[Gmsh] gmsh/bamg - use of bgm posfiles???

[trophime]

On Fri, 2012-01-27 at 17:53 +0100, Christophe Geuzaine wrote:
> On 27 Jan 2012, at 17:46, trophime wrote:
> 
> > On Fri, 2012-01-27 at 17:28 +0100, Cécile CD. DAVERSIN wrote:
> >>        Hi
> >>        I would like tu use bamg algo to get an anisotropic mesh.
> >>        I wish to use a metric as a background mesh and generate the
> >>        anistropic mesh from it :
> >> 
> >>        gmsh -2 geofile  -algo bamg -bgm metrics.pos
> >> 
> >> 
> > 
> > Using a bgm in this context does not work.
> > 
> > *) The bgm file is always treated as "isotropic" :
> > 
> > in void PostViewField::operator() (double x, double y, double z,
> > SMetric3 &metr, GEntity *ge=0) :
> > virtual bool PostViewField::isotropic () const always return true
> > as v is null!
> > 
> > *) the bgm is not taken into account. In fact it tries to 
> > get a metric from some """formula""" (see BGM_MeshMetric) 
> > just like in  http://www.geuz.org/pipermail/gmsh/2012/006970.html
> > 
> > It would be really great if we can use bgm metrics...
> > 
> 
> Hi Christophe - I coded this in a hurry and did not have time to test it... I've committed a small patch: can you try again?

Ok now PostViewField::isotropic () returns the "right" value in case of
anisotropic metric bgm. Thanks

However my metrics seems not not to be read properly.
I don't know why yet.

Moreover I have question :
when using metrics you adapt the mesh using the intersection of the
metric M1 read from the bgm and a "default" isotropic metric M2 derived
from lc mesh characteristics. 
* Why do you use the max eigenvalues of M1 and M2 instead of the
eigenvalues of M1^{-1} M2?
* Is it possible to just use M1?

C. 

> 
> > Best
> > C
> > 
> > 
> > 
> > 
> > 
> > 
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