An efficiently updatable neural network (NNUE, a Japanese wordplay on

Nue The Nue (鵺, 鵼, 恠鳥, or 奴延鳥) is a legendary yōkai or mononoke. Appearance In the ''Tale of Heike'', it is described as a Japanese chimera having the head of a monkey, the limbs of a tiger, the body of a Japanese raccoon dog and th ...

, sometimes stylised as ƎUИИ) is a

neural network A neural network is a network or circuit of biological neurons, or, in a modern sense, an artificial neural network, composed of artificial neurons or nodes. Thus, a neural network is either a biological neural network, made up of biological ...

-based

evaluation function An evaluation function, also known as a heuristic evaluation function or static evaluation function, is a function used by game-playing computer programs to estimate the value or goodness of a position (usually at a leaf or terminal node) in a g ...

whose inputs are

piece-square table An evaluation function, also known as a heuristic evaluation function or static evaluation function, is a function used by game-playing computer programs to estimate the value or goodness of a position (usually at a leaf or terminal node) in a g ...

s, or variants thereof like the king-piece-square table. NNUE is used primarily for the leaf nodes of the alpha–beta tree. While being slower than handcrafted evaluation functions, NNUE does not suffer from the 'blindness beyond the current move' problem. NNUE was invented by Yu Nasu and introduced to computer shogi in 2018. On 6 August 2020, NNUE was for the first time ported to a chess engine,

Stockfish Stockfish is unsalted fish, especially cod, dried by cold air and wind on wooden racks (which are called "hjell" in Norway) on the foreshore. The drying of food is the world's oldest known preservation method, and dried fish has a storage lif ...

12. Since 2021, all of the top rated classical chess engines such as

Komodo Dragon The Komodo dragon (''Varanus komodoensis''), also known as the Komodo monitor, is a member of the monitor lizard family Varanidae that is endemic to the Indonesian islands of Komodo, Rinca, Flores, and Gili Motang. It is the largest extant ...

have an NNUE implementation to remain competitive. NNUE runs efficiently on

central processing unit A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, an ...

s without a requirement for a

graphics processing unit A graphics processing unit (GPU) is a specialized electronic circuit designed to manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display device. GPUs are used in embedded systems, mobi ...

(GPU). The neural network used for the original 2018 computer shogi implementation consists of four weight layers: W1 (16-bit integers) and W2, W3 and W4 (8-bit). W1 encoded the king's position and therefore this layer needed only to be re-evaluated once the king moved. It used

incremental computation Incremental computing, also known as incremental computation, is a software feature which, whenever a piece of data changes, attempts to save time by only recomputing those outputs which depend on the changed data. When incremental computing is su ...

and single instruction multiple data (SIMD) techniques along with appropriate intrinsic instructions.

References

{{Reflist

External links

NNUE
on the Chess Programming Wiki.
NNUE evaluation functions for computer shogi
on

github.com GitHub, Inc. () is an Internet hosting service for software development and version control using Git. It provides the distributed version control of Git plus access control, bug tracking system, bug tracking, software feature requests, task man ...

Evaluation methods Neural networks Japanese inventions Computer shogi Computer chess

See also

References

External links