Chess engine: Alexandria 2.3.1 NNUE

- July 25, 2022

Chess engine: Alexandria

Author: Normand M. Blais Rating CEDR=2847

v.2.3.1

What's Changed

Use a conditional jump when the position is in check by @PGG106 in #11

Implement improving variable and reduce fut margin by @PGG106 in #12

IIR by @PGG106 in #13

Tweak Aspiration windows by @PGG106 in #14

Change the way the TT is probed by @PGG106 in #16

The last (known) bug that has ever plagued alexandria has been fixed, some minor search fixed were made, this release should gain 30-40 elo against the non shadowdropped release of 2.3 and 10-20 against the shadowdropped one.

As it stands this is Alexandria's final release. Tt's been a fun journey and i'm happy with how strong it is, but testing became frankly usufferable and there are no new ideas that i fully understand and that i'm capable of implementing, good luck to anyone that'll ever work on an engine ;).

Alexandria 2.3.1 NNUE download

Individual statistics: Alexandria 2.1.0 - 75 games CEDR (+ 11,= 19,- 45), 27.3 %

Fritz 17 : 6 (+ 0,= 5,- 1), 41.7 %
Stockfish 15 : 6 (+ 0,= 1,- 5), 8.3 %
Fisherov 0.98k : 5 (+ 1,= 0,- 4), 20.0 %
Wasp 5.50 : 1 (+ 0,= 0,- 1), 0.0 %
Arasan 23.3 : 5 (+ 0,= 0,- 5), 0.0 %
Black Marlin 5.0 : 1 (+ 0,= 0,- 1), 0.0 %
ChessKISS 1.8 : 4 (+ 4,= 0,- 0), 100.0 %
Rebel 15x2 : 1 (+ 0,= 0,- 1), 0.0 %
Berserk 9-dev3 : 2 (+ 0,= 0,- 2), 0.0 %
StockfishMZ Iccf 240522 : 4 (+ 0,= 0,- 4), 0.0 %
Fritz 15 : 1 (+ 0,= 0,- 1), 0.0 %
Protej 0.6.3 : 1 (+ 1,= 0,- 0), 100.0 %
Crystal 060622 : 2 (+ 0,= 1,- 1), 25.0 %
Berserk 9 : 2 (+ 0,= 0,- 2), 0.0 %
Journeyman 2.1 : 6 (+ 0,= 5,- 1), 41.7 %
Fisherov chess monk 1.2 : 2 (+ 0,= 0,- 2), 0.0 %
CorChess 210622 : 6 (+ 0,= 0,- 6), 0.0 %
Gargantua 1.0 : 7 (+ 1,= 2,- 4), 28.6 %
Smallbrain 4.0 : 7 (+ 0,= 3,- 4), 21.4 %
Odonata 0.6.2 : 6 (+ 4,= 2,- 0), 83.3 %

Our social media: