Release v3.0.0 ⚔️

v3 is a near-complete rewrite of the evaluation and search. v2 was aggressive but bad at it: its attack bonuses double-counted, so it saw crushing attacks that weren't there and sacrificed into nothing. v3 is far stronger, but it still plays like Tal, and it was built to be fun to play against as a human.

What's new

• New evaluation: a sound core (PeSTO tables, pawn structure, mobility, threats, passed pawns, endgame knowledge) plus a Stockfish-style king-danger model. It knows a real attack from a fake one.
• "Tal mode" personality: values its attacks on your king at 180%, prefers keeping pieces on, avoids draws, and actively looks for sacrifices aimed at your king. It plays them when they're close to the best move. It makes about 2 sacrifices per game.
• Rewritten search: modern pruning and reductions tuned so sacrifices get searched deeply instead of being thrown away, plus better time management.
• Bug fixes: v2 could not find quiet sacrifices, stalemated opponents in won endgames, and sometimes played a different move from the one it was showing.

Results vs v2

• 40-game match: 39 wins, 1 loss, 0 draws
• Tactics test (11 positions, 2 s each): 10/11 (v2: 6/11)

UCI options

Only Threads and BookPath are exposed now. Everything else, including the personality, is fixed. Hash was removed and is fixed at 128 MB.

File

• aggro_chess.exe: precompiled UCI engine for Windows (64-bit). Put ph-gambitbook.bin next to it for the gambit opening book.