Read<T> Comm::alltoallv(Read<T> sendbuf_dev, Read<LO> sendcounts_dev,
Read<LO> sdispls_dev, Read<LO> recvcounts_dev, Read<LO> rdispls_dev) const {
#ifdef OMEGA_H_USE_MPI
HostRead<T> sendbuf(sendbuf_dev);
HostRead<LO> sendcounts(sendcounts_dev);
HostRead<LO> recvcounts(recvcounts_dev);
HostRead<LO> sdispls(sdispls_dev);
HostRead<LO> rdispls(rdispls_dev);
CHECK(rdispls.size() == recvcounts.size() + 1);
int nrecvd = rdispls.last();
HostWrite<T> recvbuf(nrecvd);
CHECK(sendcounts.size() == host_dsts_.size());
CHECK(recvcounts.size() == host_srcs_.size());
CHECK(sdispls.size() == sendcounts.size() + 1);
CHECK(sendbuf.size() == sdispls.last());
CALL(Neighbor_alltoallv(host_srcs_, host_dsts_, sendbuf.data(),
sendcounts.data(), sdispls.data(), MpiTraits<T>::datatype(),
recvbuf.data(), recvcounts.data(), rdispls.data(),
MpiTraits<T>::datatype(), impl_));
return recvbuf.write();
#else
(void)sendcounts_dev;
(void)recvcounts_dev;
(void)sdispls_dev;
(void)rdispls_dev;
return sendbuf_dev;
#endif
}
void dummy_operations::run_collective_dummy_operations() {
int rank, size;
MPI_Comm_rank( MPI_COMM_WORLD, &rank);
MPI_Comm_size( MPI_COMM_WORLD, &size);
// Run Broadcast
{
int x;
MPI_Comm_rank( MPI_COMM_WORLD, &x);
MPI_Bcast(&x, 1, MPI_INT, 0, MPI_COMM_WORLD);
}
// Run Allgather.
{
int x, size;
MPI_Comm_rank( MPI_COMM_WORLD, &x);
MPI_Comm_size( MPI_COMM_WORLD, &size);
std::vector<int> rcv(size);
MPI_Allgather(&x, 1, MPI_INT, &rcv[0], 1, MPI_INT, MPI_COMM_WORLD);
}
// Run Allreduce.
{
int x;
MPI_Comm_rank( MPI_COMM_WORLD, &x);
int y = 0;
MPI_Allreduce(&x, &y, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
}
// Dummy Prefix Sum
{
int x = 1;
int y = 0;
MPI_Scan(&x, &y, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
}
// Run Alltoallv.
{
std::vector<int> snd(size);
std::vector<int> rcv(size);
std::vector<int> scounts(size, 1);
std::vector<int> rcounts(size, 1);
std::vector<int> sdispls(size);
std::vector<int> rdispls(size);
for (int i = 0, iend = sdispls.size(); i < iend; ++i) {
sdispls[i] = rdispls[i] = i;
}
MPI_Alltoallv(&snd[0], &scounts[0], &sdispls[0], MPI_INT,
&rcv[0], &rcounts[0], &rdispls[0], MPI_INT, MPI_COMM_WORLD);
}
}
