From 7c294b14328c309f29b3630bfa02aaf7b3b0df25 Mon Sep 17 00:00:00 2001
From: heister <heister@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Fri, 8 Mar 2013 23:14:41 +0000
Subject: [PATCH] add comment about numdiff in docu

git-svn-id: https://svn.dealii.org/trunk@28828 0785d39b-7218-0410-832d-ea1e28bc413d
---
 deal.II/doc/development/testsuite.html | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/deal.II/doc/development/testsuite.html b/deal.II/doc/development/testsuite.html
index 8676f4f330..0b0df74bb8 100644
--- a/deal.II/doc/development/testsuite.html
+++ b/deal.II/doc/development/testsuite.html
@@ -161,6 +161,16 @@
     CMake to install deal.II into previously.
     </p>
 
+    <p>
+    Not all tests will succeed on your machine, because you might not have
+    configured with all the required packages (for example PETSc or Trilinos)
+    or, because your machine has slightly different floating point outputs.
+    To improve the number of tests that work correctly, install the tool
+    numdiff and export the environment variable
+    <code>export DEALII_DIFF="numdiff -a 1e-6 -q"</code> 
+    before running the testsuite.
+    </p>
+
     <p>
     Once you have done this, you may simply type
     <code>make</code>. This runs all the tests there are, but stops at
-- 
2.39.5