From: Wolfgang Bangerth Date: Mon, 28 Sep 2020 22:58:43 +0000 (-0600) Subject: Update documentation of class Triangulation. X-Git-Tag: v9.3.0-rc1~1058^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bbe03873777c46da8e8017b94029a5366bf393ee;p=dealii.git Update documentation of class Triangulation. --- diff --git a/include/deal.II/grid/tria.h b/include/deal.II/grid/tria.h index 24920d3032..6acd2da16f 100644 --- a/include/deal.II/grid/tria.h +++ b/include/deal.II/grid/tria.h @@ -320,9 +320,12 @@ namespace internal /** - * Triangulations denote a hierarchy of levels of elements which together form - * a @p dim -dimensional manifold in @p spacedim spatial dimensions (if - * spacedim is not specified it takes the default value @p spacedim=dim). + * A triangulation is a collection of cells that, jointly, cover the domain + * on which one typically wants to solve a partial differential equation. + * This domain, and the mesh that covers it, represents a @p dim -dimensional manifold + * and lives in @p spacedim spatial dimensions, where @p dim and @p spacedim + * are the template arguments of this class. (If @p spacedim is not specified, + * it takes the default value `spacedim=dim`.) * * Thus, for example, an object of type @p Triangulation<1,1> (or simply @p * Triangulation<1> since @p spacedim==dim by default) is used to represent @@ -332,6 +335,16 @@ namespace internal * associated with curves in 2D or surfaces in 3D) are the ones one wants to * use in the boundary element method. * + * The name of the class is mostly hierarchical and is not meant to imply that + * a Triangulation can only consist of triangles. Instead, triangulations + * consist of line segments in 1d (i.e., if `dim==1`), and of three-dimensional + * cells (if `dim==3`). Moreover, historically, deal.II only supported + * quadrilaterals (cells with four vertices: deformed rectangles) in 2d + * and hexahedra (cells with six sides and eight vertices that are deformed + * boxes), neither of which are triangles. In other words, the term + * "triangulation" in the deal.II language is synonymous with "mesh" and is + * to be understood separate from its linguistic origin. + * * This class is written to be as independent of the dimension as possible * (thus the complex construction of the * dealii::internal::TriangulationImplementation::TriaLevel classes) to allow