help with GetDP needed

Christophe Geuzaine Christophe.Geuzaine at ulg.ac.be
Tue Dec 7 09:14:25 CET 1999


Samuel Kvasnica wrote:
> 
> > > and many 'Unknown variable: nan' parser errors after trying to open generated file with gmsh.
> > > Any idea ?
> >
> > No, this is strange.
> 
> this problem still remains. It appeared after I started to use VolAxi. .pos file for Az really
> contains
> some NaN's. B and H makes no problems, just Az.  Could these be some discontinuities on the axis ?
> Maybe axis should be excluded from postprocessing someway ?

Yes, I'll think about it.

> 
> > No, I didn't implement higher order interpolation stuff yet. But why do
> > you need such a fine mesh ? This magnetostatic problem is very simple,
> > and besides geometrical singularities, there are no discretisation
> > problems in it. So, below a certain threshold, mesh refinement (or
> > higher interpolation) will just smooth the answer and not get you closer
> > to the theoretical value. If you absolutely want to have 'ultra-smooth'
> > field patterns, you could as well perform a laplacian smoothing to the
> > solution inside the domain as a post-processing step...
> 
> Well, look at the attached picture, there are still some ugly steps of the order of ~1mm.
> As you see symetry is very good - these 2 curves are the same curve mirrored around
> z=0. Actually what I need is not finer mesh but - computing on rectangular mesh or a
> better interpolation in postprocessing or a laplacian smoothing as you said. Is there such
> a possibility to do it during postprocessing directly with getdp ?
> 

No, I think the best is to apply such a treatment on the grid you
obtained after post-processing (so it's trivial to implement, e.g. in a
small script). 

BTW, you should use the symmetry to reduce the size of your problem by a
factor 2...

(I didn't get the attached image)

-- 
Christophe Geuzaine

Tel: +32-(0)4-366.37.10    mailto:Christophe.Geuzaine at ulg.ac.be
Fax: +32-(0)4-366.29.10    http://www.montefiore.ulg.ac.be/~geuzaine/