G4mpi Namespace Reference

Typedefs
typedef unsigned int	rank_t
typedef std::pair< rank_t, rank_t >	couple_t
typedef std::map< int, std::vector< couple_t > >	commMap_t
typedef std::function< void(std::function< void(unsigned int)>, std::function< void(unsigned int)>, std::function< void(void)>, unsigned int, unsigned int)>	mergerHandler_t

Functions
commMap_t	buildCommunicationMap (std::vector< rank_t > &input)
void	Merge (std::function< void(unsigned int)> senderF, std::function< void(unsigned int)> receiverF, std::function< void(void)> barrierF, unsigned int commSize, unsigned int myrank)

Typedef Documentation

rank_t

typedef unsigned int G4mpi::rank_t

Definition at line 45 of file G4MPIutils.hh.

couple_t

typedef std::pair<rank_t,rank_t> G4mpi::couple_t

Definition at line 47 of file G4MPIutils.hh.

commMap_t

typedef std::map<int,std::vector<couple_t> > G4mpi::commMap_t

Definition at line 50 of file G4MPIutils.hh.

mergerHandler_t

typedef std::function<void(std::function<void(unsigned int)>, std::function<void(unsigned int)>, std::function<void(void)>, unsigned int, unsigned int)> G4mpi::mergerHandler_t

Definition at line 93 of file G4MPIutils.hh.

Function Documentation

buildCommunicationMap()

commMap_t G4mpi::buildCommunicationMap

(

std::vector< rank_t > &

input

)

Merge()

void G4mpi::Merge	(	std::function< void(unsigned int)>	senderF,
		std::function< void(unsigned int)>	receiverF,
		std::function< void(void)>	barrierF,
		unsigned int	commSize,
		unsigned int	myrank
	)

Definition at line 161 of file G4MPIutils.cc.

                                                         {
      //Optimize communications between ranks
      std::vector<G4mpi::rank_t> ranks(commSize);
      std::iota(ranks.begin(),ranks.end(),0); //{0,1,2,3,...}
      auto comms = G4mpi::buildCommunicationMap(ranks);
      //Loop on cycles of communications
      for ( const auto& cycle : comms ) {
          //Each cycle is a set of communications between ranks, it is guarantted that
          //each rank participate in one and only one communication for each cycle
         for (const auto& pattern : cycle.second ) {
             //pattern is a couple: sender,receiver
             if ( myrank == pattern.first ) {
                 //Send to destination
                 senderF(pattern.second);
             }
             else if ( myrank == pattern.second ) {
                 //Receive from source
                 receiverF(pattern.first);
             }
         }
         //Important: Wait for this cycle to end before going to the next, even if this rank
         //did not do anything
          //This is needed to be sure that the redcutions are done correctly
         barrierF();
    }
}