Cactus Code Thorn Exact
Authors : Carsten Gundlach initially, plus many other authors.
Maintainer : Jonathan Thornburg <jthorn@aei.mpg.de>
CVS info : $Header$
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Purpose of the thorn
====================
The initial purpose of this thorn was the comparison of numerical
spacetimes against exact solutions. One particular solution,
the boost-rotation-symmetric spacetimes, was the first application.
Later, the thorn developed as a reservoir for a variety of exact spacetimes,
some of them in different coordinate systems, and even some non-Einstein
spcetimes. All of these exact spacetimes have been found useful for
testing different aspect of the code. Since mamy different people have
contributed to this thorn by adding new exact solutions, you should expect
many different styles of coding here.
For more details see the comments in the param.ccl file, and the
documentation in the directory doc. For instructions on how to add
a new model, see doc/how_to_add_a_new_model.
Note that the June 2002 revisions to this thorn included renaming
most of the parameters. The perl script par/convert-par.pl will
convert old parameter files to use the new names, renaming the old
parameter files to ".par.bak" as backups.
Compilation
===========
On some systems (notably the AEI Xeons using the Intel compilers) this
thorn only compiles if you use the Cactus (perl) preprocessor, i.e. you
need to configure with
gmake foo-config CPP='$${PERL} $${CCTK_HOME}/lib/sbin/cpp.pl'
(along with any other configuration options), or put the line
CPP=$${PERL} $${CCTK_HOME}/lib/sbin/cpp.pl
in your ~/.cactus/config or other Cactus options file.
[Note by Erik Schnetter, 2005-05-15: The adivce above is outdated and
incorrect. This issue is also treated in the Cactus FAQ. Read it for
more information.]
This thorn is mostly written in Fortran 77, with a few files in C
and Fortran 90. At present Fortran 90 is only used for the "arbitrary slice"
option (see the thorn guide for details). If this option isn't needed,
then by changing a single line in src/include/Exact.inc (see the comments
there for details) you can #ifdef-out the Fortran 90 code, allowing the
rest of this thorn to be compiled on a system with no Fortran 90 compiler
available.
Copyright
=========
As noted above, this code has been hacked on by many different people,
so its' copyright and licensing status is somewhat unclear.
Here is a (incomplete) list of authors and their wishes:
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Many of the individual metrics (you can find them by grepping in the
header comments in the src/metrics/ directory) are
copyright (C) 2000-2003 by Dumitru "Mitica" Vulcanov <vulcan@aei.mpg.de>
This code is under the same "GPL with exceptions for other thorns"
license as the Cactus flesh; see the file CACTUS.COPYRIGHT in this
directory for details.
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The new code added in the June 2002 revisions to this thorn
is copyright (C) 2001-2002 by Jonathan Thornburg <jthorn@aei.mpg.de>
Minkowski_conf_wave and the conformal factor code added in January 2003
is copyright (C) 2003 by Frank Loeffler <frank.loeffler@aei.mpg.de>
Option to boost any non-stress-energy-tensor model
is copyright (C) 2003 by Jonathan Thornburg <jthorn@aei.mpg.de>
This code is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This code is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this thorn (see the file COPYING in this directory);
if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA
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