debian man page for tetrahedron

tetrahedron(7rheolef)						    rheolef-6.1 					     tetrahedron(7rheolef)

NAME
       tetrahedron - Tetraedron reference element

DESCRIPTION
       The tetrahedron reference element is

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

			      z
			    .
			  ,/
			 /
		       3
		     ,/|`
		   ,/  |  `
		 ,/    '.   `
	       ,/	|     `
	     ,/ 	|	`
	    0-----------'.--------2 --> y
	     `.	 |	,/
		`.	 |    ,/
		   `.	 '. ,/
		      `. |/
			 `1
			    `.
			      ` x

       Curved  high  order  Pk	tetrahedra  (k	>= 1) in 3d geometries are supported.  These tetrahedra have additional edge-nodes, face-nodes and
       internal volume-nodes.

THESE NODES ARE NUMBERED AS
	first vertex, then edge-node, following the edge numbering order and orientation, then face-nodes following the face numbering	order  and
       orientation, and finally the face internal nodes, following the tetrahedron lattice.  See below for edges and faces numbering and orioenta-
       tion.

		       3
		     ,/|`
		   ,/  |  `
		 ,7    '.   `9
	       ,/	|     `
	     ,/ 	8	`
	    0--------6--'.--------2
	     `.	 |	,/
		`.	 |    ,5
		   `4.	 '. ,/
		      `. |/
			 `1
		      P2

NUMBERING
       The orientation is such that triedra (01, 02, 03) is direct, and all faces, see from exterior, are in the direct sens.  References:  P.	L.
       Georges,  "Generation automatique de maillages", page 24-, coll RMA, 16, Masson, 1994.  Notice that the edge-nodes and face-nodes numbering
       slighly differ from those used in the gmsh mesh generator when using high-order elements.  This difference is handled by the  msh2geo  mesh
       file converter (see msh2geo(1)).

IMPLEMENTATION
       const size_t dimension = 3;
       const Float  measure = Float(1.)/Float(6.);
       const size_t n_vertex = 4;
       const Float vertex [n_vertex][dimension] = {
	       { 0, 0, 0 },
	       { 1, 0, 0 },
	       { 0, 1, 0 },
	       { 0, 0, 1 } };
       const size_t  n_face = 4;
       const size_t face [n_face][3] = {
	       { 0, 2, 1 },
	       { 0, 3, 2 },
	       { 0, 1, 3 },
	       { 1, 2, 3 } };
       const size_t  n_edge = 6;
       const size_t edge [n_edge][2] = {
	       { 0, 1 },
	       { 1, 2 },
	       { 2, 0 },
	       { 0, 3 },
	       { 1, 3 },
	       { 2, 3 } };

SEE ALSO
       msh2geo(1)

rheolef-6.1							    rheolef-6.1 					     tetrahedron(7rheolef)