mpi_communicator.h

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#pragma once
 
#include <mpi.h>
 
namespace dg
{
template<class value_type>
static inline MPI_Datatype getMPIDataType(){ assert( false && "Type not supported!\n" ); return MPI_DOUBLE; }
template<>
inline MPI_Datatype getMPIDataType<double>(){ return MPI_DOUBLE;}
template<>
inline MPI_Datatype getMPIDataType<float>(){ return MPI_FLOAT;}
template<>
inline MPI_Datatype getMPIDataType<int>(){ return MPI_INT;}
template<>
inline MPI_Datatype getMPIDataType<bool>(){ return MPI_C_BOOL;}
template<>
inline MPI_Datatype getMPIDataType<unsigned>(){ return MPI_UNSIGNED;}
 
template< class LocalContainer>
struct aCommunicator
{
    using value_type = get_value_type<LocalContainer>;
 
    using container_type = LocalContainer; 
 
    LocalContainer allocate_buffer( )const{
        if( do_size() == 0 ) return LocalContainer();
        return do_make_buffer();
    }
 
    void global_gather( const value_type* values, LocalContainer& buffer)const
    {
        do_global_gather( values, buffer);
    }
 
    LocalContainer global_gather( const value_type* values) const
    {
        LocalContainer tmp = do_make_buffer();
        do_global_gather( values, tmp);
        return tmp;
    }
 
    void global_scatter_reduce( const LocalContainer& toScatter, value_type* values) const{
        do_global_scatter_reduce(toScatter, values);
    }
 
    unsigned buffer_size() const{return do_size();}
    unsigned local_size() const{return m_source_size;}
    bool isCommunicating() const{
        return do_isCommunicating();
    }
    MPI_Comm communicator() const{return do_communicator();}
    virtual aCommunicator* clone() const =0;
    virtual ~aCommunicator(){}
    protected:
    aCommunicator(unsigned local_size=0):m_source_size(local_size){}
    aCommunicator(const aCommunicator& src):m_source_size( src.m_source_size){ }
    aCommunicator& operator=(const aCommunicator& src){
        m_source_size = src.m_source_size;
        return *this;
    }
    void set_local_size( unsigned new_size){
        m_source_size = new_size;
    }
    private:
    unsigned m_source_size;
    virtual MPI_Comm do_communicator() const=0;
    virtual unsigned do_size() const=0;
    virtual LocalContainer do_make_buffer( )const=0;
    virtual void do_global_gather( const value_type* values, LocalContainer& gathered)const=0;
    virtual void do_global_scatter_reduce( const LocalContainer& toScatter, value_type* values) const=0;
    virtual bool do_isCommunicating( ) const {
        return true;
    }
};
 
 
 
 
 
}//namespace dg