Re: [Getfem-users] DOFs of a node

[Roman Putanowicz]

On Sun, Jul 18, 2010 at 01:24:41PM +0200, Konstantinos Poulios wrote:
> Hi,
> 
> this is the answer Yves had given to a similar question of mine:
> 
> > Normally, you should only work with dof number, not point number.
> > A point is a vertex of an element in the mesh. You do not have necessary
> > a correspondance between vertex of the mesh and dofs (think to non-coformal
> > P1 for instance).
> 
> I hope it helps. Something else that I consider as relevant is a
> snippet given in:
> 
> bgeot_kdtree.h
> see:
> http://download.gna.org/getfem/doc/getfem_reference/bgeot__kdtree_8h_source..html
> 
> which shows a way to implement a mapping between dofs and point numbers.
> 
> In my case I had finally found a solution which didn't require this mapping..
> 

Thanks for your answer. I have asked that question because in domains
for truss or frame structures it is customary and convenient to select
DOFs via nodes. Those are however some special cases so building a respective
mapping should be possible.  I agree that in general case and for more
dimensional domains working with mesh nodes can be problematic.

This issue is probably worth a short notice in the documentation 
especially for beginners in FEM.

Regards,

Roman

-- 
Roman Putanowicz, PhD  < address@hidden  >
Institute for Computational Civil Engng (L-5)
Dept. of Civil Engng, Cracow Univ. of Technology
www.l5.pk.edu.pl, tel. +48 12 628 2569, fax 2034