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From: jpw@uclachem.UUCP (James Wilkinson)
Newsgroups: sci.physics,comp.graphics
Subject: Internal representation of 3-D harmonic structures.
Keywords: dynamics, hll representations
Message-ID: <673@uclachem.UUCP>
Date: 5 Sep 89 06:13:51 GMT
Organization: UCLA Chemistry Department
Lines: 22

I would like some opinions regarding the best, or most efficient
data structure, in which one would store 3-d coordinates for a
dynamic lattice of points.  Such a structure should be able to
account for the different crystal lattice types, such as hexagonal
close packing (hcp), ccp, fcc, bcc and so forth.  Starting with
such a structure developed at run-time, one would allow harmonic
motion to occur in the 3-d structure.

I can use graph theory to compose an appropriate structure, but
this would not be efficient since I would spend a lot of time
traversing my trees.  If I use arrays, things are a little messy
since you don't know the 3-d periodic structure in advance, nor
its size (and I'm trying to stay away from FORTRAN), not to mention
the tempation to make the array 1-d for vector processing purposes.

Thus, I wish for a way to dynamically create a 3-d array of points
without predeterming the periodic symmetry which is somewhat effic-
ient and readable.  Thanks to anyone who can wade through my request
and suggest something.

JaW
james@abby.chem.ucla.edu