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periodicX communication fixes #3109

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Merged
bendudson merged 1 commit into from
May 12, 2025
+51 −18
Merged

periodicX communication fixes #3109

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5 changes: 3 additions & 2 deletions src/mesh/fv_ops.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -442,8 +442,9 @@ void communicateFluxes(Field3D& f) {
comm_handle xin, xout;
// Cache results to silence spurious compiler warning about xin,
// xout possibly being uninitialised when used
bool not_first = !mesh->firstX();
bool not_last = !mesh->lastX();
const bool not_first = mesh->periodicX || !mesh->firstX();
const bool not_last = mesh->periodicX || !mesh->lastX();

if (not_first) {
xin = mesh->irecvXIn(f(0, 0), size, 0);
}
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64 changes: 48 additions & 16 deletions src/mesh/impls/bout/boutmesh.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -1534,42 +1534,66 @@ bool BoutMesh::firstX() const { return PE_XIND == 0; }
bool BoutMesh::lastX() const { return PE_XIND == NXPE - 1; }

int BoutMesh::sendXOut(BoutReal* buffer, int size, int tag) {
Timer timer("comms");

int proc {-1};
if (PE_XIND == NXPE - 1) {
return 1;
if (periodicX) {
// Wrap around to first processor in X
proc = PROC_NUM(0, PE_YIND);
} else {
return 1;
}
} else {
proc = PROC_NUM(PE_XIND + 1, PE_YIND);
}

Timer timer("comms");

mpi->MPI_Send(buffer, size, PVEC_REAL_MPI_TYPE, PROC_NUM(PE_XIND + 1, PE_YIND), tag,
mpi->MPI_Send(buffer, size, PVEC_REAL_MPI_TYPE, proc, tag,
BoutComm::get());

return 0;
}

int BoutMesh::sendXIn(BoutReal* buffer, int size, int tag) {
Timer timer("comms");

int proc {-1};
if (PE_XIND == 0) {
return 1;
if (periodicX) {
// Wrap around to last processor in X
proc = PROC_NUM(NXPE - 1, PE_YIND);
} else {
return 1;
}
} else {
proc = PROC_NUM(PE_XIND - 1, PE_YIND);
}

Timer timer("comms");

mpi->MPI_Send(buffer, size, PVEC_REAL_MPI_TYPE, PROC_NUM(PE_XIND - 1, PE_YIND), tag,
mpi->MPI_Send(buffer, size, PVEC_REAL_MPI_TYPE, proc, tag,
BoutComm::get());

return 0;
}

comm_handle BoutMesh::irecvXOut(BoutReal* buffer, int size, int tag) {
Timer timer("comms");

int proc {-1};
if (PE_XIND == NXPE - 1) {
return nullptr;
if (periodicX) {
// Wrap around to first processor in X
proc = PROC_NUM(0, PE_YIND);
} else {
return nullptr;
}
} else {
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warning: do not implicitly decay an array into a pointer; consider using gsl::array_view or an explicit cast instead [cppcoreguidelines-pro-bounds-array-to-pointer-decay]

                 BoutComm::get(), ch->request);
                                  ^

proc = PROC_NUM(PE_XIND + 1, PE_YIND);
}

Timer timer("comms");

// Get a communications handle. Not fussy about size of arrays
CommHandle* ch = get_handle(0, 0);

mpi->MPI_Irecv(buffer, size, PVEC_REAL_MPI_TYPE, PROC_NUM(PE_XIND + 1, PE_YIND), tag,
mpi->MPI_Irecv(buffer, size, PVEC_REAL_MPI_TYPE, proc, tag,
BoutComm::get(), ch->request);

ch->in_progress = true;
Expand All @@ -1578,16 +1602,24 @@ comm_handle BoutMesh::irecvXOut(BoutReal* buffer, int size, int tag) {
}

comm_handle BoutMesh::irecvXIn(BoutReal* buffer, int size, int tag) {
Timer timer("comms");

int proc {-1};
if (PE_XIND == 0) {
return nullptr;
if (periodicX) {
// Wrap around to last processor in X
proc = PROC_NUM(NXPE - 1, PE_YIND);
} else {
return nullptr;
}
} else {
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proc = PROC_NUM(PE_XIND - 1, PE_YIND);
}

Timer timer("comms");

// Get a communications handle. Not fussy about size of arrays
CommHandle* ch = get_handle(0, 0);

mpi->MPI_Irecv(buffer, size, PVEC_REAL_MPI_TYPE, PROC_NUM(PE_XIND - 1, PE_YIND), tag,
mpi->MPI_Irecv(buffer, size, PVEC_REAL_MPI_TYPE, proc, tag,
BoutComm::get(), ch->request);

ch->in_progress = true;
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