Pepito

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**[[Home]] * [[Engines]] * Pepito**

**Pepito**,
a [[Chess Engine Communication Protocol]] and [[UCI]] compliant [[Open Source Engines|open source chess engine]] written by [[Carlos del Cacho]] in [[C]], first released in September 2000 <ref>[[http://www.stmintz.com/ccc/index.php?id=129855|New winboard engine released!]] by [[Carlos del Cacho]], [[CCC]], September 18, 2000</ref> <ref>[[http://wbec-ridderkerk.nl/html/details1/Pepito.html|Pepito]] from [[WBEC|WBEC Ridderkerk]]</ref>. The recent version comes with an own [[GUI]] written in [[Cpp|C++]] using [[http://en.wikipedia.org/wiki/WxWidgets|wxWidgets]] and can create [[Opening Book|opening book databases]] from a pile of thousands of chess games, applying advanced data structures such as [[http://en.wikipedia.org/wiki/B-tree|B-trees]] and [[http://en.wikipedia.org/wiki/Skip_list|skip lists]] <ref>[[http://www.behance.net/gallery/Pepito-Chess-engine/870970|Pepito Chess engine on Behance]]</ref>. As [[Bitboards|bitboard]] engine, Pepito applies [[Rotated Bitboards|rotated bitboards]] with 1/2 MiB lookup tables, indexed by the full [[Occupancy of any Line|8-bit line occupancy]], to determine [[Sliding Piece Attacks|sliding piece attacks]]. Pepito played the [[CCT4]], [[CCT5]] and [[CCT6]] tournaments.

=Screenshot=
|| [[image:Pepito.jpg link="http://www.behance.net/gallery/Pepito-Chess-engine/870970"]] ||
|| Pepito [[GUI]] <ref>[[http://www.behance.net/gallery/Pepito-Chess-engine/870970|Pepito Chess engine on Behance]]</ref> ||

=Features=
* [[NegaScout]] search algorithm
* [[Extensions]] to avoid [[Horizon Effect|horizon effect]] (i.e. [[Check Extensions|check]], [[Recapture Extensions|recapture]], [[Passed Pawn Extensions|pawn push]], ...)
* [[Transposition Table|Transposition tables]], [[Pawn Hash Table|pawn hash tables]] and [[Evaluation Hash Table|evaluation cache]]
* [[AEL-Pruning|AEL-pruning]] à la [[Ernst A. Heinz|Heinz]]
* [[Static Exchange Evaluation|Static exchange evaluator]], used for [[Move Ordering|move ordering]] and also to cull losing [[Captures|captures]] in the [[Quiescence Search|quiescence search]]
* [[Lazy Evaluation|Lazy evaluation]]
* [[Nalimov Tablebases]]
* [[Pondering]]
* [[Book Learning|Book learning]]

=Acknowledgments=
Pepito wouldn't have come to life without the help from these guys, acknowledged by Carlos del Cacho in thanx.txt, shipped with the source files <ref>[[http://kirr.homeunix.org/chess/engines/Norbert%27s%20collection/Pepito%20%28Compilation%29/v1.59/Windows/thanx.txt|thanx.txt]]</ref>:
* [[Robert Hyatt|Bob Hyatt]] ([[Crafty]])
* [[Dušan Dobeš]] ([[Phalanx]])
* [[Dan Homan]] ([[EXchess]])
* [[Adrien Regimbald]] ([[Faile]])
* [[Jon Dart]] ([[Arasan]])
* [[Andrew Tridgell]] & [[Jonathan Baxter]] ([[KnightCap]])
* [[Stuart Cracraft]] & [[Chua Kong Sian]] ([[GNU Chess|GNU Chess 5]])
* [[John Stanback]] ([[GNU Chess|GNU Chess 4]])

... further ...
* [[Eugene Nalimov]] for his [[Endgame Tablebases]]

... and 
* [[Jonathan Schaeffer]]
* [[Alexander Reinefeld]]
* [[Ernst A. Heinz]]
* [[Aske Plaat]]

for their papers, and 
* [[Bruce Moreland]]
* [[Dieter Bürssner]]
* [[Brian Richardson]]
* [[Tony van Roon-Werten|Tony Werten]] 

and many others at [[CCC]] for their help...

