Chess engine: Cheers 0.3.0

 

This is the first release of Cheers, providing a reasonable strength on a single thread

Rating CEDR=2485  Author: Algorhythm

v.0.3.0:

This version features a ground-up rebuild of the evaluation function for a significant strength improvement over version 0.2.2

STC:

ELO   | 206.78 +- 10.22 (95%)

CONF  | 8.0+0.08s Threads=1 Hash=8MB

GAMES | N: 5000 W: 3446 L: 778 D: 776

LTC:

ELO   | 241.04 +- 10.46 (95%)

CONF  | 60.0+0.60s Threads=1 Hash=64MB

GAMES | N: 5000 W: 3568 L: 566 D: 866

These self-play results are likely inflated, and comparing Cheers 0.3.0 to other engines will result in smaller Elo gains over 0.2.2.

Evaluation data

On top of creating a stronger evaluation function with the existing dataset, the open lichess-big3-resolved dataset was incorporated for another large strength increase.

Bugfixes

This release fixes a long-standing 'bug' in the reporting of castling moves in regular chess vs. chess960. cutechess-cli, a de-facto standard of sorts, will accept 960-style castling (king takes friendly rook) regardless of the UCI_Chess960 setting, but other programs will crash if regular castling (king moves 2 squares) is not used. #2

This release properly respects the UCI_Chess960 setting and will report castling correspondingly. As to what the 'correct' behaviour should be, it is underspecified in the UCI documentation.

Rating CEDR progres - Cheers.

Pl	Engine	Rating	Score	Games	%
1256	Cheers 0.1	2485.2	31.00	100	31.00
1380	Cheers 0.2.2	2289.9	18.50	100	18.50
1442	Cheers 0.2	2161.4	2.50	32	7.81
1472	Cheers 0.2.1	2081.8	1.50	33	4.55

Cheers 0.3.0 download