Ethereal

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|| [[image:320px-Striking_Night_Sky.jpg link="https://commons.wikimedia.org/wiki/File:Striking_Night_Sky.jpg"]] ||~ || **Ethereal**,
an [[UCI]] compliant [[Open Source Engines|open source chess engine]] written by [[Andrew Grant]] in [[C]], licensed under the [[Free Software Foundation#GPL|GNU GPL]] and first officially released in June 2016 <ref>[[http://kirill-kryukov.com/chess/discussion-board/viewtopic.php?f=7&t=8645|Ethereal - Official Release]] by [[Andrew Grant]], [[Computer Chess Forums|CCRL Discussion Board]], June 25, 2016</ref>. Ethereal is greatly influenced from [[Crafty]], [[Stockfish]], [[TSCP]], [[MadChess]], and [[Fruit]] <ref>[[https://github.com/AndyGrant/Ethereal/blob/master/README.md|Ethereal/README.md at master · AndyGrant/Ethereal · GitHub]]</ref>. ||
|| Ethereal night sky <ref>A [[https://en.wikipedia.org/wiki/Eclipse#Umbra,_penumbra_and_antumbra|total eclipse]] of the [[https://en.wikipedia.org/wiki/Moon|Moon]] is an impressive spectacle. But it also provides another viewing opportunity: a dark, moonlight-free starry sky. At [[https://en.wikipedia.org/wiki/Cerro_Paranal|Cerro Paranal]] in the Chilean [[https://en.wikipedia.org/wiki/Atacama_Desert|Atacama Desert]], one of the most remote places in the world, the distance from sources of light pollution makes the night sky all the more remarkable during a total [[https://en.wikipedia.org/wiki/Lunar_eclipse|lunar eclipse]]. This [[https://en.wikipedia.org/wiki/Panoramic_photography|panoramic photo]], taken by [[https://en.wikipedia.org/wiki/European_Southern_Observatory|ESO]] Photo Ambassador  [[https://www.facebook.com/yuribeletskyphoto|Yuri Beletsky]], shows the view of the starry sky from the site of ESO’s [[https://en.wikipedia.org/wiki/Very_Large_Telescope|Very Large Telescope]] (VLT) at Cerro Paranal during the total lunar eclipse of December 21, 2010. The reddish disc of the Moon is seen on the right of the image, while the [[https://en.wikipedia.org/wiki/Milky_Way|Milky Way]] arches across the heavens in all its beauty. Another faint glow of light is also visible, surrounding the brilliant planet [[https://en.wikipedia.org/wiki/Venus|Venus]] in the bottom left corner of the picture. This phenomenon, known as [[https://en.wikipedia.org/wiki/Zodiacal_light|zodiacal light]], is produced by sunlight reflecting off dust in the plane of the planets. It is so faint that it’s normally obscured by moonlight or light pollution. [[http://www.eso.org/public/images/potw1119a/|Image]] by ESO, Yuri Beletsky, [[https://creativecommons.org/licenses/by/4.0/deed.en|CC BY 4.0]], [[https://en.wikipedia.org/wiki/Wikimedia_Commons|Wikimedia Commons]], [[https://en.wikipedia.org/wiki/Beauty|Beauty from Wikipedia]]</ref> ||~ ||^ ||
[[toc]]
=Features=
<ref>Features based on [[https://github.com/AndyGrant/Ethereal|GitHub - AndyGrant/Ethereal: Ethereal UCI Chess Engine]]</ref>
==[[Board Representation]]==
* [[Bitboards]]
* [[Magic Bitboards#Fancy|Fancy Magic Bitboards]]
* [[8x8 Board]]
==[[Search]]==
* [[Lazy SMP]] since 8.60 SMP <ref>Ethereal's 8.60 [[Lazy SMP]] inspired by [[Demolito]] by Lucas Braesch, see [[http://www.talkchess.com/forum/viewtopic.php?t=65968|Release of Ethereal 8.60 SMP]] by [[Andrew Grant]], [[CCC]], December 10, 2017</ref>
* [[Iterative Deepening]]
* [[Aspiration Windows]]
* [[Principal Variation Search|PVS]] [[Alpha-Beta]]
* [[Transposition Table]]
* [[Selectivity]]
** [[Check Extensions]]
** [[Delta Pruning]]
** [[Futility Pruning]]
** [[Late Move Reductions]]
** [[Null Move Pruning|Null Move Pruning]]
** [[Razoring]]
** [[Reverse Futility Pruning]] (Static Null Move Pruning)
* [[Move Ordering]]
** [[Internal Iterative Deepening]]
** [[MVV-LVA|MVV/LVA]]
** [[Killer Heuristic]]
** [[History Heuristic]]
** [[Piece-Square Tables]]
==[[Evaluation]]==
* [[Tapered Eval]]
* [[Material]]
* [[Piece-Square Tables]]
* [[Mobility]]
* [[Outposts]]
* [[Rook on open file|Rook on (Half) Open File]]
* [[Rook on Seventh|Rook on 7th Rank]]
* [[Castling|Castling Ability]]
* [[Pawn Hash Table]]
* [[Pawn Structure]]

