From: Lei Qiao <qiaol618@gmail.com>
Date: Mon, 13 Apr 2015 03:29:24 +0000 (-0500)
Subject: explain calling of compress() in step-40.
X-Git-Tag: v8.3.0-rc1~283^2~1
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a7009f28faa130defc51271ee318672a15d36665;p=dealii.git

explain calling of compress() in step-40.
---

diff --git a/examples/step-40/step-40.cc b/examples/step-40/step-40.cc
index e03278ce65..1d57447e9c 100644
--- a/examples/step-40/step-40.cc
+++ b/examples/step-40/step-40.cc
@@ -419,6 +419,11 @@ namespace Step40
                                                   system_rhs);
         }
 
+    // Notice that the assembling above is just a local operation. So, to
+    // fomulate the "global" linear system, a synchronization between all
+    // processors is needed. This could be done by invoke the function
+    // compress(). See @ref GlossCompress  "Compressing distributed objects"
+    // for more information on what is compress() designed to do.
     system_matrix.compress (VectorOperation::add);
     system_rhs.compress (VectorOperation::add);
   }