[tt] Wikipedia: Rybka

Fri Apr 18 20:31:18 UTC 2008

Rybka - Wikipedia, the free encyclopedia
http://en.wikipedia.org/w/index.php?title=Rybka&oldid=189874148&printable=yes

Rybka is a computer chess engine created by International Master
Vasik Rajlich. As of November 2007, Rybka is top-rated in all
notable chess engine rating lists^[1] and has won many official
Computer Chess Tournaments including the 2007 World Computer-Chess
Championship. Rybka supports both single processor and symmetric
multiprocessing (SMP) systems.

Contents

* 1 Name
* 2 Playing strength
* 3 Internals
* 4 Team
* 5 History
+ 5.1 Tournament participations
+ 5.2 Rybka versus grandmaster challenges
+ 5.3 Zappa match
* 6 Future release plans
* 7 References
* 8 External links

Name

The word rybka means little fish in the Czech language, where it is
pronounced [|rIpka]. Vasik Rajlich was once asked in an interview by
Alexander Schmidt, "Did you choose the name Rybka because your
program always slipped out of your hands like a little fish?" He
replied, "As for the name Rybka - I am sorry but this will remain my
private secret ."

Playing strength

Rybka 1.0 beta (which is available as a free download) has been
rated at 2809 Elo ^[2] (about the same strength as Toga II), and
Rybka 2.3.1 is estimated to be about 200 Elo stronger than 1.0 beta.
Newer versions of Rybka can also use multiple processors, yielding
an estimated increase of 50 Elo per doubling of processors. ^[3]

Rybka is significantly stronger - about 60% faster - when used in
64-bit mode than in 32-bit mode.^[3]

Internals

Rybka is a closed-source program, but still some details have been
revealed: Rybka uses a bitboard representation^[4], and is an
alpha-beta searcher with a relatively large aspiration window^[5].
It uses very aggressive pruning, leading to imbalanced search
trees^[6]. The details of the evaluation function are unknown, but
since version 2.3.1 it has included work by Larry Kaufman on
material imbalances, much of which was worked out in a series of
papers in the 90s.^[7]

Rybka has been accused of being based on Fruit, but Rajlich has
denied this categorically.^[8] Comments by the programmer reveal
Rybka does use some standard chess programming techniques, such as
the null-move heuristic and aspiration windows, along with other
null-window tricks.

Team

Iweta and Vasik Rajlich
Iweta and Vasik Rajlich

Vasik Rajlich is the main author of Rybka, with IM Larry Kaufman in
primary charge of the evaluation function since version 2.3. Iweta
Rajlich is the main Rybka tester. Jeroen Noomen (who used to work on
Rebel) is the author of its opening book.

History

^This short section requires expansion.

The first Rybka beta was released on December 2, 2005.

Tournament participations

In 2005, from December 27 to December 30, Rybka participated in the
15th International Computer Chess Championship in Paderborn,
Germany. Rybka won the tournament with a score of 5½ points out of
7, ahead of other engines such as Gandalf, Zappa, Spike, Shredder
and Fruit.

On the CCT8 from February 25 to February 26, Rybka won with a score
of 8 out of 9, going undefeated.

In the April 2006 PAL/CSS Freestyle main tournament, an unaided
Rybka 1.1 took first place. In the final tournament, Rybka 1.1
finished in second and third place, behind Hydra.

In the 6th Leiden ICT in May 2006, Rybka won with a score of 8½ out
of 9, ahead of Sjeng, Gandalf and Shredder.

At the 14th World Computer-Chess Championship in Turin, Italy in May
2006, Rybka, playing under the name Rajlich, finished second, tied
with Shredder, after Junior, the winning 2006 World champion.

In the June 2006 PAL/CSS Freestyle main tournament, the Rybka team,
playing under the handle Rajlich, tied for first place with
Intagrand. In the final, the Rybka team took clear first place, a
point ahead of the field. All 8 qualificants to the final were Rybka
users.

In the 2006 Dutch Open Computer Championships, Rybka 2.2 finished in
first place with a perfect score of 9 out of 9. ^[9]

In December 2006, Rybka participated in the 16th International
Computer Chess Championship in Paderborn, Germany. Rybka won the
tournament with a score of 6½ points out of 7. [1]

In February 2007 , Rybka participated in the CCT9 and Rybka won with
6/7. Rybka by Vasik Rajlich is CCT9 Champion

In the 7th Leiden ICT in May 2007, Rybka won with a score of 7½ out
of 9, ahead of Zappa and HIARCS. ^[10]

Rybka won the 15th World Computer Chess Championship in June 2007
with a score of 10 out of 11.

