lib_mpi_helper.h

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* Multiscale Universal Interface Code Coupling Library                       *
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#ifndef LIB_MPI_HELPER_H_
#define LIB_MPI_HELPER_H_
 
#include <mpi.h>
 
namespace mui {
 
namespace mpi {
 
template<typename T>
inline MPI_Datatype mpi_type( T              const& t );
inline MPI_Datatype mpi_type( int            const &t ) { return MPI_INT; }
inline MPI_Datatype mpi_type( long           const &t ) { return MPI_LONG; }
inline MPI_Datatype mpi_type( unsigned long  const &t ) { return MPI_UNSIGNED_LONG; }
inline MPI_Datatype mpi_type( long long      const &t ) { return MPI_LONG_LONG; }
inline MPI_Datatype mpi_type( float          const &t ) { return MPI_FLOAT; }
inline MPI_Datatype mpi_type( double         const &t ) { return MPI_DOUBLE; }
inline MPI_Datatype mpi_type( char           const &t ) { return MPI_CHAR; }
inline MPI_Datatype mpi_type( short          const &t ) { return MPI_SHORT; }
inline MPI_Datatype mpi_type( unsigned short const &t ) { return MPI_UNSIGNED_SHORT; }
 
template<typename T> inline std::vector<T> gather( T t, MPI_Comm comm ) {
    int size, rank;
    MPI_Comm_size( comm, &size );
    MPI_Comm_rank( comm, &rank );
    std::vector<T> v;
    if ( rank == 0 ) v.resize( size );
    MPI_Gather( &t, 1, mpi_type(t), v.data(), 1, mpi_type(t), 0, comm );
    return v;
}
 
}
 
}
 
#endif /* LIB_MPI_HELPER_H_ */