send_recv_toroidal.hpp

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#ifndef SEND_RECV_TOROIDAL_HPP
#define SEND_RECV_TOROIDAL_HPP

#include "domain_decomposition.hpp"
#ifdef USE_MPI
// General template declaration, with an undefined implementation to cause a compile-time error if not specialized correctly
template<typename T>
struct MPIDataType;

// Template specialization for double
template<>
struct MPIDataType<double> {
    static MPI_Datatype value() { return MPI_DOUBLE; }
};

// Template specialization for int
template<>
struct MPIDataType<int> {
    static MPI_Datatype value() { return MPI_INT; }
};

template<typename T>
void send_to_neighbor_plane(const MyMPI& mpi, const T& source_view, const T& dest_view, bool send_right){
    int n_ranks = mpi.n_intpl_ranks;
    int this_rank = mpi.my_intpl_rank;
    int source_dist = send_right ? -1 : 1; // If sending to the right, the source is the intpl rank one less
    int source_rank = positive_modulo(this_rank-source_dist, n_ranks);
    int dest_rank = positive_modulo(this_rank+source_dist, n_ranks);
    int isendtag = this_rank;
    int irecvtag = source_rank;
    MPI_Datatype datatype = MPIDataType<typename T::value_type>::value();
    MPI_Sendrecv(source_view.data(), source_view.size(), datatype,dest_rank,  isendtag,
                 dest_view.data(),   dest_view.size(),   datatype,source_rank,irecvtag,
                 mpi.intpl_comm,MPI_STATUS_IGNORE);
}

template<typename T>
void send_right(const MyMPI& mpi, const T& source_view, const T& dest_view){
    send_to_neighbor_plane(mpi, source_view, dest_view, true);
}

template<typename T>
void send_left(const MyMPI& mpi, const T& source_view, const T& dest_view){
    send_to_neighbor_plane(mpi, source_view, dest_view, false);
}

#endif

#endif