Eucsyms is an interactive viewing tool for exploring the
crystallographic symmetries of three dimensional Euclidean space.  It
is an application of the general purpose viewer geomview.  The method
is to use objects to infer each kind of symmetry.  The objects used
are arbitrary (anything acceptable to geomview) and the symmetries
displayed (via the objects) are chosen by the user.  Intuitively what
eucsyms does is allow the user to build hypothetical crystals, by
adding atoms whereever s/he wants them in space, subject to the
restriction that their placement conforms to a chosen symmetry.  

Eucsyms was made by Olaf Holt in 1990 and updated at the beginning of
1992, with additional help from Charlie Gunn, who contributed the
dirdom code, and Stuart Levy, who explained OOGL.  Mark Phillips made
minor modifications in the process of installing it on the Geometry
Center IRISes.  Tamara Munzner updated it to use geomview instead of
MinneView in spring 1992. (The current version does not work with
Dirichlet domains yet.)  Questions can be directed to the author
(holt@geom.umn.edu), and comments are appreciated. The author's
permanent address is
	3329 14th Ave S
	Mpls MN 55407

This edition of eucsyms should be a working copy: it might fail
occasionally, but the snags should not be critical to its intended
operation.  

To use eucsyms, you will need three types of files:
    a)	Files from this directory:

	  Source code:
	    Ooglcalls.c		  filecalls.c
	    arrays.c		  glgcalls.c
	    callbacks.c		  latdiffs.c
	    controlpanel.c	  linalg.h
	    dirdomcalls.c	  newthor.c
	    eucsyms.c		  controlpanel.fd

	  Data: 
	    (these files are in the geomview default distribution
	     but are included here just in case)
	    xwyezed.vect
	    230data.[,.Conway,.lat,.names]
	    cube2.off

	  Documentation:
	    eucsyms.man  (a man page)

    b)	Files for the OOGL library for geomview (version 1.02). 

	Note that eucsyms uses the GEOMDATA variable, which is set by
	geomview. It assumes that 230data.* are in GEOMDATA/groups and
	xwyezed.vect and cube2.off are in GEOMDATA/geom.

    c)	Files for the Forms library of Mark Overmars (version 2.0).

	libforms.a and forms.h are included with the geomview source
	distribution.
	    
To compile the program, use the Makefile provided-- simply make!

Further information on space groups is available from several sources;
one I used was "Geometric Symmetry", by E. H.  Lockwood and R. H.
Macmillan, published by the Cambridge University Press in 1978.
