🔍 SEE pruning

[eduherminio]

Preconditions in outer conditional:

!pvNode && !isInCheck && isNotGettingCheckmated
    && moveScores[moveIndex] < EvaluationConstants.PromotionMoveScoreValue   // bad captures and quiets

Simplest version: if (!SEE.HasPositiveScore(position, move))

Test  | search/see-pruning
Elo   | -219.81 +- 37.05 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | -1.52 (-2.25, 2.89) [0.00, 3.00]
Games | 334: +29 -216 =89
Penta | [70, 56, 33, 7, 1]
https://openbench.lynx-chess.com/test/816/

High negative threshold: -1000

Test  | search/see-pruning
Elo   | -85.87 +- 18.14 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | -2.03 (-2.25, 2.89) [0.00, 3.00]
Games | 710: +122 -294 =294
Penta | [50, 129, 122, 51, 3]
https://openbench.lynx-chess.com/test/817/

Threshold: -100 * depth

Test  | search/see-pruning
Elo   | -68.20 +- 18.90 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | -1.47 (-2.25, 2.89) [0.00, 3.00]
Games | 614: +113 -232 =269
Penta | [39, 92, 130, 41, 5]
https://openbench.lynx-chess.com/test/818/

Depth: <= 5 && Threshold: -100 * depth

Test  | search/see-pruning
Elo   | -23.58 +- 12.31 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | -1.21 (-2.25, 2.89) [0.00, 3.00]
Games | 1284: +323 -410 =551
Penta | [39, 180, 270, 135, 18]
https://openbench.lynx-chess.com/test/819/

Depth: <= 5 && Threshold: -99 * depth

Test  | search/see-pruning
Elo   | -37.78 +- 17.05 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | -1.07 (-2.25, 2.89) [0.00, 3.00]
Games | 794: +175 -261 =358
Penta | [32, 131, 141, 77, 16]
https://openbench.lynx-chess.com/test/820/

Depth: <= 5 && Threshold: -99 * depth for noisy, -50 * depth for quiet

Test  | search/see-pruning
Elo   | -53.50 +- 19.39 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | -1.20 (-2.25, 2.89) [0.00, 3.00]
Games | 648: +135 -234 =279
Penta | [38, 102, 113, 63, 8]
https://openbench.lynx-chess.com/test/822/