From: Wolfgang Bangerth Date: Wed, 9 Feb 2011 15:26:38 +0000 (+0000) Subject: Say a couple more things. X-Git-Tag: v8.0.0~4385 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=971d4e71f505dd0ec79aaf086f3d7fdaa866d456;p=dealii.git Say a couple more things. git-svn-id: https://svn.dealii.org/trunk@23313 0785d39b-7218-0410-832d-ea1e28bc413d --- diff --git a/deal.II/examples/step-2/doc/intro.dox b/deal.II/examples/step-2/doc/intro.dox index d12f73392e..46cacf2709 100644 --- a/deal.II/examples/step-2/doc/intro.dox +++ b/deal.II/examples/step-2/doc/intro.dox @@ -13,7 +13,14 @@ Defining degrees of freedom ("DoF"s in short) on a mesh is a rather simple task, since the library does all the work for you. Essentially, all you have to do is create a finite element object (from one of the many finite element classes deal.II already has, see for example the -@ref fe documentation) and give it to a DoFHandler object. +@ref fe documentation) and give it to a DoFHandler object through the +DoFHandler::distribute_dofs function. The DoFHandler is a class that +manages which degrees of freedom live where, i.e. it can answer +questions like "how many degrees of freedom are there globally" and +"on this cell, give me the global indices of the shape functions that +live here". This is the sort of information you need when determining +how big your system matrix should be, and when copying the +contributions of a single cell into the global matrix. The next step would then be to compute a matrix and right hand side corresponding to a particular differential equation using this finite