🦈 IMP: Accurate SEE (Static Exchange Evaluation)

[TheBlackPlague]

🎯 Summary

This PR removes the Approximation function used for Static Exchange Evaluation (SEE) pruning with an Accurate function. The goal is that this allows for a deeper understanding of good and bad captures, avoiding bad captures that may seem good initially.

The algorithm used is the SWAP Algorithm.

The implementation changes the SEE Pruning currently done in QSearch to use the Accurate function instead of the Approximate one.

👏 Acknowledgements

• Jay Honnold: The algorithm implementation is largely inspired by Jay's implementation of the algorithm. Kudos, Jay. 🙌

📈 ELO

STC:

ELO   | 21.32 +- 9.75 (95%)
SPRT  | 10.0+0.10s Threads=1 Hash=16MB
LLR   | 2.98 (-2.94, 2.94) [0.00, 5.00]
GAMES | N: 2480 W: 706 L: 554 D: 1220

LTC:

ELO   | 18.56 +- 8.99 (95%)
SPRT  | 60.0+0.60s Threads=1 Hash=256MB
LLR   | 2.96 (-2.94, 2.94) [0.00, 5.00]
GAMES | N: 2848 W: 782 L: 630 D: 1436