Fabien+Letouzey

a French computer chess and games programmer and developer of the strong chess programs Fruit, Chess-64 and Senpai, the Othello programs //Turtle//, //Snail// , //Piloth// , //Decapus// (10x10) and //Octopus// (8x8), the latter Gold medal winners at the 20th Computer Olympiad, Leiden 2017, the UCI-Winboard adapter Polyglot, and the International Draughts programs //Toy// , and Scan, which surprised the Draughts scene in winning the 18th Computer Olympiad, Leiden 2015, and defended its title in 2016 and 2017 respectively. Fabien further works with Rémi Coulom to improve his Go playing program Crazy Stone due to deep learning. || toc =Fruit= The release of Fruit until version 2.1 under GNU General Public License was a "revolution" in computer chess in 2005 - an open source program was "suddenly" competitive with the long time leading programs Shredder and Junior, as demonstrated at the WCCC 2005, where Fruit became runner up behind Zappa. After the great success of Reykjavik, and Fabien Letouzey met his professional colleagues, he decided to close the source and to go commercial - short after Fruit derivate appeared, based on the source code of Fruit 2.1, most notably Toga by Thomas Gaksch. Fabien finished his commercial computer chess career so far in 2007. Fruit 2.3+ is non GPL with full rights given to Ryan Benitez, while Fruit 2.1 is now owned by the Free Software Foundation.
 * Home * People * Fabien Letouzey**
 * [[image:FabienLetouzey2005.JPG]] ||~  || **Fabien Letouzey**,
 * Fabien Letouzey ||~  ||^   ||

=Anniversary= In March 2014, ten years after the initial Fruit 1.0 release, Fabien announced and published his new open source engine Senpai, and an independent fork of Fruit 2.1, Fruit Reloaded by Fabien Letouzey, Daniel Mehrmann and Ryan Benitez , both hosted by Steve Maughan's Computer Chess Programming.

=Photos=

Shredder - Fruit
code [Event "WCCC 2005"] [Site "Reykjavík, Iceland"] [Date "2005.08.16"] [Round "5"] [White "Shredder"] [Black "Fruit"] [Result "0-1"]
 * [[image:ShredderFruit2005.jpg width="560"]] ||
 * WCCC 2005: Stefan Meyer-Kahlen and Fabien Letouzey, Shredder - Fruit ||

1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxd4 Nc6 5.Nc3 a6 6.Be2 d6 7.Be3 Nf6 8.f4 Be7 9.O-O Qc7 10.Qe1 O-O 11.Kh1 Nxd4 12.Bxd4 b5 13.Qg3 Bb7 14.a3 Bc6 15.Bd3 Rfd8 16.Rae1 Qb7 17.Bxf6 Bxf6 18.e5 Be7 19.Ne4 dxe5 20.fxe5 Rd5 21.Re2 Rf8 22.Nf6+ Bxf6 23.Rxf6 Rd4 24.Rh6 g6 25.Rh4 Rxh4 26.Qxh4 Qb6 27.Qf4 Rd8 28.Rf2 Rd7 29.c3 Qc7 30.Qe3 Qd8 31.Bf1 Rd1 32.Kg1 Qd5 33.Re2 a5 34.Qf2 b4 35.axb4 axb4 36.cxb4 h6 37.Re1 Rxe1 38.Qxe1 Qd4+ 39.Qf2 Qxb4 40.h3 Be4 41.Kh2 Bd5 42.Bd3 Qb7 43.Qf6 Qb6 44.Qh4 Qb8 45.Qf6 Qb7 46.Bb1 Qd7 47.Qh4 Qc7 48.Qf4 Ba8 49.b4 Qb7 50.Qd2 Kg7 51.Qb2 Qb5 52.Kg1 h5 53.Ba2 Qd3 54.Qf2 Kg8 55.Kh2 Be4 56.Qb2 h4 57.b5 g5 58.Qf2 Qc3 59.b6 Kf8 60.Kg1 Qa1+ 61.Kh2 Qxe5+ 62.Kg1 Qa1+ 63.Kh2 Qc3 64.Kg1 Ke7 65.Kh2 f5 66.Kg1 Kd7 67.Kh2 Kc6 68.Qe2 Kxb6 69.Qf2+ Kc6 70.Qe2 Kd6 71.Bc4 Qe5+ 72.Kg1 Qd4+ 73.Kh2 g4 74.hxg4 fxg4 75.Qxg4 Qxc4 76.Qxh4 Qe2 77.Qd8+ Kc6 78.Qc8+ Kb5 79.Qb8+ Kc4 80.Qc7+ Kd3 81.Qd6+ Bd5 82.Qa6+ Kd2 83.Qa5+ Kc2 84.Qa4+ Bb3 85.Qd4 e5 86.Qa7 e4 87.Qc5+ Bc4 88.Qa3 Qd3 89.Qa5 e3 90.Qa4+ Qb3 91.Qe8 e2 92.Qe4+ Kb2 93.Qh4 Qc3 94.Qf2 0-1 code

