debian man page for triangle

triangle(7rheolef)						    rheolef-6.1 						triangle(7rheolef)

NAME
       triangle - Triangle reference element

DESCRIPTION
       The triangle reference element is

	       K = { 0 < x < 1 and 0 < y < 1-x }

NUMBERING
	     y

	     2
	     | +
	     |	 +
	     |	   +
	     |	     +
	     0---------1   x

       Curved high order Pk triangles (k >= 1), in 2d or 3d geometries, are supported.	These triangles 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 tri-
       angle lattice.  See below for edge numbering and orientation.

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

rheolef-6.1							    rheolef-6.1 						triangle(7rheolef)