From ad1808873e0dcd0c3a22aec2653a9a8a98cac21b Mon Sep 17 00:00:00 2001
From: Peter Munch <peterrmuench@gmail.com>
Date: Sat, 14 Oct 2023 19:26:37 +0200
Subject: [PATCH] Fix compute_prefix_sum() for serial run

---
 include/deal.II/lac/sparse_matrix_tools.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/deal.II/lac/sparse_matrix_tools.h b/include/deal.II/lac/sparse_matrix_tools.h
index 6a78644174..c4832c3107 100644
--- a/include/deal.II/lac/sparse_matrix_tools.h
+++ b/include/deal.II/lac/sparse_matrix_tools.h
@@ -151,6 +151,9 @@ namespace SparseMatrixTools
       (void)comm;
       return {0, value};
 #  else
+      if (comm == MPI_COMM_SELF)
+        return {0, value}; // serial triangulation
+
       T prefix = {};
 
       int ierr =
-- 
2.39.5