Devre

Devre is a strong open-source UCI-compatible chess engine written in C++. While writing the engine, I got great help from chessprogramming wiki, talkchess forum, Stockfish discord, and some open-source engines: Ethereal, Vice, and Koivisto.

Movegen

• Fancy magic bitboards
• legal movegen with make/unmake.

Search

• Alpha beta search (PVS)
• Quiessence search
• Transposition table
• Iterative Depening
• Aspiration Window
• Null Move Pruning
• Mate Distance Pruning
• Late Move Reduction
• Check Extension
• Futility prunings
• SEE pruning
• Singular Extension
• Correction History

Move ordering

• Hash move
• Good Captures sorted by Capture History
• Killer moves
• countermove
• History heuristic
• Bad Captures sorted by Capture History

Evaluation

Devre uses a NNUE for evaluation. The Network architecture is 768 -> (1536x2) -> 1. The default net was trained with Leela data. The training code is written in C/CUDA and can be found at https://github.com/OmerFarukTutkun/CUDA-Trainer. The training resources and other useful information about NNUE can be found in Stockfish Discord. Thanks to the Stockfish and Leela teams for publishing their training data publicly.

Compiling

To compile in Linux/Windows with a CPU that supports AVX512/AVX2/SSSE3:

• to compile with makefile you can use one of the options: make make build=avx512 make build=avx2 make build=ssse3