[Gmsh] Thank you & possible Gmsh have memory leak issues?

[CEM ALBUKREK]

Dear Prof. Christophe Geuzaine:

First I would like to express my great appreciation of the work you have
done with Gmsh, which I have been experimenting with as a CFD consultant.
The package is very capable, concise and user friendly - I think it has
non-academic use potential and I would recommend it to my colleagues. Now
coming to the "headache" portion of my message, I would like to get some
feedback from you on the below questions, which were triggered by seemingly
excessive memory usage in volume meshing.

Background:

I have a test case consists of ~200,000 facets of STL closed-solid surface
enclosed in a slightly offset rectangular box, built parametrically using
GMSH geo language. So I am trying to mesh the volume between the STL surface
and the rectangular box. The 1D and 2D meshing works fine on the outer
surface. Finally in the 3D step, for tetgen meshing, RAM usage grows
monotonously past 3gigs and finally the process exits with a memory
allocation error.

To see if the problem was with the STL mesh quality or simply the size, I
setup a similar problem with a sub-section of the STL geometry, such that I
have 130,000 facets. Again the memory usage grew significantly, past 2gigs,
but I was able to obtain a volume mesh before the memory limit was reached.

So, 132,000 STL surface facets results in 15.8million tetrahedra and
consumes about 2.3 gig RAM.

Questions:

1) Are the above memory requirements expected or are they indicative of a
memory leak?

2) What's your recommended upper limit for STL facet count to obtain a
volume mesh with ~4gig ram? (In here I am not so concerned about
performance, but rather the ability to obtain a volume mesh)

3) If the memory requirements make sense to you,  are there parameters that
I can adjust to reduce memory requirements? (I have already increased the
characteristic length to an extreme to minimize the surface facet count on
the outer box)

4) How can I help to address the memory management issue - I have the source
code and I am able to compile it on linux?

As a separate but somewhat related issue:

5) Why did you remove the experimental STL re-mesh feature of Gmsh v1.61. It
seems to be a very useful tool, I am curious if there are any specific
problems with it?

Thank you again for the great value you make available for free. I hope to
use and help improve Gmsh, so that medium size, but realistic problems can
be handled in the realm of CFD.

Sincerely yours,

-- 
Cem Albukrek, Ph.D.
Senior Aerodynamics Consultant,
Software Product Manager
Tel: (857) 234-1035
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