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From: S. B. Gray on 6 Aug 2010 06:59
I'm pretty sure that a few years ago I downloaded a function that Eric
W. wrote to compute the CH of some points in 3D. He intended it to be a
temporary solution because Mathematica has CH only for 2D. I can't find it now
and I need it. I have only a dozen or so random points and don't need
super speed.

Steve Gray

From: Yves Klett on 7 Aug 2010 01:32
This seems to work, watch out for: ?*`Convex*

pts = RandomReal[{-1, 1}, {100, 3}];
hull = ComputationalGeometry`Methods`ConvexHull3D[pts];
Graphics3D[{PointSize[Large], Point[pts], White, Opacity[0.5],
hull[[1]]}]

HTH,
Yves

Am 06.08.2010 12:59, schrieb S. B. Gray:
> I'm pretty sure that a few years ago I downloaded a function that Eric
> W. wrote to compute the CH of some points in 3D. He intended it to be a
> temporary solution because Mathematica has CH only for 2D. I can't find it now
> and I need it. I have only a dozen or so random points and don't need
> super speed.
>
> Steve Gray
>

From: Christopher Henrich on 9 Aug 2010 05:14
In article <i3gptp$35i$1(a)smc.vnet.net>,
"S. B. Gray" <stevebg(a)ROADRUNNER.COM> wrote:

> I'm pretty sure that a few years ago I downloaded a function that Eric
> W. wrote to compute the CH of some points in 3D. He intended it to be a
> temporary solution because Mathematica has CH only for 2D. I can't find it
> now
> and I need it. I have only a dozen or so random points and don't need
> super speed.
>
> Steve Gray

I submitted a set of packages for multidimensionl convex polyhedra to
the Wolfram Library Archive:
<http://library.wolfram.com/infocenter/MathSource/7034/>
I would advise that you convert your coordinates to rational numbers.
Then I think it would handle the problem you describe with satisfactory
speed.

--
Christopher J. Henrich
chenrich(a)monmouth.com
http://www.mathinteract.com
"A bad analogy is like a leaky screwdriver." -- Boon

From: Arturas Acus on 10 Aug 2010 03:55
And I remember that IMTEK package for finite element calculations has
mathematica interface to very fast
convex hull compiled code in arbitrary dimension.

Just ask google for IMTEK and Mathematica.


On Mon, 9 Aug 2010, Christopher Henrich wrote:

> In article <i3gptp$35i$1(a)smc.vnet.net>,
> "S. B. Gray" <stevebg(a)ROADRUNNER.COM> wrote:
>
>> I'm pretty sure that a few years ago I downloaded a function that Eric
>> W. wrote to compute the CH of some points in 3D. He intended it to be a
>> temporary solution because Mathematica has CH only for 2D. I can't find it
>> now
>> and I need it. I have only a dozen or so random points and don't need
>> super speed.
>>
>> Steve Gray
>
> I submitted a set of packages for multidimensionl convex polyhedra to
> the Wolfram Library Archive:
> <http://library.wolfram.com/infocenter/MathSource/7034/>
> I would advise that you convert your coordinates to rational numbers.
> Then I think it would handle the problem you describe with satisfactory
> speed.
>
> --
> Christopher J. Henrich
> chenrich(a)monmouth.com
> http://www.mathinteract.com
> "A bad analogy is like a leaky screwdriver." -- Boon
>
>

From: Oliver Ruebenkoenig on 11 Aug 2010 04:46
Hi,

On Tue, 10 Aug 2010, Arturas Acus wrote:

> And I remember that IMTEK package for finite element calculations has
> mathematica interface to very fast
> convex hull compiled code in arbitrary dimension.

It's up to dimension 9 and uses QHull.

>
> Just ask google for IMTEK and Mathematica.

http://portal.uni-freiburg.de/imteksimulation/downloads/ims

Once you install it, the QHull interface is in Add-Ons -> IMTEK

IMTEK->Interfaces->QHull

As an alternative for 3D, you could also use the TetGen interface for th a
hull computation. In both cases you'd need to install additional
software. Either QHull or TetGen.

Hope this helps,
Oliver

>
>
> On Mon, 9 Aug 2010, Christopher Henrich wrote:
>
>> In article <i3gptp$35i$1(a)smc.vnet.net>,
>> "S. B. Gray" <stevebg(a)ROADRUNNER.COM> wrote:
>>
>>> I'm pretty sure that a few years ago I downloaded a function that Eric
>>> W. wrote to compute the CH of some points in 3D. He intended it to be a
>>> temporary solution because Mathematica has CH only for 2D. I can't find it
>>> now
>>> and I need it. I have only a dozen or so random points and don't need
>>> super speed.
>>>
>>> Steve Gray
>>
>> I submitted a set of packages for multidimensionl convex polyhedra to
>> the Wolfram Library Archive:
>> <http://library.wolfram.com/infocenter/MathSource/7034/>
>> I would advise that you convert your coordinates to rational numbers.
>> Then I think it would handle the problem you describe with satisfactory
>> speed.
>>
>> --
>> Christopher J. Henrich
>> chenrich(a)monmouth.com
>> http://www.mathinteract.com
>> "A bad analogy is like a leaky screwdriver." -- Boon
>>
>>
>
>

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