[Edu-sig] Basic dictionary question

[John Zelle]

Kirby,

Do you have a left and right stereo pair on that rendering? I just can't 
make heads or tails of it w/o true 3D :-)

--John

Kirby Urner wrote:
>>I'll post again when I have more research behind me and either a solution
>>or concrete frustration in sight -- not before.
>>
>>Kirby
> 
> 
> OK, I've got a solution working.  Here's an interim result:
> http://www.4dsolutions.net/satacad/pythonicmath/connectorstudy2.jpg
> 
> Notice how the zigzag metal bands connect jade icosahedra and don't clutter
> the unit cell otherwise, i.e. no extra tabs that don't go through bridge
> points.
> 
> I ended up using a feature specific to my vector class:  the bridge points
> all had 4-tuple signatures with floats = multiples of 1/2.  So I used a
> little round and chop function that appears to have worked:
> 
>     @staticmethod
>     def _mktuple(qray):
>             thecoords = qray.coords
>             thelist = []
>             for c in thecoords:
>                 t = float(str(round(c,5))[:4])
>                 thelist.append(t)
>             return tuple(thelist)
> 
> The 4-tuples are all positive, even in xyz octants w/ negatives, thanks to
> quadray vector algebra.  I stuffed 'em into a dict like this:
> 
> def add2pairs(adict, thekeys):
>     for newkey in thekeys:
>         adict[newkey] = adict.get(newkey,0) + 1
>     return addict
> 
> ...then permitted only those with value = 2 to render.
> 
> Special thanks to Guido and Scott for helping me grabble with this issue.
> 
> Kirby
> 
> Note:
> 
> Here's the stuff photographed in time/size (vs. rendered):
> http://www.4dsolutions.net/satacad/pythonicmath/lanahan_artifact.jpg
> (photo by Dave Ulmer @ Linus Pauling House, wwwanderers.org)
> 
> 
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> 

-- 
John M. Zelle, Ph.D.             Wartburg College
Professor of Computer Science    Waverly, IA
john.zelle at wartburg.edu          (319) 352-8360