about Unstructured Meshes

[Matthew Knepley]

On 3/5/07, li pan <li76pan at yahoo.com> wrote:
> I always need complex geometry of different curves and
> distorted surface. In my case, I found, Netgen
> generates much better mesh. Just out of my curiousity.
> How complicated is your geometry?

Thats odd. I have never had netgen give me a better mesh.

   Matt

> see u
>
> pan
>
>
> --- Matthew Knepley <knepley at gmail.com> wrote:
>
> > On 3/4/07, li pan <li76pan at yahoo.com> wrote:
> > > hi Matt,
> > > have you ever evaluated Tetgen? How do you think
> > about
> > > the quality of the 3D mesh it generated?
> >
> > I have heard anecdotes about failures for
> > complicated geometry,
> > however I have never had a problem. The quality is
> > pretty good.
> > Gary Miller has shown that the number of tets
> > generated is way
> > too high, but I know of no better implementation.
> >
> >    Matt
> >
> > > see u
> > >
> > > pan
> > >
> > >
> > > --- Matthew Knepley <knepley at gmail.com> wrote:
> > >
> > > > On 3/2/07, Jianing Shi <jianings at gmail.com>
> > wrote:
> > > > > Well, let me rephrase my question.  So the
> > mesh
> > > > support in PETSc
> > > > > already includes the functionality of
> > partitioning
> > > > meshes, I guess,
> > > > > using ParMetis, is that the case?  Something
> > that
> > > > an end user need to
> > > > > worry about is really how to generate a mesh
> > that
> > > > is tailored towards
> > > > > his/her application.
> > > >
> > > > It can use a range of partioners, like Chaco for
> > > > instance.
> > > >
> > > > > I am trying to write a library on top of PETSc
> > > > meshes that will
> > > > > generate meshes according to some
> > neurophysiology.
> > > >  I would like to
> > > > > know what are the mesh generate softwares out
> > > > there that will
> > > > > interface nicely with PETSc, or if it makes
> > sense
> > > > for me to write my
> > > > > own?  Just would like to understand more about
> > the
> > > > data structure in
> > > > > the PETSc ALE::Mesh classes.  Is there any
> > > > tutorial out there apart
> > > > > from looking at the source code in the mesh
> > > > directory?
> > > >
> > > > 1) No, it makes no sense for you to write a mesh
> > > > generator
> > > >
> > > > 2) In 2D, Triangle. In 3d, the only free things
> > are
> > > > TetGen and Netgen. I support
> > > >     TetGen. Hopefully, CMU will release its MG
> > soon.
> > > >
> > > > There is a tutorial on the website.
> > > >
> > > > > I am currently using the petsc-2.3.2-p3.  Is
> > there
> > > > any new
> > > > > functionality about meshes in the development
> > > > version?
> > > >
> > > > All the working stuff is in petsc-dev.
> > > >
> > > >   Matt
> > > >
> > > > > Jianing
> > > > --
> > > > One trouble is that despite this system, anyone
> > who
> > > > reads journals widely
> > > > and critically is forced to realize that there
> > are
> > > > scarcely any bars to eventual
> > > > publication. There seems to be no study too
> > > > fragmented, no hypothesis too
> > > > trivial, no literature citation too biased or
> > too
> > > > egotistical, no design too
> > > > warped, no methodology too bungled, no
> > presentation
> > > > of results too
> > > > inaccurate, too obscure, and too contradictory,
> > no
> > > > analysis too self-serving,
> > > > no argument too circular, no conclusions too
> > > > trifling or too unjustified, and
> > > > no grammar and syntax too offensive for a paper
> > to
> > > > end up in print. --
> > > > Drummond Rennie
> > > >
> > > >
> > >
> > >
> > >
> > >
> > >
> >
> ____________________________________________________________________________________
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> > >
> > >
> >
> >
> > --
> > One trouble is that despite this system, anyone who
> > reads journals widely
> > and critically is forced to realize that there are
> > scarcely any bars to eventual
> > publication. There seems to be no study too
> > fragmented, no hypothesis too
> > trivial, no literature citation too biased or too
> > egotistical, no design too
> > warped, no methodology too bungled, no presentation
> > of results too
> > inaccurate, too obscure, and too contradictory, no
> > analysis too self-serving,
> > no argument too circular, no conclusions too
> > trifling or too unjustified, and
> > no grammar and syntax too offensive for a paper to
> > end up in print. --
> > Drummond Rennie
> >
> >
>
>
>
>
> ____________________________________________________________________________________
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-- 
One trouble is that despite this system, anyone who reads journals widely
and critically is forced to realize that there are scarcely any bars to eventual
publication. There seems to be no study too fragmented, no hypothesis too
trivial, no literature citation too biased or too egotistical, no design too
warped, no methodology too bungled, no presentation of results too
inaccurate, too obscure, and too contradictory, no analysis too self-serving,
no argument too circular, no conclusions too trifling or too unjustified, and
no grammar and syntax too offensive for a paper to end up in print. --
Drummond Rennie