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Koivisto v4.0
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@Luecx Luecx released this 09 Nov 19:01
· 834 commits to master since this release
v4.0
f2bbad6

Koivisto v4.0

A while ago, we released Koivisto v3.0 after a significant improvement in strength. It's time for another release again :)

We'd like to thank Andrew Grant for the OpenBench framework (and putting up with our questions about it!), without which we wouldn't be able to test so many new ideas; it has greatly improved our experimentation process since we started using it around Koivisto v2.0.
We'd also like to thank noobpwnftw for immense help with testing.

Our latest regression test shows significant Elo gain over Koivisto v3.0:

60+0.6:
ELO   | 141.20 +- 18.81 (95%)
SPRT  | 60.0+0.6s Threads=1 Hash=64MB
LLR   | 0.00 (-2.94, 2.94) [0.00, 0.00]
Games | N: 960 W: 501 L: 131 D: 328

15+0.1:
ELO   | 120.88 +- 13.38 (95%)
SPRT  | 15.0+0.15s Threads=1 Hash=16MB
LLR   | 0.00 (-2.94, 2.94) [0.00, 0.00]
Games | N: 1952 W: 1002 L: 349 D: 601

Furthermore, from cyclic time controls, one can expect significantly higher performance than before. Testing by CCRL members made issues apparent in how we handled cyclic time controls. This test shows the same version of the engine, but using the new cyclic time control manager.

40/15:
ELO   | 84.12 +- 20.83 (95%)
SPRT  | 40/15s Threads=1 Hash=16MB
LLR   | 3.11 (-2.94, 2.94) [0.00, 5.00]
Games | N: 640 W: 260 L: 108 D: 272

Changes

  • updated tt-usage.
  • does forced moves immediately.
  • added bishop pawn endgame relations evaluation term.
  • retuned entire evaluation with a larger dataset.
    • tuned mobility scores instead of computing them.
    • tuned king safety scores instead of computing them.
  • cleaned up the code and added comments.
  • asymmetric piece square tables based on king-king relation.
  • changed reduction/extension policy.
  • improved general time management.
  • fixed cyclic time management which leads to the engine using a lot more time in games with cyclic time controls.
  • fixed speed-related issues.
  • added a logo and banner.
Assets 8