From 6cea389e1f920e0f2d0b7c1cca1621628ff6bfb4 Mon Sep 17 00:00:00 2001
From: Dmitri Naumov <github@naumov.de>
Date: Fri, 1 Nov 2024 15:46:50 +0100
Subject: [PATCH] [MaL/PETSc] allgatherv replaces gatherLocalVectors
---
MathLib/LinAlg/PETSc/PETScVector.cpp | 18 ++----------------
MathLib/LinAlg/PETSc/PETScVector.h | 8 --------
2 files changed, 2 insertions(+), 24 deletions(-)
diff --git a/MathLib/LinAlg/PETSc/PETScVector.cpp b/MathLib/LinAlg/PETSc/PETScVector.cpp
index 13ca4b1ee4c..a6201f116d8 100644
--- a/MathLib/LinAlg/PETSc/PETScVector.cpp
+++ b/MathLib/LinAlg/PETSc/PETScVector.cpp
@@ -115,21 +115,6 @@ void PETScVector::finalizeAssembly()
VecAssemblyEnd(v_);
}
-void PETScVector::gatherLocalVectors(PetscScalar local_array[],
- PetscScalar global_array[]) const
-{
- BaseLib::MPI::Mpi mpi{PETSC_COMM_WORLD};
-
- // number of elements to be sent for each rank
- std::vector<PetscInt> const i_cnt = BaseLib::MPI::allgather(size_loc_, mpi);
-
- // offset in the receive vector of the data from each rank
- std::vector<PetscInt> const i_disp = BaseLib::sizesToOffsets(i_cnt);
-
- MPI_Allgatherv(local_array, size_loc_, MPI_DOUBLE, global_array, &i_cnt[0],
- &i_disp[0], MPI_DOUBLE, PETSC_COMM_WORLD);
-}
-
void PETScVector::getGlobalVector(std::vector<PetscScalar>& u) const
{
#ifdef TEST_MEM_PETSC
@@ -149,7 +134,8 @@ void PETScVector::getGlobalVector(std::vector<PetscScalar>& u) const
PetscScalar* xp = nullptr;
VecGetArray(v_, &xp);
- gatherLocalVectors(xp, u.data());
+ BaseLib::MPI::Mpi mpi{PETSC_COMM_WORLD};
+ BaseLib::MPI::allgatherv(std::span(xp, size_loc_), u, mpi);
// This following line may be needed late on
// for a communication load balance:
diff --git a/MathLib/LinAlg/PETSc/PETScVector.h b/MathLib/LinAlg/PETSc/PETScVector.h
index ed2734878fb..20983dacf2d 100644
--- a/MathLib/LinAlg/PETSc/PETScVector.h
+++ b/MathLib/LinAlg/PETSc/PETScVector.h
@@ -267,14 +267,6 @@ private:
/// Map global indices of ghost entries to local indices
mutable std::map<PetscInt, PetscInt> global_ids2local_ids_ghost_;
- /*!
- \brief Collect local vectors
- \param local_array Local array
- \param global_array Global array
- */
- void gatherLocalVectors(PetscScalar local_array[],
- PetscScalar global_array[]) const;
-
/*!
Get local vector, i.e. entries in the same rank
*/
--
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