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Grid/Grid_mpi.cc
Peter Boyle 98f14f1030 Fixing the Checkerboarding cshift.
Implemented "fake" communications in preparation for the leap to MPI.
2015-03-29 20:35:37 +01:00

86 lines
2.0 KiB
C++

#include "Grid.h"
#include <mpi.h>
namespace dpo {
// Should error check all MPI calls.
CartesianCommunicator::CartesianCommunicator(std::vector<int> &processors)
{
_ndimension = _processors.size();
std::vector<int> periodic(_ndimension,1);
_processors = processors;
_processor_coords.resize(_ndimension);
MPI_Cart_create(MPI_COMM_WORLD _ndimension,&_processors[0],&periodic[0],1,&communicator);
MPI_Comm_rank(communicator,&_processor);
MPI_Cart_coords(communicator,_processor,_ndimension,&_processor_coords[0]);
}
void CartesianCommunicator::GlobalSumF(float &f){
MPI_Allreduce(&f,&f,1,MPI_FLOAT,MPI_SUM,communicator);
}
void CartesianCommunicator::GlobalSumFVector(float *f,int N)
{
MPI_Allreduce(f,f,N,MPI_FLOAT,MPI_SUM,communicator);
}
void CartesianCommunicator::GlobalSumF(double &d)
{
MPI_Allreduce(&d,&d,1,MPI_DOUBLE,MPI_SUM,communicator);
}
void CartesianCommunicator::GlobalSumFVector(double *d,int N)
{
MPI_Allreduce(d,d,N,MPI_DOUBLE,MPI_SUM,communicator);
}
int CartesianCommunicator::ShiftedRank(int dim,int shift)
{
int rank;
MPI_Cart_shift(communicator,dim,shift,&_processor,&rank);
return rank;
}
int CartesianCommunicator::Rank(std::vector<int> coor)
{
int rank;
MPI_Cart_rank (communicator, &coor[0], &rank);
return rank;
}
// Basic Halo comms primitive
void CartesianCommunicator::SendToRecvFrom(void *xmit,
std::vector<int> &to_coordinate,
void *recv,
std::vector<int> &from_coordinate,
int bytes)
{
int dest = Rank(to_coordinate);
int from = Rank(from_coordinate);
MPI_Request x_req;
MPI_Request r_req;
MPI_Status OkeyDokey;
MPI_Isend(xmit, bytes, MPI_CHAR,dest,dest,communicator,&x_req);
MPI_Irecv(recv, bytes, MPI_CHAR,from,from,communicator,&r_req);
MPI_Wait(&x_req,&OkeyDokey);
MPI_Wait(&r_req,&OkeyDokey);
MPI_Barrier();
}
}
#if 0
// Could possibly do a direct block strided send?
int MPI_Type_vector(
int count,
int blocklength,
int stride,
MPI_Datatype old_type,
MPI_Datatype *newtype_p
);
#endif