parallel/mpihelper.hh File Reference

Helpers for dealing with MPI. More...

#include <cassert>
#include "collectivecommunication.hh"
#include "mpi.h"
#include "mpicollectivecommunication.hh"
#include <dune/common/stdstreams.hh>
#include <dune/common/visibility.hh>

Go to the source code of this file.

Classes
class	Dune::FakeMPIHelper
	A fake mpi helper. More...
class	Dune::MPIHelper
	A real mpi helper.This helper should be used for parallel programs. More...

Namespaces
	Dune
	Dune namespace.

Detailed Description

Helpers for dealing with MPI.

Basically there are two helpers available:

FakeMPIHelper

A class adhering to the interface of MPIHelper that does not need MPI at all. This can be used to create a sequential program even if MPI is used to compile it.

MPIHelper

A real MPI helper. When the singleton gets instantiated MPI_Init will be called and before the program exits MPI_Finalize will be called.

Example of who to use these classes:

A program that is parallel if compiled with MPI and sequential otherwise:

int main(int argc, char** argv){
   typedef Dune::MPIHelper MPIHelper;
   MPIHelper::instance(argc, argv);
   typename MPIHelper::MPICommunicator world =
     MPIHelper::getCommunicator();
   ...

If one wants to have sequential program even if the code is compiled with mpi then one simply has to exchange the typedef with

typedef Dune::MPIHelper FakeMPIHelper; 

.

For checking whether we really use MPI or just fake please use MPIHelper::isFake (this is also possible at compile time!)