The old delaunay code (from the GMT project ) had an error and wasn't
usefull for other geometric operations. (voronoi diagramms, convex
Thats why, I looked for a library which has to be:
* GPL compatible
* cover at least delaunay triangulation, voronoi diagramms and fast
* relatively small
* written in C or C++
I think the qhull package  fits thats needs.
For the 'lawyers': could you check the license, is it indeed GPL
I have made a slimmed qhull package  which includes only the files
needed to build the library and an adapted makefile. If you want to look
at examples or the
documentation, please take the original package .
The first function which uses the qhull lib is delaunay. You can get a
tarball from my homepage .
My question to you (especially jwe): What do you think is the best way
to go on?
* Keep the qhull lib and the DLD functions separate from octave
* include the DLD-functions in octave and
check at the configure stage for a user installed libqhull.
* include both in octave
Kai Habel wrote:
> The old delaunay code (from the GMT project ) had an error and wasn't
> usefull for other geometric operations. (voronoi diagramms, convex
> hulls, ..)
> My question to you (especially jwe): What do you think is the best way
> to go on?
> * Keep the qhull lib and the DLD functions separate from octave
> * include the DLD-functions in octave and
> check at the configure stage for a user installed libqhull.
> * include both in octave
I think that a 'contrib' directory should be setup in Octave
distribution. Not for m script files, but for dll ones.
Individual script files are most of the time very specific, and often
replicate each others functionalities. A package, by contrary, deserves
its own subdirectory in the scripts directory; if supplied with
reasonable test functions, the package would represent only a minor
support overhead, even if the original author disappears from Octave
Including dll functions in Octave itself puts too much overhead in its
maintenance, so I think that they should not go into Octave core. The
exception would be generally useful functionalities, such as ATLAS, HDF,
plotting, sparse matrix support, etc.
Until now, contributions from users have been split among several sites,
including Octave source mailing lists:
Most of the "repository" sites had a very limited success, so I think
that, for dll functions, a 'contrib' directory in Octave distribution
would be helpful. With time, perhaps some mature functions could be even
incorporated into Octave core.
Those functions could be downloaded in tar format to an 'incoming' ftp
directory, and, after unpacking, the results of a plain 'make check'
would establish if the contribution would be accepted. With no
compromise for support. This could also be done through CVS, but I think
that it would imply more administrative burden.
That's a pity that some useful functions, contributed with the GNU
philosophy in mind, would be lost by lack of adequate support, so I
think that this initiative should be centralized and advertised through
Octave home page. Even if redirected for other site.
> For the 'lawyers': could you check the license, is it indeed GPL
qhull/REGISTER.txt says :
Dear User of Geometry Center Software:
We would like to find out how you are using our software. Think of
Geometry Center software as a new kind of shareware: you share your
science and successes with us, and we share our software and support
with you. The Geometry Center is funded by the National Science
Foundation, and it is important that we be able to report to NSF the
ways in which our software is being used.
If you use Geometry Center software, please send us a letter telling
us what you are doing with it.
We need to know:
(1) What you are working on - an abstract of your work would be
(2) What Geometry Center software you use.
(3) How that software has helped you, for example, by increasing
your productivity or allowing you to do things you could not do
before. In particular, if you feel that Geometry Center
software has had a direct bearing on your work, please tell us
We encourage you to cite the use of any Geometry Center software you
have used in your publications.
: That's a pity that some useful functions, contributed with the GNU
: philosophy in mind, would be lost by lack of adequate support, so I
: think that this initiative should be centralized and advertised through
: Octave home page. Even if redirected for other site.
I agree completely, and I think that site could be octave.sourceforge.net.
It appears that this site is in limbo, but would be appropriate for ongoing
development of non-Octave but compatbile components, and certainly with the
idea that time-proven etc. contributions might, over time, be incorporated
into the Octave distribution itself.
SourceForge is ideal because it promotes the GNU philosophy, and supports
networked development via CVS and mailing list facilities, free of charge.
I'm still getting things into full gear with matlinks.net, and in a month or
so will probably be prepared to start translating all those matlab toolboxes
into octave. I believe those translations would be appropriate for
octave.sourceforge.net when they are not yet ready for inclusion with Octave
proper. I hope we can collectively "revive" activity at
octave.sourceforge.net with this prupose in mind. Paul and John have both
expressed interest in this idea, but it seems to be a matter of someone
taking responsibility for that site and "re-activating" it.
Great idea, in any case. If there's anything you'd suggest I can do to help
at matlinks.net, I'm completely open to such suggestions!
>> For the 'lawyers': could you check the license, is it indeed GPL
> qhull/REGISTER.txt says :
>Dear User of Geometry Center Software:
>We would like to find out how you are using our software. Think of
>Geometry Center software as a new kind of shareware: you share your
>science and successes with us, and we share our software and support
>with you. The Geometry Center is funded by the National Science
>Foundation, and it is important that we be able to report to NSF the
>ways in which our software is being used.
>If you use Geometry Center software, please send us a letter telling
>us what you are doing with it.
> So the best is probably to ask them if they mind having qhull
>bundled with octave. They might be happy if it were.
However, registering is not actually a requirement of the license.
The license itself is freer than the GPL. If you distribute a modified
version, you only have to say where to obtain the original, you do not
actually have to distribute the modified source.
This software includes Qhull from The Geometry Center. Qhull is
copyrighted as noted above. Qhull is free software and may be obtained
via anonymous ftp from geom.umn.edu. It may be freely copied, modified,
and redistributed under the following conditions:
1. All copyright notices must remain intact in all files.
2. A copy of this text file must be distributed along with any copies
of Qhull that you redistribute; this includes copies that you have
modified, or copies of programs or other software products that
3. If you modify Qhull, you must include a notice giving the
name of the person performing the modification, the date of
modification, and the reason for such modification.
4. When distributing modified versions of Qhull, or other software
products that include Qhull, you must provide notice that the original
source code may be obtained as noted above.
5. There is no warranty or other guarantee of fitness for Qhull, it is
provided solely "as is". Bug reports or fixes may be sent to
[hidden email]; the authors may or may not act on them as