From cd7a17c06b79294eeea485dd50367e53b5664027 Mon Sep 17 00:00:00 2001
From: Martin Kronbichler <kronbichler@lnm.mw.tum.de>
Date: Mon, 3 Feb 2020 11:09:14 +0100
Subject: [PATCH] Avoid setting up an MPI data type for serial comm

---
 source/base/mpi.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/source/base/mpi.cc b/source/base/mpi.cc
index 400a787440..334453313e 100644
--- a/source/base/mpi.cc
+++ b/source/base/mpi.cc
@@ -531,7 +531,8 @@ namespace Utilities
     {
       // If MPI was not started, we have a serial computation and cannot run
       // the other MPI commands
-      if (job_supports_mpi() == false)
+      if (job_supports_mpi() == false ||
+          Utilities::MPI::n_mpi_processes(mpi_communicator) <= 1)
         {
           MinMaxAvg result;
           result.sum       = my_value;
-- 
2.39.5