From: Stefano Zampini <stefano.zampini@gmail.com>
Date: Sun, 27 Nov 2022 06:15:54 +0000 (+0300)
Subject: PETScWrappers::MPI::BlockVector Add missing conversion operator for const
X-Git-Tag: v9.5.0-rc1~621^2~5
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cb12978dd8104cff2cd82aef333dc05221ebfd46;p=dealii.git

PETScWrappers::MPI::BlockVector Add missing conversion operator for const
---

diff --git a/include/deal.II/lac/petsc_block_vector.h b/include/deal.II/lac/petsc_block_vector.h
index 71d9589053..670f2061d4 100644
--- a/include/deal.II/lac/petsc_block_vector.h
+++ b/include/deal.II/lac/petsc_block_vector.h
@@ -272,6 +272,15 @@ namespace PETScWrappers
       const MPI_Comm &
       get_mpi_communicator() const;
 
+      /**
+       * Conversion operator to gain access to the underlying PETSc type. If you
+       * do this, you cut this class off some information it may need, so this
+       * conversion operator should only be used if you know what you do. In
+       * particular, it should only be used for read-only operations into the
+       * vector.
+       */
+      operator const Vec &() const;
+
       /**
        * Return a reference to the underlying PETSc type. It can be used to
        * modify the underlying data, so use it only when you know what you
diff --git a/source/lac/petsc_parallel_block_vector.cc b/source/lac/petsc_parallel_block_vector.cc
index c00e9dbdcd..88360c6d81 100644
--- a/source/lac/petsc_parallel_block_vector.cc
+++ b/source/lac/petsc_parallel_block_vector.cc
@@ -93,6 +93,11 @@ namespace PETScWrappers
       return petsc_nest_vector;
     }
 
+    BlockVector::operator const Vec &() const
+    {
+      return petsc_nest_vector;
+    }
+
     void
     BlockVector::collect_sizes()
     {