=See also=
* [[Various Classifications#Astronomy|Astronomy]]

=Forum Posts=
==2016==
* [[http://www.talkchess.com/forum/viewtopic.php?t=60023&start=18|Re: How to speed up my engine]] by [[Günther Simon]], [[CCC]], May 03, 2016
> [[http://www.talkchess.com/forum/viewtopic.php?t=60023&start=19|Re: How to speed up my engine]] by [[Andrew Grant]], [[CCC]], May 03, 2016
* [[http://www.talkchess.com/forum/viewtopic.php?t=60161|Ethereal Bitboard 6.26 Chess Engine...a star is born!]] by AA Ross, [[CCC]], May 14, 2016
* [[http://www.talkchess.com/forum/viewtopic.php?t=60596|Ethereal - Official Release]] by [[Andrew Grant]], [[CCC]], June 25, 2016
* [[http://kirill-kryukov.com/chess/discussion-board/viewtopic.php?f=7&t=8645|Ethereal - Official Release]] by [[Andrew Grant]], [[Computer Chess Forums|CCRL Discussion Board]], June 25, 2016
* [[http://www.talkchess.com/forum/viewtopic.php?t=61335|Release of Ethereal7.78]] by [[Andrew Grant]], [[CCC]], September 04, 2016
==2017==
* [[http://www.talkchess.com/forum/viewtopic.php?t=64162|Official release of Ethereal8.16]] by [[Andrew Grant]], [[CCC]], June 03, 2017
* [[http://www.talkchess.com/forum/viewtopic.php?t=65165|Ethereal8.28 Release]] by [[Andrew Grant]], [[CCC]], September 13, 2017
* [[http://www.talkchess.com/forum/viewtopic.php?t=65685|Ethereal8.37 Release]] by [[Andrew Grant]], [[CCC]], November 10, 2017 
* [[http://www.talkchess.com/forum/viewtopic.php?t=65968|Release of Ethereal 8.60 SMP]] by [[Andrew Grant]], [[CCC]], December 10, 2017
* [[http://www.talkchess.com/forum/viewtopic.php?t=65989|Ethereal 8.61 -- Small bugfix to 8.60]] by [[Andrew Grant]], [[CCC]], December 12, 2017
* [[http://www.talkchess.com/forum/viewtopic.php?t=66099|Time Managment translating to SMP]] by [[Andrew Grant]], [[CCC]], December 23, 2017 » [[Parallel Search]], [[Time Management]]
==2018==
* [[http://www.talkchess.com/forum/viewtopic.php?t=66606|Official Release of Ethereal9.00]] by [[Andrew Grant]], [[CCC]], February 15, 2018
* [[http://www.talkchess.com/forum/viewtopic.php?t=66882|Official Release of Ethereal9.30]] by [[Andrew Grant]], [[CCC]], March 20, 2018

=External Links=
==Chess Engine==
* [[https://github.com/AndyGrant/Ethereal|GitHub - AndyGrant/Ethereal: Ethereal UCI Chess Engine]]
* [[http://www.computerchess.org.uk/ccrl/404/cgi/compare_engines.cgi?family=Ethereal&print=Rating+list&print=Results+table&print=LOS+table&print=Ponder+hit+table&print=Eval+difference+table&print=Comopp+gamenum+table&print=Overlap+table&print=Score+with+common+opponents|Ethereal]] in [[CCRL|CCRL 40/4]]
==Misc==
* [[https://en.wiktionary.org/wiki/ethereal|ethereal - Wiktionary]]
* [[https://en.wikipedia.org/wiki/Ethereal|Ethereal from Wikipedia]]
* [[https://en.wikipedia.org/wiki/Ether|Ether from Wikipedia]]
* [[https://en.wikipedia.org/wiki/Ethereal_wave|Ethereal wave from Wikipedia]]
* [[https://en.wikipedia.org/wiki/Subtle_cardinal|Ethereal cardinal from Wikipedia]]
* [[https://www.truth-is-beauty.com/blog/style-identities-the-ethereal|The Ethereal]] from [[https://www.truth-is-beauty.com/home.html|Truth is Beauty]], July 07, 2015
* [[Videos#JeanLucPonty|Jean luc Ponty]] - [[https://en.wikipedia.org/wiki/Cosmic_Messenger|Ethereal Mood]] (1978), [[https://en.wikipedia.org/wiki/YouTube|YouTube]] Video
> [[media type="youtube" key="JwibRL7Eqq4"]]

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