From: Peter Munch <peterrmuench@gmail.com>
Date: Mon, 22 Mar 2021 17:05:53 +0000 (+0100)
Subject: MF::check_vector_compatibility(): improve asser message
X-Git-Tag: v9.3.0-rc1~289^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F11951%2Fhead;p=dealii.git

MF::check_vector_compatibility(): improve asser message
---

diff --git a/include/deal.II/matrix_free/vector_access_internal.h b/include/deal.II/matrix_free/vector_access_internal.h
index 1874593d61..ce6c281e22 100644
--- a/include/deal.II/matrix_free/vector_access_internal.h
+++ b/include/deal.II/matrix_free/vector_access_internal.h
@@ -201,8 +201,11 @@ namespace internal
            ExcMessage(
              "The parallel layout of the given vector is not "
              "compatible with the parallel partitioning in MatrixFree. "
-             "Use MatrixFree::initialize_dof_vector to get a "
-             "compatible vector."));
+             "A potential reason is that you did not use "
+             "MatrixFree::initialize_dof_vector() to get a "
+             "compatible vector. If you did, the dof_handler_index "
+             "used there and the one passed to the constructor of "
+             "FEEvaluation do not match."));
   }