422
edits
Changes
→2020 ...
'''Ethereal''',<br/>
an [[UCI]] compliant [[:Category:Open Source|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>.
On October 09, 2020, Andrew Grant initially announced his withdrawal from Ethereal's development with the releases of Ethereal '''V12.75'''
<ref>[http://www.talkchess.com/forum3/viewtopic.php?f=2&t=75335 Final Release of Ethereal, V12.75] by [[Andrew Grant]], [[CCC]], October 09, 2020</ref>
and Ethereal '''12.75 SF-NNUE''', the latter a [[NNUE]] implementation based on [[Stockfish NNUE]], to deliberately demonstrate how everybody may considerably improve the [[Playing Strength|playing strength]] of their engines without much effort
<ref>[http://www.talkchess.com/forum3/viewtopic.php?f=2&t=75335&start=91 Re: Final Release of Ethereal, V12.75] by [[Andrew Grant]], [[CCC]], October 09, 2020</ref>.
However, Andrew Grant voted for another direction, and announced a commercial release of Ethereal '''13.00''' (NNUE) ,
the free standard version still available on [https://en.wikipedia.org/wiki/GitHub Github] <ref name="Ethereal13NNUE">[http://www.talkchess.com/forum3/viewtopic.php?f=2&t=77438 Commercial Release of Ethereal 13.00 (NNUE) for AVX2 Systems] by [[Andrew Grant]], [[CCC]], June 04, 2021</ref>.
=Ethereal 13 (NNUE)=
'''Ethereal 13 (NNUE)''', the commercial Ethereal version for [[AVX2]] systems was released on June 04, 2021. The program comes with two [[NNUE|NNUEs]] for [[Evaluation|evaluation]],
one for standard chess, and the secondary network trained exclusively for [[Chess960]]. The NNUEs are not derived from, trained on, nor duplicated from the works of the [[Stockfish]] team <ref name="Ethereal13NNUE"/>. Andrew Grant on his NNUE approach <ref>[http://www.talkchess.com/forum3/viewtopic.php?f=2&t=77438&start=17 Re: Commercial Release of Ethereal 13.00 (NNUE) for AVX2 Systems] by [[Andrew Grant]], [[CCC]], June 04, 2021</ref>:
Ethereal is using the [[Stockfish NNUE#NNUE Structure|HalfKP]] paradigm, with a 40960x256 -> 512x32x32x1 Network. This is the textbook approach, but with some changes. Firstly, not all weights are quantized to int8 / int16 for the input layer. Instead, the network goes like this: int16_t => int16_t => (int32_t -> [[Float|float_t]]) => float_t => float_t. This approach allows us to never have to pack the data downwards, saving many operations, and also lets us take a slightly more expensive approach to the later layers in exchange for massively increased precision. If I eventually add support for [[AVX]] (not avx2) machines, it will be a significant gain as AVX does not have 256-bit vector support for integer types in a meaningful way.
During training the Network actually has 43850 input parameters, using a few factorization of the board to aid in training without having tens of billions of positions. In practice, each Net was trained somewhere between 2 and 4 billion positions total, evaluated by Ethereal / Ethereal NNUE. The networks are trained using a modified form of the [https://en.wikipedia.org/wiki/Stochastic_gradient_descent#Adam Adam] optimizer, which allows better performance for datasets with extremely sparse input fields. For example, with a Batch Size of 16384, only about 50% of the 43,850 parameters are used on average.
Data generation for a given network takes about 3 weeks, completed on a 104 core machine. From there, processing that data down into a list of [[Forsyth-Edwards Notation|FENs]] and then into the format used by Ethereal's NNTrainer takes another 12 hours or so. Finally, training the actual Network can take a few days, with many stops and starts to drop the learning rate and find a global optima.
The trainer itself is a fully original work, written in [[C]] and making use of all 104 threads. It includes some AVX2 and even AVX512 code for use in updating the network parameters. This toolkit was used in training the Halogen networks as well. It is fairly flexible and trying things like HalfKA, changing layer sizes, adding layers, changing activation functions, or adding more factorizers is only a few minutes of effort in the code. It rivals speeds of [[GPU]] based trainers, by leveraging massive SMP and efficient implementations.
