From: Wolfgang Bangerth Date: Sun, 13 Dec 2015 17:35:22 +0000 (-0600) Subject: Update the introduction to the concepts page. X-Git-Tag: v8.4.0-rc2~156^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F1981%2Fhead;p=dealii.git Update the introduction to the concepts page. --- diff --git a/doc/doxygen/headers/concepts.h b/doc/doxygen/headers/concepts.h index 1cc7cb09bc..bd85cd4651 100644 --- a/doc/doxygen/headers/concepts.h +++ b/doc/doxygen/headers/concepts.h @@ -24,14 +24,31 @@ * their intent. The convention in deal.II for listing constraints on a type * is to provide the name of the concept as a typename in a * template: for example, the type of a Vector depends on the type of the - * underlying field, but Vector is not a field element, so it is defined as a + * underlying field, and so it is defined as a * template: * @code * template * class Vector; * @endcode - * Where @ref ConceptNumber "Number" is understood to be an appropriate field - * element type. + * The point here is that you are creating a vector that can store + * elements of type @p Number. But there are some underlying + * assumptions on this. For example, the deal.II Vector class is not + * intended to be used just as a collection (unlike + * std::vector) but defines vector space operations such + * as addition of vectors, or the norm of vectors. Consequently, the + * data type users can specify for @p Number must satisfy certain + * conditions (i.e., it must conform to or "model" a "concept"): + * Specifically, the type must denote objects that represent the + * elements of what mathematically call a "field" (which you can think + * of as, well, "numbers": things we can add, multiply, divide, take + * the absolute value of, etc). The point of a concept is then to + * describe what conditions a type must satisfy to be a valid + * template argument in a given context. + * + * This page describes these conditions for a number of concepts used + * throughout deal.II. Specifically, in the example above, the + * @ref ConceptNumber "Number concept" discussed below describes the + * types that could be used as argument for the Vector class. * *
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