From 1990eea2a4263011a5f381bed88d4596d46ffc04 Mon Sep 17 00:00:00 2001 From: bangerth Date: Mon, 24 Oct 2011 19:58:22 +0000 Subject: [PATCH] Add a paragraph. git-svn-id: https://svn.dealii.org/trunk@24671 0785d39b-7218-0410-832d-ea1e28bc413d --- deal.II/doc/doxygen/headers/dofs.h | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/deal.II/doc/doxygen/headers/dofs.h b/deal.II/doc/doxygen/headers/dofs.h index 8b9f7374ad..9a324be081 100644 --- a/deal.II/doc/doxygen/headers/dofs.h +++ b/deal.II/doc/doxygen/headers/dofs.h @@ -2,7 +2,7 @@ // $Id$ // Version: $Name$ // -// Copyright (C) 2003, 2005, 2006, 2010 by the deal.II authors +// Copyright (C) 2003, 2005, 2006, 2010, 2011 by the deal.II authors // // This file is subject to QPL and may not be distributed // without copyright and license information. Please refer @@ -24,13 +24,28 @@ * parallel::distributed::DoFHandler and MGDoFHandler that do similar * things for more special cases. * + * DoFHandler objects are used together with objects of type FiniteElement + * (or hp::FECollection in the case of hp::DoFHandler) to enumerate all the + * degrees of freedom that exist in a triangulation for this particular + * finite element. As such, the combination of mesh, finite element, and + * DoF handler object can be thought of as providing a basis of + * the finite element space: the mesh provides the locations at which basis + * functions are defined; the finite element describes what kinds of basis + * functions exist; and the DoF handler object provides an enumeration of + * the basis, i.e., it is provides a concrete structure of the space so that + * we can describe functions in this finite dimensional space by vectors + * of coefficients. + * * DoFHandlers extend Triangulation objects (and the other classes in the @ref * grid module) in that they, too, offer iterators that run over all cells, * faces, or other geometric objects that make up a triangulation. These * iterators are derived from the triangulation iterators and therefore offer * the same functionality, but they also offer additional functions. For * example, they allow to query the indices of the degrees of freedom - * associated with the present cell. + * associated with the present cell. Note that DoFHandler classes are not + * derived from Triangulation, though they use Triangulation objects; + * the reason is that there can be more than one DoFHandler object that works + * on the same Triangulation object. * * In addition to the DoF handler classes, this module holds a number of * auxiliary classes not commonly used in application programs, as well as -- 2.39.5