The Rybka team, playing under the handle Rajlich, won the June 2007
PAL/CSS Freestyle final with a score of 6/9.

Rybka versus grandmaster challenges

Whilst Rybka has won a match with GM Jaan Ehlvest which involved
giving a pawn odd to the human, IM Larry Kaufman of the Rybka team
has pledged his own money to a human GM that can beat Rybka in a
six-game match without material odds. GM Jaan Ehlvest was again
chosen to play Rybka, getting twice the thinking time and white
every match, with Rybka having only a three-move opening book,
limited (512MB) hash size, and no endgame tablebases (the match
being dubbed "Everything but a pawn"). The match ended 4.5-1.5 after
three Rybka wins and three draws.

Zappa match

In September 2007, Zappa defeated Rybka in a match, 5.5-4.5.

Future release plans

This article or section contains information about scheduled or
expected future software.
The content may change as the software release approaches and more
information becomes available.

The release date for Rybka 3.0 UCI is flexible, but the general
target is spring 2008. The following features have been confirmed,
though not all specifically for Rybka 3.0:
* In an interview with Frank Quisinsky, Vasik Rajlich revealed
plans for a future GUI that would "properly display chess
knowledge to the user.", most likely in the form of graphical
evaluation of the pieces on the board. The GUI is developed by
Convekta, and is currently in beta testing for a limited set of
users.
* Native Linux support has been confirmed without a specific date.
Rajlich' view on this is: "Generally, I'd like to say that we'll
support Linux from Rybka 3. However, schedules have a way of
slipping, so no promises yet."^[11] 32-bit Rybka does, however,
run under WINE, and 64-bit Rybka runs under both Linux and Mac
OS X using an experimental, Rybka-specific translation layer
called microwine.
* Chess960 support was implemented for the Chess Classic Mainz
2007, where Rybka subsequently won the computer Chess960
tournament.^[12]^[13]
* Support for Pocket PCs and similar mobile devices.^[14]
* And naturally, general playing strength improvements, including
increased multiprocessor improvements, increased search
efficiency, and better position evaluation.^[15]

Rajlich has asserted that Rybka will continue to use open protocols,
both for normal operations as well as for the data presented by the
Rybka 3 GUI.

References

1. http://computerchess.org.uk/ccrl/4040/index.html
Swedish Chess Computer Association Rating List
http://web.telia.com/~u85924109/ssdf/list.htm
Husvankempen
http://www.husvankempen.de/nunn/
Sedatchess
http://www.geocities.com/sedatchess/SCCT_Auto232.html
http://www.computerschach.de/cssrangliste/englisch/erangliste.htm

2. Rybka
http://www.superchessengine.com/rybka.htm
3. FAQ for Rybka 2.0-2.2n2
http://rybkachess.com/index.php?auswahl=FAQ+for+v+2.x
4. rybka source code
http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=20132#pid20132
5. Rybka search
http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=19588#pid19588
6. Rybka search
http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=17961#pid17961
7. Rybka @ Amsterdam 15th WCCC
http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=15090#pid15090
8. Is Rybka a derivative of Fruit?
http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=19118#pid19118
9. Rybkachess.com
http://www.rybkachess.com/docs/docc06.htm
10. International CSVN Tournament 2007
http://www.csvn.nl/index.php?option=com_content&task=view&id=258&Itemid=28
11. (Experimental) 64-bit Rybka on Linux
http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=18932#pid18932
12. Rybka in Chess Classic Mainz 2007, Chess 960
http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=14910#pid14910
13. CCM7 - 3. Livingston Chess960
Computer-Weltmeisterschaft. Chess Tigers. Retrieved on 2007-08-22.
http://chesstigers.de/ccm7/computer_wm.php?lang=0&kat=6&subkat=1
14. I want know if rybka will be developed for pocketpc
http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=18095#pid18095
15. No new Rybka version for the next six month?
http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=17722#pid17722

External links

* Official Site
http://www.rybkachess.com/
* Official Forum
http://www.rybkaforum.net/
* The 15th International Computer Chess Championship
http://wwwcs.uni-paderborn.de/~IPCCC/
* The CCRL Rating List
http://www.husvankempen.de/nunn/rating.htm
* The CEGT Rating List
http://www.computerchess.org.uk/ccrl/4040/
* Rybka's Games From ChessGames.com
http://www.chessgames.com/perl/chessplayer?pid=100439