Chess engine: Caissa 1.17

Caissa - UCI chess engine,  Author: Michał Witanowski

Rating CEDR=3655

v.1.17:

Progression test

TC=8+0.08, Book=UHO_Lichess_4852_v1.epd

Elo   | 20.60 +- 4.85 (95%)

Conf  | 8.0+0.08s Threads=1 Hash=8MB

Games | N: 9690 W: 2670 L: 2096 D: 4924

Penta | [38, 947, 2337, 1449, 74]

TC=60+0.6, Book=UHO_Lichess_4852_v1.epd

Elo   | 19.83 +- 6.47 (95%)

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

Games | N: 5000 W: 1272 L: 987 D: 2741

Penta | [4, 442, 1332, 709, 13]

TC=8+0.08, Book=DFRC.epd

Elo   | 15.59 +- 6.38 (95%)

Conf  | 8.0+0.08s Threads=1 Hash=8MB

Games | N: 4394 W: 948 L: 751 D: 2695

Penta | [28, 433, 1110, 566, 60]

Changes

New neural net trained on total 7.1B positions. Introduced more high quality games from SPRT tests to the dataset (~220M positions) and random endgame positions scored with 7-man TB (~40M positions). Finetuning previous net for over 50B iterations.

Small speedup

Search improvements:

Prevent search explosions in LMR

Simplify LMR history formula

Additional history bonus based on score difference

Store eval in TT as soon as possible

Higher RFP margin if opponent is threating a capture

Use threats info to generate less illegal king moves

Tweak transposition table replacement scheme

Caissa 1.16 - results:

RubiChess 20240112	11/18	+4	18 Games
Seer 2.8.0	9/16	+2	16 Games
Clover 6.1	8.5/15	+2	15 Games
Chess-System-Tal-2	8/15	+1	15 Games
Texel 1.11	9.5/12	+7	12 Games
Uralochka 3.41.dev1	7.5/12	+3	12 Games
Berserk 12.1	6.5/12	+1	12 Games
Obsidian 10.0	6.5/12	+1	12 Games
Koivisto 9.2	6/12	+0	12 Games
Ethereal 14.25	5.5/12	-1	12 Games
Avalanche 2.1.0	7.5/10	+5	10 Games
Stormphrax 4.0.0	6/8	+4	8 Games
Minic 3.41	6/8	+4	8 Games
Revenge 3.0	4.5/8	+1	8 Games
Minic 3.40	5.5/7	+4	7 Games
Uralochka 3.40a	5/7	+3	7 Games
Obsidian 9.0	4.5/7	+2	7 Games
Arasan 24.1	4.5/7	+2	7 Games
Rebel EAS	3.5/7	+0	7 Games
Pawn 3.0	5/6	+4	6 Games

Caissa 1.17 download