Winners

 * [[image:Winners2005.jpg width="560"]] ||
 * Winners 2005, Stefan Meyer-Kahlen, Fabien Letouzey, Anthony Cozzie and Gian-Carlo Pascutto ||

Olympiad Impression

 * [[image:FabienLetouzeyScan10x10Draughts2015.JPG]] ||
 * 10 years later, Fabien's program Scan wins 10x10 Draughts at the 18th Computer Olympiad ||

Winners

 * [[image:Draghts10x10Prizes2015.jpg link="https://icga.leidenuniv.nl/?page_id=1497"]] ||
 * Winners: Bert Tuyt (2nd), Fabien Letouzey, Ron Van Bemmelen and TD Jaap Bus ||

=Selected Publications=
 * [|Francesco de Comité], [|François Denis], [|Rémi Gilleron], Fabien Letouzey (**1999**). //Positive and Unlabeled Examples help Learning//, The 10th International Conference on Algorithmic Learning Theory, available as [|ps]
 * Fabien Letouzey, [|François Denis], [|Rémi Gilleron] (**2000**). //Learning from Positive and Unlabeled Examples//. ALT 2000: 71-85, available as [|ps]
 * [|François Denis], [|Rémi Gilleron], Fabien Letouzey (**2005**). //Learning from positive and unlabeled examples//. Theor. Comput. Sci. 348(1): 70-83

=Forum Posts=

2000 ...

 * [|calculating the PV using MTD] by Fabien Letouzey, CCC, September 11, 2002 »  MTD(f), Principal variation
 * [|Re: Fruit - Question for Fabien] by Fabien Letouzey, CCC, March 11, 2004 » Node Types, Transposition Table, Principal Variation Search
 * [|Fruit, trying to answer various missed posts] by Fabien Letouzey, CCC, March 15, 2004
 * [|Fruit 1.0 UCI (with source code) now available] by Fabien Letouzey, CCC, March 17, 2004

2005 ...

 * [|Safe I/O (repeated)] by Fabien Letouzey, Winboard Forum, February 11, 2005
 * [|To Fruit's author Fabien Letouzey and commercial manager Joachim Rang] by Marc Lacrosse, CCC, November 17, 2005

2010 ...

 * [|Fabien's open letter to the community] by Tord Romstad, CCC, January 23, 2011 » Fabien Rybka Letter
 * [|Fabien's open letter to the community] by Tord Romstad, OpenChess Forum, January 23, 2011
 * [|Interview with Fabien (from the year 2005) ...] by Frank Quisinsky, CCC, January 25, 2011
 * [|What is a derivative?] by Fabien Letouzey, CCC, January 27, 2011 » Clones
 * [|GPL / GNU Licence enforcement] by Fabien Letouzey, CCC, January 27, 2011 » Free Software Foundation
 * [|Programming language features for computer chess] by Fabien Letouzey, CCC, January 27, 2011
 * [|Senpai 1.0 (new engine)] by Fabien Letouzey, CCC, March 17, 2014
 * [|Fruit 1.0 anniversary] by Fabien Letouzey, CCC, March 17, 2014

2015 ...

 * [|Re: Draughts at the ICGA Olympiad] by Fabien Letouzey, CCC, April 30, 2015
 * [|A little more info about Scan by Fabien Letouzey] by Jesús Muñoz, CCC, July 06, 2015
 * [|Scan] by Fabien Letouzey, [|World Draughts Forum], July 08, 2015

=External Links=
 * [|Fabien Letouzey's ICGA Tournaments]
 * [|The alternative to Crafty, Interview with Fabien Letouzey] by Frank Quisinsky, Arena Chess GUI 3.0 - Archive, Page 7, 96, April 05, 2005, [|also hosted] by Ed Schröder
 * [|Fabien Letouzey - The Othello Wiki Book Project]
 * [|Senpai Chess Engine - Computer Chess Programming] hosted by Steve Maughan
 * [|Fruit Reloaded - Computer Chess Programming] hosted by Steve Maughan

=References= =What links here?= include page="Fabien Letouzey" component="backlinks" limit="120"
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