1 Some Physics
--------------

This program is a simple simulation of the phenomena of spontaneous
magnetization.  The idea is taken from [1].

A field of magnetic dipoles is randomly setup.  The dipoles initialy show
up or down with a certain probability.  When the simulation starts, a
dipole is picked out and only if the sum over its four neighbour spins is
zero, it is flipped.  The used theorie tells, that there is no change in
overall energy in this case, but the overall magnetiztion is changed.

If you start with a spin-distribution of 50% showing up, you get the state
at very high temperatures with nearly zero magnetization.  If you change
the distribution to about 8% showing up (=92% showing down), you are at the
curie-point. Over 8%, magnetization will disapear slowly, below 8% it stays
finit, this is the spontaneous magnetization.




2 The Program
-------------

You can start the program from workbench with standart arguments or from
CLI with your arguments. CLI-Usage is:

   Magnet [-w width] [-h height] [-l level] [-?] [?]

Width and Height are the outer window sizes (use -1 for full size).  Level
is the inital spin distribution percentage in 1/1000 (range 0-1000).  Set
level to 500 for equal distribution or to 80 for curiepoint.

There is also a binary version for 68040: Magnet040.




3 The Source
------------

The program is written in C++ with SAS-C 6.55. The source code is included
and absolutely PUBLIC DOMAIN, as far as it is not used for military
purposes!

The source contains a simple C++ window-class, that might be usefull for
programmers.




4 The Author
------------

Georg Pfundt, Physics student, Universität Karlsruhe, Germany
E-Mail: gp@ict.fhg.de
Homepage till Dec. 1996: http://fphvax.rz.uni-karlsruhe.de/~pfundt
Homepage will move to: http://www.rz.uni-karlsruhe.de/~ut53




Literature
----------
[1] Dietrich Stauffer; "Theoretische Physik :  ein Kurzlehrbuch und
    Repetitorium", Springer Verlag Berlin, Heidelberg, New York, 1989.
    ISBN 3-540-50697-7 (Berlin ...),  ISBN 0-387-50697-7 (New York ...)

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-rw-r--r--   187/531       270     628  43.0% -lh5- 05c1 Oct 15  1996 SpontiMag10.info
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-rw-r--r--   187/531      2485    5714  43.5% -lh5- e34f Oct 15  1996 SpontiMag10/Magnet.cpp
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-rw-r--r--   187/531       263     454  57.9% -lh5- 0ce9 Oct 15  1996 SpontiMag10/SCoptions
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-rw-r--r--   187/531      1194    2277  52.4% -lh5- e5d4 Oct 15  1996 SpontiMag10/spontimag10.readme
-rw-r--r--   187/531       229     472  48.5% -lh5- 69be Oct 15  1996 SpontiMag10/spontimag10.readme.info
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