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/**************************************************************
*                                                             *
* scabble - interactive 3d scl ball explorer                  *
*                                                             *
*   Copyright Danny Calegari and                              *
*    Alden Walker 2010                                        *
*                                                             *
*  Uses code from exlp by Masashi Kiyomi                      *
*  and calls glpk and gmp by the GNU project                  *
*                                                             *
*  Released under the GPL license                             *
*                                                             *
**************************************************************/
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Current version: 1.0 -- February 3, 2011

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Theory:
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See Chapter 4 of:

Danny Calegari, scl, MSJ Memoirs 20. Mathematical Society of Japan, Tokyo, 2009


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Installation:
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Just type "make".  You will need gmp, gtk, gtkglext, and opengl.  If you're using
linux or fink, you can probably just install the packages for these things
using the default settings, and everything should work.

------
Usage:
------
Try the following:
Note there are some chains provided by default
 - press "run"
 - after a few seconds, press "pause"
 - press "step" a bunch of times
 - enter something like "0.2" in the tolerance box
 - press "run" and wait for it to finish
 - delete the tolerance and press "run" again


-------
License:
-------

scabble3d 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 3 of the License, or (at your
option) any later version.

scabble3d 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 scallop.  If not, see http://www.gnu.org/licenses/.

Because scabble uses the same strategy to compute scl as scallop, the same 
comments on rigor are appropriate (and the same fix applicable):

------
Rigour:
------

The algorithm that scallop uses to compute scl is rigorous
for (finite linear combinations of) (cyclically) *alternating words*:
those where a generator never appears twice (or more) in a row. 
Hence: abAB is alternating, aaab is not, a is not.

For nonalternating input, scallop rigorously computes upper
bounds on scl. Moreover, the output is "statistically" correct
on *most* input, especially if the value of scl is small.