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NNUE layers in action <ref>Image courtesy Roman Zhukov, revised version of the image posted in [http://talkchess.com/forum3/viewtopic.php?f=2&t=74059&start=139 Re: Stockfish NN release (NNUE)] by Roman Zhukov, [[CCC]], June 17, 2020</ref>
[[Hisayori Noda|Nodchip]] explained on [[https://en.wikipedia.org/wiki/Discord_(software) Discord]] on June 2020<ref>[http://talkchess.com/forum3/viewtopic.php?f=7&t=74780 Don't understand NNUE ] by [[Lucasart]], [[CCC]], August 14, 2020</ref>:
41,024 = 64 * 641. 64 comes from the number of the cells where king may exist. 641 = 64 * 5 * 2 + 1. 64 here comes from the number of the cells where a piece other than king may exist. 5 is the number of piece types other than king. 2 is the number of the colors, white and black. 1 is a captured piece.
"+ 1" is BONA_PIECE_ZERO.
Here "bona" means "[[Bonanza|bonanza]]" which is a popular computer [[Shogi|shogi ]] engine. It introduced the feature "p" for the first time.
BonaPieces are contained in the evalList. It is updated by Position::do_move() and Position::undo_move(), and used by NNUE to calculate the network parameters between the input layer and the first hidden layer.
About the calculation, the following text will be helpful. This text is sent to RocketMiningPoo on Twitter.
=Hybrid=
In August 2020 a new patch changed Stockfish NNUE into a hybrid engine: it uses NNUE evaluation only on quite balanced material positions, otherwise uses the classical one <ref>[https://github.com/official-stockfish/Stockfish/pull/2916 NNUE evaluation threshold, [[by MJZ1977 · Pull Request #2916 · official-stockfish/Stockfish · GitHub]], August 06, 2020</ref>.
=Strong Points=
* [http://talkchess.com/forum3/viewtopic.php?t=74739 SF NNUE training questions] by [[Jouni Uski]], [[CCC]], August 10, 2020
* [http://www.talkchess.com/forum3/viewtopic.php?f=7&t=74777 Neural Networks weights type] by [[Fabio Gobbato]], [[CCC]], August 13, 2020
* [http://talkchess.com/forum3/viewtopic.php?f=7&t=74780 Don't understand NNUE] by [[Lucasart]], [[CCC]], August 14, 2020
=External Links=
