAlgorithm.hh.

Member Function Documentation

template<class JHitIterator_t , class JMatch_t >

JHitIterator_t JTRIGGER::reverse_clusterize::operator() ( JHitIterator_t  __begin, JHitIterator_t  __end, const JMatch_t &  match  ) const

inline

Partition data according given binary match operator.

The underlying algorithm is known in literature as reverse 'clique'. The result is (likely to be) the maximal sub-set with all elements matched to each other. The complexity is quadratic, i.e. at most (number of elements x number of elements) operations. The algorithm will sort the data such that all clusterized hits are at the front. The return value points the first non clusterized hit.

The hit iterator refers to a data structure which should conform with the match operator.

Parameters

__begin	begin of data
__end	end of data
match	binary match operator

Returns

end of data

Definition at line 207 of file JAlgorithm.hh.

    {
      return (*this)(__begin,  std::distance(__begin,__end), match, typename std::iterator_traits<JHitIterator_t>::iterator_category());
    }

template<class JHitIterator_t , class JMatch_t >

JHitIterator_t JTRIGGER::reverse_clusterize::operator() ( JHitIterator_t  buffer, const int  N, const JMatch_t &  match, std::random_access_iterator_tag  tag  ) const

inlineprivate

Implementation of method reverse_clusterize for random access iterators.

Parameters

buffer	pointer to data
N	number of hits
match	binary match operator
tag	iterator tag

Returns

pointer to end of data

Definition at line 225 of file JAlgorithm.hh.

    {
      using namespace std;

      if (N != 0) {

        int i, j;

        // Determine number of associated hits for each hit.
    
        count.resize(N);

        for (vector<int>::iterator __i = count.begin(); __i != count.end(); ++__i) {
          *__i = 1;                        // Assume always a match with itself.
        }

        for (i = 0; i != N; ++i) {
          for (j = 0; j != i; ++j) {
            if (match(buffer[i], buffer[j])) {
              ++count[i];
              ++count[j];
            }
          }
        }

        // Keep hit with the largest number of associated hits.
        // This procedure stops when the number of associated hits is equal to one.
 
        for (int n = 0; ; ++n) {

          j = n;
      
          for (i = j; ++i != N; ) {
            if (count[i] > count[j]) {
              j = i;
            }
          }
      
          // Ready?

          if (count[j] == 1) {
            return buffer + n;
          }

          // Swap the selected hit to begin.

          swap(buffer[j], buffer[n]);
          swap(count [j], count [n]);

          // Decrease number of associated hits for each associated hit.

          for (i = n; ++i != N; ) {
            if (match(buffer[i], buffer[n])) {
              --count[i];
              --count[n];
            }
          }
        }
      }

      return buffer;
    }

Member Data Documentation

std::vector<int> JTRIGGER::reverse_clusterize::count

mutableprivate

Definition at line 292 of file JAlgorithm.hh.

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The documentation for this struct was generated from the following file:

• JAlgorithm.hh