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Bread Engine 1.5.5 - new version chess engine (Pre-release)

 
A new version of the chess engine has just been released – Bread Engine 1.5.0. Previous versions didn't break into the CEDR Top 64 chess engines and were ranked among amateurs. We'll see how this engine fares; the first tests will be held soon.

Bread Engine is a chess engine written in c++. It uses NNUE (efficiently updatable neural network) to evaluate positions, as well as minimax search. Bread engine does not have a GUI built in, however it supports the uci protocol, you can therefore run it on any chess GUI.
Author: Nonlinear2

What's new and key changes in the new version of the Bread Engine 1.5.5.

This is a bugfix release of Bread, that should no longer crash during engames. This version is also stronger than version 1.5.0 by around 40 elo, though i haven't ran a progression test.

Additions/Improvements:
better debugging features
added static exchange evaluation pruning to the main search
added the improving heuristic
Bug fixes:
fixed storing invalid evaluations in the transposition table when the only legal move is excluded
fixed singular beta going out of the legal evaluation range
fixed a search stack overflow

Bread Engine 1.5.0 ELO/Playing Strength improvements.

Bread Engine 1.5.0 is around 124 elo stronger than version 1.4.0 in STC and around 167 elo stronger in LTC.
These gains mainly come from new heuristics, better histories and bugfixes. The nodes per second in the bench command can no longer be negative (oops), and there sould be no more illegal pv lines.
The executable is also roughly two times smaller as the neural network weights are now embedded in their quantized integer type.
Additions/Improvements:
improve late move reductions (~10 elo)
switch to a quadratic razoring threshold (~16 elo)
refactor and improve root move ordering (~13 elo)
use static exchange evaluation in move ordering (~47 elo)
use an assembly incbin macro to embed the neural network in the executable
add and improve continuation history (~27 elo)
add singular extensions (~14 elo)

Testing the Bread Engine 1.5.0 chess engine.

STC: 8 + 0.08 s
Results of bread_engine_1.5.0 vs bread_engine_1.4.0 (8+0.08, NULL, NULL, UHO_2024_8mvs_big_+115_+134.pgn):
Elo: 123.55 +/- 14.22, nElo: 166.12 +/- 17.58
LOS: 100.00 %, DrawRatio: 32.67 %, PairsRatio: 5.39
Games: 1500, Wins: 817, Losses: 305, Draws: 378, Points: 1006.0 (67.07 %)
Ptnml(0-2): [19, 60, 245, 242, 184], WL/DD Ratio: 5.45
LTC: 40 + 0.4 s
Results of bread_engine_1.5.0 vs bread_engine_1.4.0 (40+0.4, NULL, NULL, UHO_2024_8mvs_big_+115_+134.pgn):
Elo: 167.53 +/- 21.02, nElo: 230.86 +/- 24.87
LOS: 100.00 %, DrawRatio: 25.60 %, PairsRatio: 8.30
Games: 750, Wins: 433, Losses: 97, Draws: 220, Points: 543.0 (72.40 %)
Ptnml(0-2): [2, 28, 96, 130, 119], WL/DD Ratio: 2.10

Bread Engine 1.4.0 vs other chess engines:

Quirky 1.03/14-814 Games
Leorik 3.1.3 JA2/14-1014 Games
Illumina 31/14-1214 Games
Tarnished 2.01/14-1214 Games
Calvin 6.1.0 JA0.5/14-1314 Games
Renegade 1.2.00.5/14-1314 Games
Knightx 4.45.5/13-213 Games
Kobra 2.0 JA9.5/12+712 Games
Prophet 4.4 JA8/12+412 Games
Zangdar 3.09.01 JA1.5/12-912 Games
Astra 5.20.5/12-1112 Games
Pawn 4.00/12-1212 Games
Halcyon 1 JA2/2+22 Games
Thorshammer 3.01 JA2/2+22 Games
Baislicka 1.0 JA2/2+22 Games
Eubos 4.01.5/2+12 Games
Olithink 5.11.21/2+02 Games
Critter 1.6a1/2+02 Games
Kobra 1.20.5/2-12 Games
Spaghet BologNNese 1.1.3 JA0.5/2-12 Games
EveAnn 3.10.5/2-12 Games


Bread Engine 1.5.5 download


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