From f13c29424a92694d19b8fc24af9d41c19f3b3c08 Mon Sep 17 00:00:00 2001 From: Wolfgang Bangerth Date: Wed, 13 Apr 2011 14:22:30 +0000 Subject: [PATCH] Add link. Fix formatting. git-svn-id: https://svn.dealii.org/trunk@23587 0785d39b-7218-0410-832d-ea1e28bc413d --- deal.II/include/deal.II/fe/fe_nothing.h | 33 ++++++++++++++----------- 1 file changed, 18 insertions(+), 15 deletions(-) diff --git a/deal.II/include/deal.II/fe/fe_nothing.h b/deal.II/include/deal.II/fe/fe_nothing.h index 41b06f1ec7..88c308f615 100644 --- a/deal.II/include/deal.II/fe/fe_nothing.h +++ b/deal.II/include/deal.II/fe/fe_nothing.h @@ -1,7 +1,7 @@ //--------------------------------------------------------------------------- // $Id$ // -// Copyright (C) 2009, 2010 by the deal.II authors +// Copyright (C) 2009, 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 @@ -22,49 +22,52 @@ DEAL_II_NAMESPACE_OPEN /*@{*/ /** - * Definition of a finite element with zero degrees of freedom. This - * class is useful (in the context of an hp method) to represent empty - * cells in the triangulation on which no degrees of freedom should - * be allocated. Thus a triangulation may be divided into two regions: - * an active region where normal elements are used, and an inactive - * region where FE_Nothing elements are used. The hp::DoFHandler will - * therefore assign no degrees of freedom to the FE_Nothing cells, and - * this subregion is therefore implicitly deleted from the computation. + * Definition of a finite element with zero degrees of freedom. This class is + * useful (in the context of an hp method) to represent empty cells in the + * triangulation on which no degrees of freedom should be allocated, or to + * describe a field that is extended by zero to a part of the domain where we + * don't need it. Thus a triangulation may be divided into two regions: an + * active region where normal elements are used, and an inactive region where + * FE_Nothing elements are used. The hp::DoFHandler will therefore assign no + * degrees of freedom to the FE_Nothing cells, and this subregion is therefore + * implicitly deleted from the computation. step-46 shows a use case for this + * element. * * Note that some care must be taken that the resulting mesh topology * continues to make sense when FE_Nothing elements are introduced. * This is particularly true when dealing with hanging node constraints, * because the library makes some basic assumptions about the nature * of those constraints. The following geometries are acceptable: - * + * @code * +---------+----+----+ * | | 0 | | * | 1 +----+----+ * | | 0 | | * +---------+----+----+ - * + * @endcode + * @code * +---------+----+----+ * | | 1 | | * | 0 +----+----+ * | | 1 | | * +---------+----+----+ - * + * @encode * Here, 0 denotes an FE_Nothing cell, and 1 denotes some other * element type. The library has no difficulty computing the necessary * hanging node constraints in these cases (i.e. no constraint). * However, the following geometry is NOT acceptable (at least * in the current implementation): - * + * @code * +---------+----+----+ * | | 0 | | * | 1 +----+----+ * | | 1 | | * +---------+----+----+ - * + * @endcode * The distinction lies in the mixed nature of the child faces, * a case we have not implemented as of yet. * - * @author Joshua White + * @author Joshua White, Wolfgang Bangerth */ template class FE_Nothing : public FiniteElement -- 2.39.5