NAME

       triangle - reference element (rheolef-7.2)

DESCRIPTION

       The triangle reference_element(6) is K = [0,1].

           K = { 0 < x0 < 1 and 0 < x1 < 1-x0 }

           x1
           2
           | +
           |   +
           |     +
           |       +
           0---------1  x0

        This two-dimensional reference_element(6) is then transformed, after the Piola
       geometrical application, as a triangle in a 2D or 3D physical space, as a geo_element(6).

       Curved high order transformed geo_element(6) Pk triangle (k >= 1) are supported for 2D or
       3D geometries. In these cases, the nodes of an high-order triangle are numbered as:

       Note that high-order triangles have additional edge-nodes and face-nodes. These nodes are
       numbered as: first vertices, then edge-nodes, following the edge numbering order and
       orientation, and finally the face internal nodes, following the triangle lattice.

         2               2               2
         | +             | +             | +
         |   +           7   6           9   8
         5     4         |     +        10 14  7
         |       +       8   9   5      11 12 13 6
         |         +     |         +     |         +
         0-----3-----1   0---3---4---1   0--3--4--5--1
               P2              P3              P4

IMPLEMENTATION

       This documentation has been generated from file fem/geo_element/triangle.icc

       const size_t dimension = 2;
       const Float  measure = 0.5;
       const size_t n_vertex = 3;
       const point vertex [n_vertex] = {
               point(0, 0),
               point(1, 0),
               point(0, 1) };
       const size_t  n_edge = 3;
       const size_t edge [n_edge][2] = {
               { 0, 1 },
               { 1, 2 },
               { 2, 0 } };

AUTHOR

       Pierre  Saramito  <Pierre.Saramito@imag.fr>

COPYRIGHT

       Copyright   (C)  2000-2018  Pierre  Saramito  <Pierre.Saramito@imag.fr> GPLv3+: GNU GPL
       version 3 or later  <http://gnu.org/licenses/gpl.html>.  This  is  free  software:  you
       are free to change and redistribute it.  There is NO WARRANTY, to the extent permitted by
       law.