From fab890207aaa7300f229973b9f7acfd515b338d4 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Fri, 19 Jan 2018 18:04:32 -0700
Subject: [PATCH] Address what 'sequential' means in the context of
 communicators.

---
 include/deal.II/base/mpi.h       | 5 ++++-
 include/deal.II/base/utilities.h | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/deal.II/base/mpi.h b/include/deal.II/base/mpi.h
index 2790c9e8b0..2902516e8f 100644
--- a/include/deal.II/base/mpi.h
+++ b/include/deal.II/base/mpi.h
@@ -75,7 +75,10 @@ namespace Utilities
     /**
      * Return the number of MPI processes there exist in the given
      * @ref GlossMPICommunicator "communicator"
-     * object. If this is a sequential job, it returns 1.
+     * object. If this is a sequential job (i.e., the program
+     * is not using MPI at all, or is using MPI but has been started with
+     * only one MPI process), then the communicator necessarily involves
+     * only one process and the function returns 1.
      */
     unsigned int n_mpi_processes (const MPI_Comm &mpi_communicator);
 
diff --git a/include/deal.II/base/utilities.h b/include/deal.II/base/utilities.h
index e1b091e798..06abd5cd43 100644
--- a/include/deal.II/base/utilities.h
+++ b/include/deal.II/base/utilities.h
@@ -596,7 +596,10 @@ namespace Utilities
 
     /**
      * Return the number of MPI processes there exist in the given
-     * communicator object. If this is a sequential job, it returns 1.
+     * communicator object. If this is a sequential job (i.e., the program
+     * is not using MPI at all, or is using MPI but has been started with
+     * only one MPI process), then the communicator necessarily involves
+     * only one process and the function returns 1.
      */
     unsigned int get_n_mpi_processes (const Epetra_Comm &mpi_communicator);
 
-- 
2.39.5