00001 #ifndef FrequentFilter_CPP
00002 #define FrequentFilter_CPP
00003
00008 #include "common.hpp"
00009 #include <vector>
00010
00011
00017 template <class IT_R>
00018 class FrequentFilter
00019 {
00020 public:
00021 FrequentFilter<IT_R>(IT_R& it_r):it_r(it_r){}
00022
00028 void findFrequentItems(
00029 std::vector< std::pair<counter_t, item_t> >& freq_items_with_counters,
00030 counter_t& nr_of_transactions, counter_t& min_supp,
00031 bool relative=false, double relminsupp=0.0);
00032 private:
00033 IT_R& it_r;
00034
00035
00036 };
00045 template <class IT_R> void FrequentFilter<IT_R>::findFrequentItems(
00046 std::vector< std::pair<counter_t, item_t> >& freq_items_with_counters,
00047 counter_t& nr_of_transactions, counter_t& min_supp,
00048 bool relative, double relminsupp)
00049 {
00050 freq_items_with_counters.clear();
00051 nr_of_transactions = 0;
00052 it_r.rewind();
00053
00054 std::vector<item_t> transaction;
00055 std::vector< counter_t > temp_counter_vector;
00056
00058 std::vector<item_t>::iterator it_transaction;
00059 while( it_r.nextTransactionBIS( transaction ) )
00060 {
00061 if( !transaction.empty() )
00062 {
00063 nr_of_transactions++;
00064 for( it_transaction = transaction.begin();
00065 it_transaction != transaction.end(); ++it_transaction )
00066 {
00067 if( *it_transaction + 1 > temp_counter_vector.size() )
00068 temp_counter_vector.resize( *it_transaction + 1, 0 );
00069 ++temp_counter_vector[*it_transaction];
00070 }
00071 }
00072 }
00073 it_r.setLargestItem( temp_counter_vector.size() - 1 );
00074
00075 if(relative)
00076 min_supp = static_cast<unsigned int>(relminsupp * nr_of_transactions);
00078 for( std::vector< counter_t >::size_type index = 0;
00079 index < temp_counter_vector.size(); ++index )
00080 if(temp_counter_vector[index] >= min_supp)
00081 {
00082 std::pair<counter_t, item_t> temp_pair(temp_counter_vector[index],index);
00083 freq_items_with_counters.push_back(temp_pair);
00084 }
00085 }
00086
00087 #endif
