[Gmsh] High-order quads
Geordie McBain
gdmcbain at freeshell.org
Tue Mar 15 23:31:28 CET 2011
2011/3/16 Martin Vymazal <martin.vymazal at vki.ac.be>:
> Hello,
>
> could someone please tell me what is the local node numbering for P3
> quadrilaterals in gmsh? Looking in the documentation, it seems that P3 quads
> are not supported, but using "-order 3" I still can generate a mesh with
> elements which look like this:
>
> x---x---x---x
> | |
> x x x x
> | |
> x x x x
> | |
> x---x---x---x
>
> Can you please tell me what are the local node numbers?
Hello. I found this ASCII diagram in a C comment on lines 317--332 of
Geo/MQuadrangle.h.
/*
* MQuadrangle
*
* 3--3+3E-...--4+2E--2
* | | E = order - 1;
* | | N = total number of vertices
* 4+3E 3+2E
* | | Interior vertex numbers
* ... 4+4e to N-1 ... for edge 0 <= i <= 3: 4+i*E to 3+(i+1)*E
* | | in volume : 4+4*E to N-1
* 3+4E 4+E
* | |
* | |
* 0---4--...---3+E---1
*
*/
I think it should specialize to the case you want for E=2, so that,
for example, along the bottom we'd have 0, 4, 5, 1.