OptFrame/Parallel/MapReduce++/MapMP/reducer.hpp

#ifndef REDUCER_HPP
#define REDUCER_HPP

template<class KeyA, class A, class KeyB, class B, class C>
class MapMP_Reducer : public Reducer<KeyA,A,KeyB,B,C>
{ 
public:
        MapMP_Reducer(MapReduce<KeyA,A,KeyB,B,C> * _mapReduce):mapReduce(_mapReduce){};
#ifndef MRI_USE_MULTIMAP
        virtual vector< pair<KeyB,C> > run( vector< pair<KeyB,B> > & _mapped) {
                multimap<KeyB,B> mapped;
                for (int i = 0 ; i < _mapped.size() ; i++) mapped.insert(_mapped[i]);
#else
        virtual vector< pair<KeyB,C> > run( multimap<KeyB,B> & mapped) {
#endif

                typename std::multimap<KeyB,B>::iterator it = mapped.begin();
                KeyB lastKey = (*it).first;
                vector< pair < KeyB,vector<B> > > toReduce(1, pair < KeyB,vector<B> >( lastKey , vector<B>() ) );
                for( ; it != mapped.end() ; ++it)
                {
                        if ((*it).first != lastKey) {
                                toReduce.push_back( pair< KeyB,vector<B> > ( (*it).first , vector<B>() ) ); 
                                lastKey = (*it).first;
                        }
                        toReduce.back().second.push_back( (*it).second );
                }

                vector< pair<KeyB,C> > reduced(toReduce.size());

                #pragma omp parallel for
                for ( int i = 0 ; i < toReduce.size() ; i++ ) {
                        reduced[i] = reduce( toReduce[i] ); // Reduce call
                }

                return reduced;
        };
        virtual pair<KeyB,C> reduce( pair<KeyB, vector<B> > ) = 0 ;
protected:
        MapReduce<KeyA,A,KeyB,B,C> * mapReduce;
};

class MapMP_StrReducer : public MapMP_Reducer<string,string,string,string,string> 
{
public:
        MapMP_StrReducer(MapReduce<string,string,string,string,string> * _mapReduce)
                :MapMP_Reducer<string,string,string,string,string>(_mapReduce){};       
};

#endif /* REDUCER_HPP */