From help-octave-request at bevo dot che dot wisc dot edu Fri Dec 19 16:06:41 2003
Subject: Re: ...interesting...
From: Paul Kienzle <pkienzle at jazz dot ncnr dot nist dot gov>
To: Przemek Klosowski <przemek at jazz dot ncnr dot nist dot gov>
Cc: help-octave at bevo dot che dot wisc dot edu
Date: Fri, 19 Dec 2003 17:05:18 -0500

On Fri, Dec 19, 2003 at 03:36:20PM -0500, Przemek Klosowski wrote:
> I ran the example from the guy for whom qhull coredumps on my
> octave 2.1.34 with octave-forge from Nov 02 on Lintel:
> 
>       ......
>     >       7.378 125.8 78.648553
>     >       7.378 129.5 78.241684 ]  ;
>     octave:3> 
>     octave:3>  X = T(:,1) ;
>     octave:4>  Y = T(:,2) ;
>     octave:5>  A = X + Y ; ## stupid
>     octave:6>  delaunay(A,X) ; # works
>     octave:7>  delaunay(X,Y) ; # doesn't work

For now use the following:

	delaunay(X,Y,'QJ')

The option 'QJ' joggles the inputs so that all facets are simplicial.
Without the 'QJ' option, some facets will have higher dimension than
others, and cause a crash.  

The QHull author recommends against 'QJ' because it is inaccurate. 

See the discussion on octave-dev at lists dot sf dot net:

http://sourceforge.net/mailarchive/forum.php?thread_id=3506293&forum_id=4874

for more detail than you probably want as we (they?) redefine the
interface to make use of all the information available from
QHull.

Paul Kienzle
pkienzle at users dot sf dot net



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