[Gmsh] GMSH questions
Christophe Geuzaine
cgeuzaine at ulg.ac.be
Thu Jul 19 10:20:17 CEST 2007
idesbald van den bosch wrote:
> Well, can you try both GMSH 2.0.8 and 1.65 on the attached file
> containing only flat surfaces?
>
> For me:
> 1) GMSH 1.65, took 2 min 20 sec., 624 MB max mem
> 2) GMSH 2.0.8, took 16 min using MeshAdapt+Delauney, 147 MB max mem
With 2.0.8 and "-algo del2d" it takes 33 seconds and 147Mb on my laptop
(mesh contains 1.5 million triangles). Beware that "del2d" is
experimental and that the generated elements are oriented randomly.
>
> so the speed is degraded by a factor of 8 (bad), but the memory is
> divided by 4 (good).
>
> On the other hand, is the daily release available? where?
2.0.8 is pretty much in sync with the nightly release right now.
>
> Ides
>
> On 7/18/07, *Jean-Fran çois Remacle* <remacle at gce.ucl.ac.be
> <mailto:remacle at gce.ucl.ac.be>> wrote:
>
> idesbald van den bosch a écrit :
> > Hello dear GMSH users,
> >
> > I am a GMSH user since quite a while now, and I have a question
> > concerning the 2.0.x series. It seems that v2.0.X is much more
> > RAM-memory efficient than its v1.65 counterpart. Unfortunately it is
> > also much slower (~3 times from my limited experience).
> >
> The 2D mesh generator is slower, but I think it is more robust and
> enables to mesh general curved surfaces (NURBS ...).
> In the daily release, I have put back a classical isotropic delaunay
> that is much faster even than the v1.65 triangulator. Yet,
> it only works for planar surfaces for now, and for meshing the sphere
> (look at the attachement). When I'll find some time, I'll
> generalize this algo for general curved surfaces.
>
> Normally, the 3D algorithms are much faster and more robust that the
> ones of previous releases.
> > 1) does anyone have the same observation?
> > 2) is the slowness a necessary trade-off for memory efficiency?
> >
> No, it's just the algorithm.
>
> > Thanks
> >
> > Ides van den Bosch
> > Bilkent Computational Electromagnetics Lab
> > Bilkent, Ankara
> > Turkey
> >
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>
> --
> --------------
> Prof. Jean-François Remacle
> Department of Civil Engineering and
> Center for Systems Engineering and Applied Mechanics
> Université catholique de Louvain, Belgium
> Tel : +32 10 472082
> Fax : +32 10 472210
>
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--
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine