help with GetDP needed

[Christophe Geuzaine]

Samuel Kvasnica wrote:
> 
> Christophe Geuzaine wrote:
> 
> > Oups, yes, there is an another small error in the PostProcessing field:
> > you should give each postprocessing quantity the type of jacobian to use
> > in the interpolation.
> 
> O.k., now it works ! My simulation results improved much after this last jacobian fix.
> Especially
> electron trajectories in the field of first and last segment. I just don't understand why do I
> need
> to put  Jacobian Vol and not something like Jacobian VolAxi into PostProcessing. 

Maybe I made a mistake in my mail ? Anyway, you should give in the
PostProcessing the same jacobian method as in the Formulation. The name
refers to the name of the jacobian method : for example, it should be
'test' in this case (not 'Vol')

JacobianMethod {
  { Name test ;
    Case { { Region All ; Jacobian Vol ; } }
  }
)


> Another small
> problem: if I want to generate .pos files to view the results in gmsh, I'm getting am error:
> 
> Bad parameters for JacobianVolSphShell: Rint=0.35, Rext=0.45, R=0.45

Well, the radius computed by getdp is R=0.45, which is equal to Rext
(but R<Rext should hold, not R<=Rext). Just add a small quantity to the
Rext value, to assure the inequality.

> 
> and many 'Unknown variable: nan' parser errors after trying to open generated file with gmsh.
> Any idea ?

No, this is strange.

> 
> Well, another question: is it possible to add few more (or at least one more) base function(s)
> to
> function space ? I'd like to refine the result a little bit more - my last simulation shows
> that I'll need
> a grid with resolution of ~0.05mm. This makes me unhappy because simulation times will grow to
> ~ 1 week, but there's no other possibility...

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...

-- 
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/