From f2c75c9766036cfcfe0664225bbc829c913fd9bd Mon Sep 17 00:00:00 2001 From: bangerth Date: Thu, 16 Sep 2010 21:12:19 +0000 Subject: [PATCH] Add provisional version, to be finished at home later today. git-svn-id: https://svn.dealii.org/trunk@22003 0785d39b-7218-0410-832d-ea1e28bc413d --- deal.II/doc/doxygen/headers/constraints.h | 38 +++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 deal.II/doc/doxygen/headers/constraints.h diff --git a/deal.II/doc/doxygen/headers/constraints.h b/deal.II/doc/doxygen/headers/constraints.h new file mode 100644 index 0000000000..432749488a --- /dev/null +++ b/deal.II/doc/doxygen/headers/constraints.h @@ -0,0 +1,38 @@ +//------------------------------------------------------------------------- +// $Id$ +// Version: $Name$ +// +// Copyright (C) 2010 by the deal.II authors +// +// This file is subject to QPL and may not be distributed +// without copyright and license information. Please refer +// to the file deal.II/doc/license.html for the text and +// further information on this license. +// +//------------------------------------------------------------------------- + +/** + * @defgroup constraints Constraints on degrees of freedom + * @ingroup dofs + * + * This module deals with constraints on degrees of + * freedom. Constraints typically come from several sources, for + * example: + * - If you have Dirichlet-type boundary conditions, one usually enforces + * them by requiring that that degrees of freedom on the boundary have + * particular values, for example $x_12=42$ if the boundary condition + * requires that the finite element solution at the location of degree + * of freedom 12 has the value 42. + * + * This class implements dealing with linear (possibly inhomogeneous) + * constraints on degrees of freedom. In particular, it handles constraints of + * the form $x_{i_1} = \sum_{j=2}^M a_{i_j} x_{i_j} + b_i$. In the context of + * adaptive finite elements, such constraints appear most frequently as + * "hanging nodes" and for implementing Dirichlet boundary conditions in + * strong form. The class is meant to deal with a limited number of + * constraints relative to the total number of degrees of freedom, for example + * a few per cent up to maybe 30 per cent; and with a linear combination of + * $M$ other degrees of freedom where $M$ is also relatively small (no larger + * than at most around the average number of entries per row of a linear + * system). It is not meant to describe full rank linear systems. + */ -- 2.39.5