[95] in mathematical software users group
Matlab files for nD processing
daemon@ATHENA.MIT.EDU (dsodicks@Athena.MIT.EDU)
Sat May 22 17:55:18 1993
From: dsodicks@Athena.MIT.EDU
To: msug@MIT.EDU
Date: Sat, 22 May 93 17:54:52 EDT
Thank you all for your suggestions on multidimensional array
processing, etc..
For those who were wondering what sorts of multidimensional tasks
are called for, the application I have in mind is as follows:
I am trying to model the dynamics of a 3-dimensional lattice of mutually
interacting nuclear spins, and I need to keep track of the net local magnetic
field and the spin orientation (plus several of its time derivatives) at each
point in the lattice. In principle, I could store this information in an
ordered series of 2D matrices, but it is much more convenient to use
a realistic object with 3 indices. Also, for a large lattice,
3D FFT/convolution techniques become quite useful in calculating the net
local field (summing at each spin site the fields due to all the other
spins in the lattice). My physical system can itself be represented as a
three-dimensional matrix, thus 3D matrix operations are natural to the problem.
One user was kind enough to forward to me a package of Matlab M files
for multidimensional matrix processing (including matrix initializations,
component extractions, index permutations, and nD FFT's). The package
is contained in a 50k shell archive, thus I am reluctant to post it to
the group unless there is sufficient interest (I suppose 50k isn't really
that much, but I'll be circumspect anyway). If anyone is interested
in getting a copy of the package, send me mail (dsodicks@athena.mit.edu),
and I'll either send you a copy, or post the whole darn thing.
Sincerely,
Dan Sodickson
P.S. Recently, I also learned of a free numerical analysis package called
Octave which uses much of the syntax and includes a subset of the built-in
functions of Matlab. Those who don't have access to Matlab and are interested
can get it via anonymous ftp from ftp.che.utexas.edu .
