From: bangerth <bangerth@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Thu, 11 Dec 2008 23:06:02 +0000 (+0000)
Subject: Document FEValuesViews changes.
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b01b913ca076c440ab27712335b57292e9711a58;p=dealii-svn.git

Document FEValuesViews changes.

git-svn-id: https://svn.dealii.org/trunk@17921 0785d39b-7218-0410-832d-ea1e28bc413d
---

diff --git a/deal.II/doc/news/changes.h b/deal.II/doc/news/changes.h
index 4c412e0214..ed988f0d1b 100644
--- a/deal.II/doc/news/changes.h
+++ b/deal.II/doc/news/changes.h
@@ -600,7 +600,24 @@ inconvenience this causes.
 <ol>
   <li>
   <p>
-  Upgraded: The FunctionParser classes now use version 2.83. 
+  Improved: The FEValuesViews objects that one gets when writing things
+  like <code>fe_values[velocities]</code> (see @ref vector_valued) have
+  become a lot smarter. They now compute a significant amount of data
+  at creation time, rather than on the fly. This means that creating such
+  objects becomes more expensive but using them is cheaper. To offset this
+  cost, FEValuesBase objects now create all possible FEValuesViews objects
+  at creation time, rather than whenever you do things like
+  <code>fe_values[velocities]</code>, and simply return a reference to a
+  pre-generated object. This turns an $O(N)$ effort into an $O(1)$
+  effort, where $N$ is the number of cells.
+  <br>
+  (Luca Heltai 2008/12/08)
+  </p>
+
+  <li>
+  <p>
+  Upgraded: The FunctionParser classes now use version 2.83 of the fparser
+  library. 
   <br>
   (Luca Heltai 2008/12/08)
   </p>