=Features=
** [[Razoring]]
** [[Reverse Futility Pruning]] (Static Null Move Pruning)
** [[Static Exchange Evaluation|Static Exchange Evaluation Pruning]]
** [[Multi-Cut]] (12.00)
* [[Move Ordering]]
** [[Internal Iterative Deepening]]
** [[Killer Heuristic]]
** [[History Heuristic]]
** [[Piece-Square Tables]]
==[[Evaluation]]==
* [[NNUE]] (Ethereal 13.00 NNUE)
* [[Tapered Eval]]
* [[Material]]
* [[Pawn Hash Table]]
* [[Pawn Structure]]
* [[Automated Tuning]] by [[Automated Tuning#LogisticRegression|Logistic Regression]], [https://en.wikipedia.org/wiki/Stochastic_gradient_descent#AdaGrad AdaGrad] (12.50) <ref>[http://www.talkchess.com/forum3/viewtopic.php?f=7&t=74877 Evaluation & Tuning in Chess Engines] by [[Andrew Grant]], [[CCC]], August 24, 2020 </ref><ref>[http://www.talkchess.com/forum3/viewtopic.php?f=7&t=75350 Ethereal Tuning - Data Dump] by [[Andrew Grant]], [[CCC]], October 10, 2020</ref>
==Misc==
* [[Syzygy Bases]] using [[Syzygy Bases#Fathom|Fathom's]] probing code (9.65), superseded by 7-men [[Syzygy Bases#Pyrrhic|Pyrrhic]] (12.50)
=See alsoPublications=* [[Andrew Grant]] ('''2020'''). ''Evaluation & Tuning in Chess Engines''. <ref>[http:Category//www.talkchess.com/forum3/viewtopic.php?f=7&t=74877 Evaluation & Tuning in Chess Engines] by [[Andrew Grant]], [[CCC]], August 24, 2020 </ref> <ref>[http:Astronomy|Astronomy//www.talkchess.com/forum3/viewtopic.php?f=7&t=75350 Ethereal Tuning - Data Dump] by [[Andrew Grant]], [[CCC]], October 10, 2020</ref>
=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://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
* [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=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]]
* [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
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=67993&p=76840 Official Release of Ethereal 10.55] by [[Andrew Grant]], [[CCC]], July 16, 2018
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=68293 Ethereal 10.88 NUMA] by [[Norman Schmidt]], [[CCC]], August 24, 2018 » [[NUMA]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=69669 Official Release of Ethereal 11.25] by [[Andrew Grant]], [[CCC]], January 21, 2019
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=72215 For those that like to toy with Ethereal...] by [[Dann Corbit]], [[CCC]], October 30, 2019
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=72299 Official Release of Ethereal 11.75, supporting MultiPV] by [[Andrew Grant]], [[CCC]], November 11, 2019
==2020 ...==
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=73233 Official Release of Ethereal 12.00] by [[Andrew Grant]], [[CCC]], February 29, 2020
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=73629 Pawn structure tuning] by [[Vivien Clauzon]], [[CCC]], April 11, 2020 » [[Pawn Structure]], [[Automated Tuning]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=74809 Pyrrhic, Fathom for Humanoids] by [[Andrew Grant]], [[CCC]], August 16, 2020 » [[Syzygy Bases#Pyrrhic|Pyrrhic]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=74877 Evaluation & Tuning in Chess Engines] by [[Andrew Grant]], [[CCC]], August 24, 2020 » [[Automated Tuning]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=75047 Official Release of Ethereal 12.50] by [[Andrew Grant]], [[CCC]], September 08, 2020
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=75159 Ethereal Pawn-King NN] by [[Andrew Grant]], [[CCC]], September 19, 2020
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=75335 Final Release of Ethereal, V12.75] by [[Andrew Grant]], [[CCC]], October 09, 2020
