Gull

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Gull, (GullChess) an UCI compliant open source engine in the public domain by Vadim Demichev, inspired by ideas and code from other open source engines, notably from Ivanhoe of the Ippolit family of programs, and from Strelka, whose authors are suspected of reverse engineering Rybka, to examine and use her ideas. Ron Murawski's Computer-Chess Wiki mentions GullChess as Ivanhoe derivative. The further socialization of concrete implementations with disputed origin in the public domain, as already started with Ippolit, remains a highly controversial topic.

=Description= Gull applies magic bitboards to determine sliding piece attacks, a material table indexing scheme with disjoint light and dark bishops, PVS with aspiration windows, and a parallel search based on processes. Version 1.2 is written in compact and neat C++ code and consists of only one single source file. It features generic function templates in recursive search routines as well in various functions called by search, i.e. for move generation, with side to move and hash-move exclusion for singular extensions as boolean template parameters, delegating conditions on these to compile-time.

=Releases & Forks=

Gull 2.1
Gull 2.1, released in June 2013, has evaluation weights optimized with the use of automated tuning (source code included). Gull's 2.1 evaluation is no longer almost identical to that of Ivanhoe. Further, it features some minor search, time management and SMP efficiency enhancements.

Gull 2.8 beta
Gull 2.8 beta, released in January 2014 and competing TCEC Season 6, comes with minor search tweaks but a full evaluation rewrite, being back an original engine. A BMI2 build provides a small speedup on Haswell architecture due to the replacement of magic bitboards by PEXT bitboards.

Gull 3
Gull 3, released April 17, 2014, with further optimization of evaluation weights and a rewritten SMP search, features nonlinear king shelter evaluation and more endgame knowledge. Basil Falcinelli implemented a Linux port and Syzygy Bases support, introducing Fathom, while Michael Byrne worked on a Mac OS port dubbed Hawkeye , Tom Hyer introduced his Gull 3 derivative Roc , and Norman Schmidt SeaGull also based on Gull 3.

LazyGull
LazyGull is a free UCI chess engine under the MIT License derived from Gull 3 by Basil Falcinelli. LazyGull features Syzygy Bases support via Fathom, Lazy SMP, and PDEP bitboards for modern x86-64 CPUs, and is portable to Windows, Linux and MacOSX.

=See also=
 * Bird

=Forum Posts=

2010 ...

 * Проект "Чайка" by ThinkingALot, immortalchess, June 07, 2010, translated by Google Translate
 * GullChess by Olivier Deville, Winboard Forum, June 09, 2010
 * gull chess by Karger, OpenChess Forum, June 12, 2010
 * Re: gull chess by ThinkingALot, OpenChess Forum, June 13, 2010 » Gaviota
 * Re: gull chess by ThinkingALot, OpenChess Forum, June 17, 2013 (Gull 2.1)
 * Re: gull chess by ThinkingALot, OpenChess Forum, January 26, 2014 (Gull 2.8 beta & Gull 2.9 alpha)


 * GullChess 2.1 by Norbert Raimund Leisner, CCC, June 18, 2013
 * DTS-like SMP by ThinkingALot, OpenChess Forum, July 25, 2013 » Parallel Search
 * Re: Gull by ThinkingALot, immortalchess, February 10, 2014

2015 ...
2016 2017
 * Gull 3 (Linux port) released by Basil Falcinelli, CCC, October 28, 2015
 * Gull 3 x64 Mac Results by Michael B, CCC, October 30, 2015
 * Gull 3 Linux+Syzygy and Fathom released by Basil Falcinelli, CCC, November 20, 2015 » Fathom
 * Gull 3.0.1 available, takes advantage of hyperthreading by Dmitri Gusev, CCC, January 21, 2016
 * Gull 3.0 Syzygy in GitHub by Jose Mº Velasco, CCC, May 19, 2016
 * Gull 3 x64 by Michael B, CCC, July 01, 2016
 * Hawkeye 1.01 by Michael B, CCC, July 05, 2016
 * Hawkeye 1.01 Released by Michael B, CCC, July 07, 2016
 * Hawkeye is now on Github by Michael B, CCC, July 10, 2016
 * Hawkeye 1.02 Released by Michael B, CCC, July 11, 2016
 * HAwkeye 1.03 Released by Michael B, CCC, July 16, 2016
 * Future of Gull by Tom Hyer, CCC, August 23, 2016
 * New engine "Roc" by Tom Hyer, CCC, January 18, 2017
 * Open-source improvements released by Norman Schmidt, CCC, June 26, 2017
 * question: Gull 3 syzygy by kasinp, CCC, November 14, 201

=External Links=

Source Code Repositories

 * SourceForge.net: GullChess - Project Web Hosting - Open Source Software by ThinkingALot
 * GullChess | Free software downloads at SourceForge.net
 * hyer / SonsOfTheBird / source / Slizzard — Bitbucket by Tom Hyer
 * GitHub - Velmarin/Chess-Gull-Syzygy: Chess uci engine with support Syzygy tablebassses by Jose Mº Velasco
 * GitHub - MichaelB7/Hawkeye: UCI Chess Engine based on Gull by Michael Byrne
 * GitHub - TomHyer/Roc: C++ chess engine derived from Gull 3 by Tom Hyer
 * GitHub - basil00/Gull: Gull chess (Linux/Mac port) - The LazyGull Chess Engine by Basil Falcinelli
 * GitHub - FireFather/seagull: chess engine based on Gull 3 by Norman Schmidt

Rating

 * Gull 1.2 64-bit in CCRL 40/40
 * Gull 3 64-bit 4CPU in CCRL 40/40

Misc

 * Gull (Seagull) from Wikipedia
 * The Birds (story) from Wikipedia
 * The Birds (film) from Wikipedia
 * Frode Alnæs - Gull av hav, Kanestrøm 2016, YouTube Video

=References=

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