Re: Release candidate for Qhull 2012.1

[Ben Abbott]

On Jan 29, 2012, at 10:42 PM, Brad Barber wrote:

> At 08:50 PM 1/29/2012, Ben Abbott wrote:
> 
>> On Jan 29, 2012, at 8:46 PM, Dmitri A. Sergatskov wrote:
>> 
>>> On Sun, Jan 29, 2012 at 7:38 PM, Ben Abbott <address@hidden> wrote:
>>> 
>>>> On Matlab ...
>>>> 
>>>> cube = [0 0 0;1 0 0;1 1 0;0 1 0;0 0 1;1 0 1;1 1 1;0 1 1];
>>>> [h, v] = convhulln (cube);
>>>> 
>>>> h =
>>>> 
>>>>    3     4     2
>>>>    2     4     1
>>>>    6     2     1
>>>>    5     6     1
>>>>    4     8     1
>>>>    8     5     1
>>>>    7     3     2
>>>>    6     7     2
>>>>    7     4     3
>>>>    7     8     4
>>>>    7     6     5
>>>>    8     7     5
>>>> 
>>>> 
>>>> v =
>>>> 
>>>>    1
>>>> 
>>>> [h, v] = convhulln (cube, {'Qt'})
>>>> 
>>>> h =
>>>> 
>>>>    3     4     2
>>>>    2     4     1
>>>>    6     2     1
>>>>    5     6     1
>>>>    4     8     1
>>>>    8     5     1
>>>>    7     3     2
>>>>    6     7     2
>>>>    7     4     3
>>>>    7     8     4
>>>>    7     6     5
>>>>    8     7     5
>>>> 
>>>> v =
>>>> 
>>>>    1
>>>> 
>>>> I get the same with Octave (tip below) on MacOSX 10.7.2 (Lion).
>>>> 
>>>> $ hg tip
>>>> changeset:   14282:b4d7de953066
>>>> tag:         tip
>>>> user:        Michael Goffioul <address@hidden>
>>>> date:        Sun Jan 29 12:53:05 2012 +0000
>>>> summary:     Export more required symbols [Win32].
>>>> 
>>>> Does Fedora really return a 6x4 matrix for the first test?
>>>> 
>>>> Ben
>>> 
>>> octave:1> cube = [0 0 0;1 0 0;1 1 0;0 1 0;0 0 1;1 0 1;1 1 1;0 1 1];
>>> octave:2> [h, v] = convhulln (cube);
>>> octave:3> h
>>> h =
>>> 
>>>  4   1   2   3
>>>  5   6   2   1
>>>  8   5   1   4
>>>  6   7   3   2
>>>  7   8   4   3
>>>  8   7   6   5
>>> 
>>> Fedora 16 x86_64, octave 3.6.0, qhull 2003.1
>>> 
>>> Dmitri.
>> 
>> Using qhull version < 2011 I got the same thing.
>> 
>> Doesn't this result imply that the 6 faces of the cube are being returned 
>> and not the 12 triangulated faces ?
>> 
>> Given the default option is "Qt" shouldn't the result be triangles?
>> 
>> Ben
> 
> Note the version from Fedora.  It is using qhull 2003.1 which introduced 
> option 'Qt'.  
> 
> My guess is that the Fedora build did not set 'Qt' as the default option 
> list.  
> 
> All targets for Octave should use the same default option list.
> 
>                                        --Brad 

What doesn't make sense to me is that Octave sets it's on defaults, and in this 
instance the default is "Qt". With qhull < 2011 I get the Fedora result.

Can someone on Fedora (specifically qhull-2003) try ...

         cube = [0 0 0;1 0 0;1 1 0;0 1 0;0 0 1;1 0 1;1 1 1;0 1 1];
        [h, v] = convhulln (cube, {"Qt", "FO"})

... and tell us what the result is ?

Ben