From 5ac75d0d12342d9a2ecc42180c10ff7a384f9454 Mon Sep 17 00:00:00 2001
From: amartin <alberto.martin@monash.edu>
Date: Wed, 1 Jun 2022 21:30:56 +1000
Subject: [PATCH] Added a new function get_local_array_read

---
 src/PETScArrays.jl       | 10 ++++++++++
 src/PartitionedArrays.jl |  2 +-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/PETScArrays.jl b/src/PETScArrays.jl
index 58232c8..1f455ba 100644
--- a/src/PETScArrays.jl
+++ b/src/PETScArrays.jl
@@ -166,6 +166,16 @@ function _get_local_vector(a::PETScVector)
   return v
 end
 
+# This function works with either ghosted or non-ghosted MPI vectors.
+# In the case of a ghosted vector it solely returns the locally owned
+# entries.
+function _get_local_vector_read(a::PETScVector)
+  r_pv = Ref{Ptr{PetscScalar}}()
+  @check_error_code PETSC.VecGetArrayRead(a.vec[], r_pv)
+  v = unsafe_wrap(Array, r_pv[], _local_size(a); own = false)
+  return v
+end
+
 function _restore_local_vector!(v::Array,a::PETScVector)
   @check_error_code PETSC.VecRestoreArray(a.vec[], Ref(pointer(v)))
   nothing
diff --git a/src/PartitionedArrays.jl b/src/PartitionedArrays.jl
index 2463dbf..ec5042e 100644
--- a/src/PartitionedArrays.jl
+++ b/src/PartitionedArrays.jl
@@ -119,7 +119,7 @@ function _copy!(pvec::PVector{T,<:MPIData},petscvec::Vec) where T
       # convert petscvec into a PVector to avoid extra memory allocation
       # and copies.
       @assert pvec.rows.ghost
-      lx=_get_local_vector(lg)
+      lx=_get_local_vector_read(lg)
       vvalues=view(values,indices.oid_to_lid)
       vvalues .= lx[1:num_oids(indices)]
       _restore_local_vector!(lx,lg)