From: Wolfgang Bangerth Date: Fri, 20 Feb 2015 22:29:50 +0000 (-0600) Subject: Update a few comments. X-Git-Tag: v8.3.0-rc1~433^2~4 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7efe6eacdf81c23948e3a014e74be665f68b5f16;p=dealii.git Update a few comments. --- diff --git a/include/deal.II/fe/fe_system.h b/include/deal.II/fe/fe_system.h index 4a6be4b77e..abcbd707aa 100644 --- a/include/deal.II/fe/fe_system.h +++ b/include/deal.II/fe/fe_system.h @@ -1,6 +1,6 @@ // --------------------------------------------------------------------- // -// Copyright (C) 1999 - 2014 by the deal.II authors +// Copyright (C) 1999 - 2015 by the deal.II authors // // This file is part of the deal.II library. // @@ -156,17 +156,32 @@ class FESystem : public FiniteElement public: /** - * Constructor. Take a finite element type and the number of elements you + * Constructor. Take a finite element and the number of elements you * want to group together using this class. * - * In fact, the object @p fe is not used, apart from getting the number of - * dofs per vertex, line, etc for that finite element class. The objects - * creates its own copy of the finite element object at construction time - * (but after the initialization of the base class @p FiniteElement, which - * is why we need a valid finite element object passed to the constructor). - * - * Obviously, the template finite element class needs to be of the same - * dimension as is this object. + * The object @p fe is not actually used for anything other than creating + * a copy that will then be owned by the current object. In other words, + * it is completely fine to call this constructor with a temporary object + * for the finite element, as in this code snippet: + * @code + * FESystem fe (FE_Q(2), 2); + * @endcode + * Here, FE_Q@(2) constructs an unnamed, temporary + * object that is passed to the FESystem constructor to create a + * finite element that consists of two components, both of which are + * quadratic FE_Q elements. The temporary is destroyed again at the + * end of the code that corresponds to this line, but this does not + * matter because FESystem creates its own copy of the FE_Q object. + * + * This constructor (or its variants below) is used in essentially all + * tutorial programs that deal with vector valued problems. See step-8, + * step-20, step-22 and others for use cases. Also see the module on + * @ref vector_valued "Handling vector valued problems". + * + * @param[in] fe The finite element that will be used to represent + * the components of this composed element. + * @param[in] n_elements An integer denoting how many copies of + * @fe this element should consist of. */ FESystem (const FiniteElement &fe, const unsigned int n_elements); @@ -174,7 +189,8 @@ public: /** * Constructor for mixed discretizations with two base elements. * - * See the other constructor. + * See the other constructor above for an explanation of the + * general idea of composing elements. */ FESystem (const FiniteElement &fe1, const unsigned int n1, const FiniteElement &fe2, const unsigned int n2); @@ -182,7 +198,8 @@ public: /** * Constructor for mixed discretizations with three base elements. * - * See the other constructor. + * See the other constructor above for an explanation of the + * general idea of composing elements. */ FESystem (const FiniteElement &fe1, const unsigned int n1, const FiniteElement &fe2, const unsigned int n2, @@ -191,7 +208,8 @@ public: /** * Constructor for mixed discretizations with four base elements. * - * See the other constructor. + * See the first of the other constructors above for an explanation of the + * general idea of composing elements. */ FESystem (const FiniteElement &fe1, const unsigned int n1, const FiniteElement &fe2, const unsigned int n2, @@ -201,7 +219,8 @@ public: /** * Constructor for mixed discretizations with five base elements. * - * See the other constructor. + * See the first of the other constructors above for an explanation of the + * general idea of composing elements. */ FESystem (const FiniteElement &fe1, const unsigned int n1, const FiniteElement &fe2, const unsigned int n2,