Chess engine: Fatalii 0.6.0

Fatalii - UCI chess engine

Author: Patrick Heck,  Rating CEDR=2388

v.0.6.0:

Search

Switch from fail-hard to fail-soft alpha-beta search

Add static exchange evaluation (SEE)

Use SEE for move ordering

Skip losing captures in quiescence search

Use subtree size for root move ordering

Add check extensions

Add delta pruning in quiescence search

Use futility and reverse futility pruning at depths > 1

Add late move reductions

Improve null move pruning

Only do null move pruning if the static evaluation is greater than or equal to beta

Do not play 2 null moves in a row

Reset killers for the next ply before playing a move

Persist history table between searches

Play forced moves immediately, without searching depth 1 (searching depth 1 has sometimes led to weird eval jumps)

Tune search parameters

Time management

Make better use of the given time in games with increment

UCI

Include seldepth in UCI info

No longer print the last uci info twice

Bugfixes

Fix replacement scheme in transposition table (could cause duplicate entries)

Disable reverse futility pruning in PV nodes (could lead to missing checkmates)

Match against previous version

Chess960, 8s + 0.08s

Score of Fatalii 0.6.0 vs Fatalii 0.5.0: 265 - 113 - 122  [0.652] 500

...      Fatalii 0.6.0 playing White: 140 - 52 - 58  [0.676] 250

...      Fatalii 0.6.0 playing Black: 125 - 61 - 64  [0.628] 250

...      White vs Black: 201 - 177 - 122  [0.524] 500

Elo difference: 109.1 +/- 27.4, LOS: 100.0 %, DrawRatio: 24.4 %

Rating CEDR progres - Fatalii

Pl	Engine	Rating	Score	Games	%
1618	Fatalii 0.5.0	2388.6	44.50	340	13.09
1687	Fatalii 0.2.1	2290.7	6.50	64	10.16
1746	Fatalii 0.4.0	2173.4	12.50	86	14.53
1756	Fatalii 0.2.0	2163.6	3.50	74	4.73
1759	Fatalii 0.3.0	2161.7	9.00	82	10.98
1789	Fatalii 0.3.1	2084.5	13.00	155	8.39
1962	Fatalii 0.1.2	1420.5	0.50	26	1.92

Fatalii 0.6.0 download