Crystal 8

Resolved a couple of minor but longstanding issues.
Adopt SF eval.
Reworked TT damping.
Merged in upstream from Stockfish.
Implemented contempt.
Singular extensions adjustment.
Improved king danger functionality.
Small pruning adjustments.

Bench: 20049890

Crystal 7 CMB

Various cleanups, consolidations, and simplifications

Extend supported depth

Improved progress detection

Improved TB efficiency

Bench: 7393911

Additional compiles courtesy of IpMan may be found at: https://ipmanchess.yolasite.com/compiles.php

Crystal 6 PMT

Bug fix for reductions.

Improvements to prob cut logic.

Improved NMP safety.

Score now weighted on traditional values.

New, more efficient TB handling in certain situations.

Introduced framework for future development based on first principles.

Restored some reductions/extensions from Stockfish.

Merged upstream changes from Stockfish.

Bench: 9298798

Additional compiles by Ipman may be found at: https://ipmanchess.yolasite.com/compiles.php

Crystal 5 KWK

Improvements to mate finding & progress detection.

Relative strength increase on top of upstream improvements is ~10 Elo.

Bench: 5390492

Compiles courtesy of IpMan: https://ipmanchess.yolasite.com/compiles.php

Crystal v4.1

Includes a number of bugfixes, search enhancements, and upstream merges.

Cursed/Blessed tablebase results are now displayed as scores in the 80's range when the 50 move rule is disabled in order to distinguish them from regular TB hits which continue to be scored in the 90's.

Bench: 6485199

Compiles by IpMan: https://ipmanchess.yolasite.com/compiles.php

Crystal v4.0

This update encompasses many changes from both upstream and original work. Effort has been put into narrowing the tree without sacrificing tactical ability, thus improving scaling. While it should remain a fair bit weaker than default Stockfish, the relative Elo gap has hopefully been lessened and general strength improved.

Bench: 5405822

Additional compiles by IpMan may be found at: http://ipmanchess.yolasite.com/compiles.php

Crystal v3.2

Small pruning and LMR adjustments.
Added NNUE scaling.
Merged upstream.

Bench: 8708696

Compiles courtesy of IpMan may be found at: http://ipmanchess.yolasite.com/compiles.php

Crystal v3.1

False mate bugfix from upstream.
Code cleanup & pruning enhancements.
Improved progress scoring.

Bench: 7950574

Compiles courtesy of IpMan may be found at: http://ipmanchess.yolasite.com/compiles.php

Crystal v3.0

Numerous fixes since v2.0.
Introduction of eval smoothing.
Introduction of NNUE.

Bench: 6080718

Crystal v2.0

King danger search enhancements

Bench: 10718459

Compiles by IpMan: http://ipmanchess.yolasite.com/compiles.php