=Selected Games=
[[CCT4]], round 2, [[Pepito]] - [[Yace]] <ref>[[http://www.vrichey.de/cct4/|CCT4 - PGN-Download]] hosted by [[Volker Richey]]</ref>
[[code]]
[Event "CCT4"]
[Site "Internet Chess Club"]
[Date "2002.01.19"]
[Round "2"]
[White "Pepito"]
[Black "Yace"]
[Result "1/2-1/2"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Be3 e6 7.f3 b5 8.g4 h6 
9.Qd2 Nbd7 10.O-O-O Bb7 11.h4 b4 12.Na4 Qa5 13.b3 Nc5 14.a3 Rc8 15.Qxb4 
Qc7 16.Nxc5 dxc5 17.Qa4+ Nd7 18.Ne2 c4 19.b4 Bc6 20.Qxa6 Ra8 21.Qxc4 Rxa3 
22.Bf4 Qb7 23.c3 Bb5 24.Qd4 Ra2 25.Kb1 Rxe2 26.Rh3 e5 27.Bxe5 Bc5 28.Qd5 
Bc6 29.Qc4 Bb5 30.Qd5 Bc6 31.Qc4 Bb5 32.Qd5 1/2-1/2
[[code]]

=Clones=
The program [[Siboney]] by [[Francisco Rivera]] published in 2002 was based on Pepito with a changed [[Evaluation|evaluation]] <ref>[[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=37440&p=142378|Siboney is at the moment not available!]] by [[Frank Quisinsky]], [[Computer Chess Forums|Winboard Forum]], May 24, 2002</ref> <ref>[[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=37909&p=144333|What is the state of Siboney now?]] by [[Günther Simon]], [[Computer Chess Forums|Winboard Forum]], June 26, 2002</ref> <ref>[[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=38504&p=146960|Siboney = a Pepito clone ??]] by [[Brice Boissel]], [[Computer Chess Forums|Winboard Forum]], August 06, 2002</ref>. In 2003, [[Deep<9>]] by pretended author [[Denis Grafen]] was proven a blatant [[Clones|clone]] of Pepito <ref>[[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=41578&p=158612|Re: A Deep question]] by [[Carlos del Cacho]], [[Computer Chess Forums|Winboard Forum]], March 05, 2003</ref> <ref>[[http://www.stmintz.com/ccc/index.php?id=289305|The truth about Deep <9>]] by [[Thomas Mayer]], [[CCC]], March 14, 2003</ref> <ref>[[http://www.stmintz.com/ccc/index.php?id=289424|Information]] by [[Denis Grafen]], [[CCC]], March 15, 2003</ref>.

=See also=
* [[Various Classifications#Comics|Comics]]
* [[Various Classifications#GivenName|Given Name]]

