Pawn 4.0 - UCI chess engine

Pawn - UCI alpha-beta chess engine, largely inspired by Stockfish.
Author: Rui Coelho.  Rating CEDR=3541

v.4.0:

The majority of the strength gains in this release are related to the improved NNUE, which results from refining the training procedure and the dataset generation strategy. Some minor search tweaks have also been explored.

The training data used for training is now freely available at HuggingFace. As usual, all data generation and training have been done with the tools in the branch data_gen, and the provided datasets are stored using pawn's data format (source).

Git tags are now used to describe development builds (via the git describe command), and many tests have been added to run pawn under different compiler sanitisers and Valgrind. The threading model has also been refactored to ease concurrent data generation for the NNUE.

In self-play at LTC conditions, the new version is roughly 40 Elo stronger and wins 4.6 more game pairs on average than it loses.

LTC vs pawn 3.0:

Games: 2000/2000 Elo diff: 43.48 [37.10, 49.89] (95%)

W: 336 L: 87 D: 1577 Draw ratio: 78.8%

Pntl: [0, 61, 645, 278, 16]

No functional change

Pawn 3.0 vs other engines:

Minic 3.41	17.5/36	-1	36 Games
Uralochka 3.41 dev1	8.5/30	-13	30 Games
Caissa 1.16	6/28	-16	28 Games
Texel 1.11	13/26	+0	26 Games
Arasan 24.1	11/26	-4	26 Games
Midnight 9	12.5/22	+3	22 Games
RubiChess 20240112	7/20	-6	20 Games
Obsidian 10.0	6.5/20	-7	20 Games
Fatalii 0.6.0	14/14	+14	14 Games
Critter 1.6a	11.5/14	+9	14 Games
Counter 5.5	10/14	+6	14 Games
Avalanche 2.1.0	9.5/14	+5	14 Games
Booot 7.3	5.5/14	-3	14 Games
Stormphrax 4.0.0	5.5/14	-3	14 Games
Seer 2.8.0	5/14	-4	14 Games
Clover 6.1	3.5/14	-7	14 Games
RofChade 3.1	3/14	-8	14 Games
Peacekeeper 2.30	7.5/12	+3	12 Games
Rice 8.0.0	6.5/12	+1	12 Games
Starzix 4.0	6.5/12	+1	12 Games
Polyfish 240114	3.5/12	-5	12 Games

Pawn 4.0 download

github:https://github.com/ruicoelhopedro/pawn/releases/tag/v2.0