: [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=75335&start=91 Re: Final Release of Ethereal, V12.75] by [[Andrew Grant]], [[CCC]], October 09, 2020
: [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=75335&start=134 Re: Final Release of Ethereal, V12.75] by [[Andrew Grant]], [[CCC]], November 12, 2020
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=75345 Request for someone to train an NNUE for Ethereal] by [[Andrew Grant]], [[CCC]], October 09, 2020 » [[NNUE]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=75350 Ethereal Tuning - Data Dump] by [[Andrew Grant]], [[CCC]], October 10, 2020
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=76049 Ethereal questions] by [[Gabor Szots]], [[CCC]], December 12, 2020
'''2021'''
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=77438 Commercial Release of Ethereal 13.00 (NNUE) for AVX2 Systems] by [[Andrew Grant]], [[CCC]], June 04, 2021
: [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=77438&start=17 Re: Commercial Release of Ethereal 13.00 (NNUE) for AVX2 Systems] by [[Andrew Grant]], [[CCC]], June 04, 2021
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=77503&start=55 Re: will Tcec allow Stockfish with a Leela net to play?] by [[Connor McMonigle]], [[CCC]], June 17, 2021 » [[NNUE]]
* [http://www.talkchess.com/forum3/viewtopic.php?f=2&t=77571 I declare that HCE is dead...] by [[Andrew Grant]], [[CCC]], June 29, 2021 » [[Evaluation|HCE]], [[NNUE]]
'''2022'''
* [https://www.talkchess.com/forum3/viewtopic.php?f=7&t=79160 Resolving once in a trillion crashes] by [[Andrew Grant]], [[CCC]], January 18, 2022 » [[Debugging]]
* [https://www.talkchess.com/forum3/viewtopic.php?f=2&t=79179 Commercial Release of Ethereal 13.50] by [[Andrew Grant]], [[CCC]], January 20, 2022
'''2023'''
* [https://talkchess.com/forum3/viewtopic.php?f=2&t=82750 Commercial Release of Ethereal 14.25] by [[Andrew Grant]], [[CCC]], October 21, 2023
=External Links=
==Chess Engine==
* [http://chess.grantnet.us/Ethereal/ Ethereal 13.00 (NNUE)]
* [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 Blitz]]* [http://www.computerchess.org.uk/ccrl/4040/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 40/15]]* [http://www.chessdom.com/ethereal-wins-tcec-division-4/ Ethereal wins TCEC Division 4], Interview with [[Andrew Grant]], [[Chessdom]], April 30, 2018 » [[TCEC Season 12]]* [httpshttp://www.dropboxchessdom.com/sethereal-chess-engine-leads-tcec-div-3-convincingly/nllk0w42wzun6u2Ethereal chess engine leads TCEC Div 3 convincingly], [[Chessdom]], August 12, 2018 » [[TCEC Season 13]]* [http:/Ethereal10/www.85chessdom.zip?dl=0 Dropbox] com/ethereal-chess-engine-wins-the-gold-at-tcec-div- 3/ Ethereal 10.85chess engine wins the gold at TCEC Div 3], [[Chessdom]], August 17, 2018
==Misc==
* [https://en.wiktionary.org/wiki/ethereal ethereal - Wiktionary]
* [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
* [[:Category:Jean-Luc Ponty|Jean-Luc Ponty]] - [https://en.wikipedia.org/wiki/Cosmic_Messenger Ethereal Mood] (1978), [https://en.wikipedia.org/wiki/YouTube YouTube] Video
: {{#evu:https://www.youtube.com/watch?v=JwibRL7Eqq4Va5_Y4QS3Eo|alignment=left|valignment=top}}
=References=
<references />
'''[[Engines|Up one Level]]'''
[[Category:Open Source]]
[[Category:GPL]]
[[Category:UCI]]
[[Category:PC]]
[[Category:X86]]
[[Category:X64]]
[[Category:Linux]]
[[Category:Windows]]
[[Category:Chess960]]
[[Category:OpenBench]]
[[Category:Commercial]]
[[Category:NNUE]]
[[Category:Jean-Luc Ponty]]
[[Category:Astronomy]]