=Forum Posts=
==2000==
* [[http://www.stmintz.com/ccc/index.php?id=129855|New winboard engine released!]] by [[Carlos del Cacho]], [[CCC]], September 18, 2000
* [[http://www.stmintz.com/ccc/index.php?id=130012|Pepito 1.01 uploaded! Bugfix + adjustable hash size]] by [[Carlos del Cacho]], [[CCC]], September 20, 2000
* [[http://www.stmintz.com/ccc/index.php?id=130421|About Pepito and Amyan]] by [[José Carlos Martínez Galán|José Carlos]], [[CCC]], September 24, 2000 » [[Amyan]]
* [[http://www.stmintz.com/ccc/index.php?id=130515|Pepito 1.03 available (Move now support & José C. bug fixed)]] by [[Carlos del Cacho]], [[CCC]], September 25, 2000
* [[http://www.stmintz.com/ccc/index.php?id=146024|Pepito v1.10 available w source]] by [[Carlos del Cacho]], [[CCC]], December 22, 2000
==2001==
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=34671&p=131024|Pepito 1.40 MMX LCT2 test]] by [[Gabor Szots]], [[Computer Chess Forums|Winboard Forum]], October 02, 2001 » [[LCT II]]
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=34689&p=131081|Pepito 1.42 MMX build]] by [[Dann Corbit]], [[Computer Chess Forums|Winboard Forum]], October 04, 2001
==2002==
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=37894&p=144268|The New Pepito...]] by [[Dann Corbit]], [[Computer Chess Forums|Winboard Forum]], June 24, 2002
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=38337&p=146188|new Pepito version available for download]] by [[Carlos del Cacho]], [[Computer Chess Forums|Winboard Forum]], July 27, 2002
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=38372&p=146353|Config.dat for Pepito]] by [[Carlos Pesce]], [[Computer Chess Forums|Winboard Forum]], July 30, 2002
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=38378&p=146377|New format of Config.dat for Pepito (built from the readme!)]] by [[Günther Simon]], [[Computer Chess Forums|Winboard Forum]], July 30, 2002
* [[http://www.stmintz.com/ccc/index.php?id=243447|Pepito 1.55 ( Read for fixes)]] by Nolan Denson, [[CCC]], July 31, 2002
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=38504&p=146960|Siboney = a Pepito clone ??]] by [[Brice Boissel]], [[Computer Chess Forums|Winboard Forum]], August 06, 2002 <ref>[[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=37909&p=144333|What is the state of Siboney now?]] by [[Günther Simon]], [[Computer Chess Forums|Winboard Forum]], June 26, 2002</ref>
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=39894&p=152458|Pepito 1.54 and learning]] by [[Igor Korshunov]], [[Computer Chess Forums|Winboard Forum]], November 12, 2002
==2003==
* [[http://www.stmintz.com/ccc/index.php?id=289182|Deep<9> Is a Clone based of Pepito? Really?]] by [[Volker Richey]], [[CCC]], March 13, 2003
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=41725&p=159242|Deep9, Pepito and Leo's Qualify]] by [[Matthias Gemuh]], [[Computer Chess Forums|Winboard Forum]], March 13, 2003
==2004 ...==
* [[http://www.stmintz.com/ccc/index.php?id=346386|Pepito @ CCT6 After thoughts]] by Nolan Denson, [[CCC]], February 01, 2004
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=46805&p=177043|Pepito problem]] by [[Tord Romstad]], [[Computer Chess Forums|Winboard Forum]], March 10, 2004
* [[http://www.talkchess.com/forum/viewtopic.php?t=18466&|Pepito 1.59 Windows 64-bit build available]] by [[Jim Ablett]], [[CCC]], December 20, 2007

=External Links=
==Chess Engine==
* [[http://www.behance.net/gallery/Pepito-Chess-engine/870970|Pepito Chess engine on Behance]]
* [[http://www.quarkchess.de/pepito/|Pepito... that other xboard chess engine]] hosted by [[Thomas Mayer]]
* [[http://wbec-ridderkerk.nl/html/details1/Pepito.html|Pepito]] from [[WBEC|WBEC Ridderkerk]]
* [[http://kirr.homeunix.org/chess/engines/Norbert%27s%20collection/Pepito%20%28Compilation%29/|Index of /chess/engines/Norbert's collection/Pepito (Compilation)]] by [[Norbert Raimund Leisner]], hosted by [[Kirill Kryukov]]
* [[http://www.computerchess.org.uk/ccrl/404/cgi/engine_details.cgi?print=Details+%28text%29&eng=Pepito%201.59.2%2064-bit|Pepito 1.59.2 64-bit]] in [[CCRL|CCRL 40/4]]
* [[http://computerchess.org.uk/ccrl/4040/cgi/engine_details.cgi?print=Details+%28text%29&eng=Pepito%201.59%2032-bit|Pepito 1.59 32-bit]] in [[CCRL|CCRL 40/40]]
* [[http://computerchess.org.uk/ccrl/4040/cgi/engine_details.cgi?match_length=30&print=Details&each_game=1&eng=Pepito%201.59%2064-bit|Pepito 1.59 64-bit]] in [[CCRL|CCRL 40/40]]
==Misc==
* [[http://en.wikipedia.org/wiki/Pepito|Pepito (disambiguation) from Wikipedia]]
* [[http://en.wikipedia.org/wiki/Pepe|Pepe (disambiguation) from Wikipedia]]
* [[http://en.wikipedia.org/wiki/Pepito_%28comics%29|Pepito (comics) from Wikipedia]]

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