Gullydeckel

**[[Home]] * [[Engines]] * Gullydeckel**
|| [[image:Rome-SPQR.JPG link="https://commons.wikimedia.org/wiki/File:Rome-SPQR.JPG"]] ||~   || **Gullydeckel**,
a free [[Open Source Engines|open source engine]] under the [[Free Software Foundation#GPL|GNU General Public License]] written in [[C]] by [[Martin Borriss]]. Supported platforms are [[Linux]] and [[Windows]]. Gullydeckel is [[Chess Engine Communication Protocol]] compliant.

Gullydeckel's [[Board Representation|board representation]] relies on [[Piece-Lists]] and [[0x88]]. Its [[Search|search]] is plain [[Alpha-Beta|alpha-beta]] using a recursive [[Null Move Pruning|null move pruning]] with [[Depth Reduction R|depth reduction R]] of 2.  ||
|| [[https://en.wikipedia.org/wiki/Manhole_cover|Manhole cover]] in [[https://en.wikipedia.org/wiki/Rome|Rome]] <ref>[[https://en.wikipedia.org/wiki/Manhole_cover|Manhole cover]] in [[https://en.wikipedia.org/wiki/Rome|Rome]] with [[https://en.wikipedia.org/wiki/SPQR|SPQR]] inscription, Image by [[https://en.wikipedia.org/wiki/User:Indian_Joe|Indian Joe]], January 08, 2007, [[https://en.wikipedia.org/wiki/Wikimedia_Commons|Wikimedia Commons]], [[https://en.wikipedia.org/wiki/SPQR|SPQR from Wikipedia]]</ref> ||~   ||^   ||
[[toc]]
=0x88 Difference=
The preinitialized <span style="background-color: #e5e4e4;">{{static int vector[256]}}</span> in "attacks.c" <ref>[[http://borriss.com/|Gullydeckel Chess Program - Download]]</ref> with [[Direction#RayDirections|ray directions]] encoded, which is indexed by [[0x88#SquareRelations|0x88 square difference]] plus offset, somehow reminds on a [[http://de.wikipedia.org/wiki/Schachtdeckel|Gullydeckel]], the colloquial German name for [[https://en.wikipedia.org/wiki/Manhole_cover|Manhole cover]] <ref>edited, symbols replaced for column alignment</ref>:
[[code format="cpp"]]
/*
if we find that two squares are related according to matrix SqRel,
we use another matrix to look up the direction of the move required
('to walk the vector') if it is a sliding piece (R,B,Q)
*/

static int vector[256] = {
   0  ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,UR,0 ,0 ,0 ,0 ,0 ,0 ,
   UP ,0 ,0 ,0 ,0 ,0 ,0 ,UL,0 ,0 ,UR,0 ,0 ,0 ,0 ,0 ,
   UP ,0 ,0 ,0 ,0 ,0 ,UL,0 ,0 ,0 ,0 ,UR,0 ,0 ,0 ,0 ,
   UP ,0 ,0 ,0 ,0 ,UL,0 ,0 ,0 ,0 ,0 ,0 ,UR,0 ,0 ,0 ,
   UP ,0 ,0 ,0 ,UL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,UR,0 ,0 ,
   UP ,0 ,0 ,UL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,UR,0 ,
   UP ,0 ,UL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,UR,
   UP ,UL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,RI,RI,RI,RI,RI,RI,RI,
   0  ,LE,LE,LE,LE,LE,LE,LE,0 ,0 ,0 ,0 ,0 ,0 ,0 ,DR,
   DN ,DL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,DR,0 ,
   DN ,0 ,DL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,DR,0 ,0 ,
   DN ,0 ,0 ,DL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,DR,0 ,0 ,0 ,
   DN ,0 ,0 ,0 ,DL,0 ,0 ,0 ,0 ,0 ,0 ,DR,0 ,0 ,0 ,0 ,
   DN ,0 ,0 ,0 ,0 ,DL,0 ,0 ,0 ,0 ,DR,0 ,0 ,0 ,0 ,0 ,
   DN ,0 ,0 ,0 ,0 ,0 ,DL,0 ,0 ,DR,0 ,0 ,0 ,0 ,0 ,0 ,
   DN ,0 ,0 ,0 ,0 ,0 ,0 ,DL,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0
 };
[[code]]
=Forum Posts= 
* [[http://groups.google.com/group/rec.games.chess.computer/msg/0269247c3d2a197f|Re: Deep Quiesence Searching]] by [[Martin Borriss]], [[Computer Chess Forums|rgcc]], February 26, 1997
* [[http://www.stmintz.com/ccc/index.php?id=145760|Gullydeckel - move generator]] by [[Thomas Mayer]], [[CCC]], December 20, 2000

=External Links= 
* [[http://borriss.com/|Gullydeckel Chess Program]]
* [[https://en.wikipedia.org/wiki/Manhole_cover|Manhole cover from Wikipedia]]
* [[https://en.wikipedia.org/wiki/Storm_drain|Storm drain from Wikipedia]]
* [[https://en.wikipedia.org/wiki/Sanitary_sewer|Sanitary sewer from Wikipedia]]
* [[https://en.wikipedia.org/wiki/Gully_%28disambiguation%29|Gully (disambiguation) from Wikipedia]]
* [[http://commons.wikimedia.org/wiki/Manhole_cover|Manhole cover - Wikimedia Commons]]
* [[http://www.flickr.com/groups/86393140@N00/|Flickr: Gullydeckel - Manhole Cover]]
* [[http://www.usatoday.com/news/nation/2008-06-29-Manhole_N.htm|New street crime: Thieves lift manhole covers]], [[https://en.wikipedia.org/wiki/USA_Today|USA Today]], June 29, 2008
* [[http://www.tagesspiegel.de/berlin/polizei-justiz/metalldiebe-stehlen-reihenweise-gullydeckel/994204.html|Deckel-Klau: Metalldiebe stehlen reihenweise Gullydeckel - Polizei & Justiz - Berlin]], [[https://en.wikipedia.org/wiki/Der_Tagesspiegel|Der Tagesspiegel]], July 23, 2007 (German)

=References= 
<references />
=What links here?= 
[[include page="Gullydeckel" component="backlinks" limit="40" ]]
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