NAME

       quadrangle - reference element (rheolef-7.2)

DESCRIPTION

       The quadrangle reference_element(6) is K = [-1,1]^2.

           x1

           3---------2
           |         |
           |         |
           |         |
           |         |
           0---------1--->  x0

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

       Curved high order Pk quadrangles (k >= 1), in 2D or 3D geometries, are supported. These
       quadrangles have additional edge-nodes and face-nodes. These nodes are numbered as: first
       vertex, then edge-node, following the edge numbering order and orientation, and finally
       the face internal nodes, following the quadrangle lattice.

           3-----6-----2   3---9---8---2
           |           |   |           |
           |           |  10  14  15   7
           7     8     5   |           |
           |           |  11  12  13   6
           |           |   |           |
           0-----4-----1   0---4---5---1
                 P2              P3

IMPLEMENTATION

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

       const size_t dimension = 2;
       const Float  measure = 4;
       const size_t n_vertex = 4;
       const point vertex [n_vertex] = {
               point(-1,-1),
               point( 1,-1),
               point( 1, 1),
               point(-1, 1) };
       const size_t  n_edge = 4;
       const size_t edge [n_edge][2] = {
               { 0, 1 },
               { 1, 2 },
               { 2, 3 },
               { 3, 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.