Efficiently updatable neural network
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An efficiently updatable neural network (NNUE, a Japanese wordplay on Nue, sometimes stylised as ƎUИИ) is a neural network-based evaluation function whose inputs are piece-square tables, or variants thereof like the king-piece-square table.[1] NNUE is used primarily for the leaf nodes of the Alpha–beta tree.[2] While being slower than handcrafted evaluation functions, NNUE does not suffer from the 'blindness beyond the current move' problem.[3]
NNUE runs efficiently on central processing units without a requirement for a graphics processing unit (GPU). NNUE was invented by Yu Nasu and introduced to computer shogi in 2018.[4][5] On 6 August 2020, NNUE was for the first time ported to a chess engine, Stockfish 12.[6][7] As of 2021, all of the top rated classical chess engines have an NNUE implementation to remain competitive.
Compared to deep neural network based evaluations requiring a dedicated GPUs, NNUE avoids idle times during the substantial data transfer operations between GPU and CPU required before and after each evaluation.[citation needed]
The neural network used for shogi consists of four weight layers: W1 (16-bit integers) and W2, W3 and W4 (8-bit). Incremental computation and single instruction multiple data (SIMD) techniques are used with appropriate intrinsic instructions, specifically in the 2018 computer shogi implementation VPADDW, VPSUBW, VPMADDUBSW, VPACKSSDW, VPACKSSWB and VPMAXSB.[4]
See also
References
- ^ Gary Linscott (April 30, 2021). "NNUE". Retrieved December 12, 2020.
- ^ "Stockfish 12". Stockfish Blog. Retrieved 19 October 2020.
- ^ "Stockfish - Chessprogramming wiki". www.chessprogramming.org. Retrieved 2020-08-18.
- ^ a b Yu Nasu (April 28, 2018). "Efficiently Updatable Neural-Network-based Evaluation Function for computer Shogi" (PDF) (in Japanese).
- ^ Yu Nasu (April 28, 2018). "Efficiently Updatable Neural-Network-based Evaluation Function for computer Shogi (Unofficial English Translation)" (PDF).
- ^ "Introducing NNUE Evaluation". 6 August 2020.
- ^ Joost VandeVondele (July 25, 2020). "official-stockfish / Stockfish, NNUE merge".
External links
- NNUE on the Chess Programming Wiki.
- NNUE evaluation functions for computer shogi on github.com