Chess engine: Patricia 2.0.1

Patricia - UCI chess engine

Author: Adam Kulju

A chess program made with the goal of objectifying chess style, and then training networks to excel at said style.

v.2.0:

Estimated CCRL Rating: 3100-3150

Patricia 2.0 is, per the EAS tool, unquestionably the most aggressive superhuman chess engine ever created (and the most aggressive engine of any kind that I currently know of).

She's also significantly stronger than her 1.0 version, with a larger net and several search features added in to make up for the loss in strength resulting from all the sacrifices.

Comparison of EAS testing of Patricia 1.0 and Patricia 2.0:

Rank  EAS-Score  sacs   shorts  draws  moves  Engine/player 

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   1    185033  22.05%  25.03%  12.30%   65   Patricia 1.0

   2    125386  15.95%  26.71%  19.36%   64   Peacekeeper 1.50  

   3     92720  15.06%  13.10%  15.62%   70   Willow 2.8  

   4     73207  10.61%  14.76%  20.66%   71   Midnight v5  

   5     70947  10.33%  12.76%  19.66%   71   Wahoo v3  

   6     67964  11.17%  15.28%  21.25%   70   Polaris 1.6.1  

   7     56034  04.03%  16.76%  27.24%   68   Akimbo 0.4.1  

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Rank  EAS-Score  sacs   shorts  draws  moves  Engine/player 

-------------------------------------------------------------------

   1    424440  35.61%  42.62%  04.14%   54   Patricia 2.0

   2    124856  14.06%  29.40%  21.97%   64   Peacekeeper 1.50  

   3     87869  17.11%  13.84%  18.57%   69   Willow 2.8  

   4     86016  09.09%  18.59%  17.44%   70   Midnight v5  

   5     74072  10.58%  14.96%  19.22%   71   Wahoo v3  

   6     63659  10.23%  14.82%  21.19%   71   Polaris 1.6.1  

   7     49836  02.86%  17.32%  29.43%   67   Akimbo 0.4.1  

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Details of what exactly Patricia's featureset is can be found in Patricia's README. The whole evaluation/evaluation adjustment function was scrapped and rewritten, and all search features aside from LMR, RFP, and NMP were added between 1.0 and 2.0.

Binaries

Linux and Windows binaries are found below. Use v3 (avx2) for most computers, and use v2 (SSE) for very old models. If you're not sure about which one to download, try v3 first.

If you have a machine that supports AVX512 or you want to compile from source for other reasons, you can easily build Patricia from source by running the commands:

git clone https://github.com/Adam-Kulju/Patricia

cd Patricia/engine

make -B

The executable patricia will be found in the current directory, that is, Patricia/engine.

bugfix:

I've received several reports of bugs causing Patricia to crash. While I could not get Patricia to actively crash on my machine, I did find some undefined behavior and memory errors; they are all cleaned up now, as Patricia passes valgrind and AddressSan checks on high depth searches on my machine, in both Windows and Linux, without any issue. Updated executables are found here. Please notify me if problems continue.

Update (4/6/2024): Fixed hash setting bug as well.

No other functional change.

Patricia 2.0.1 download