Release notes
Sirius v8.0 is much stronger than the previous version. Many improvements to the search and evaluation were made, along with some QoL improvements, including pretty printing. Major changes include singular extensions, a much better correction history implementation, a rework of threats eval, and staged move generation. Sirius v8.0 is 200+ elo stronger than Sirius v7.0 on a balanced book.
Changelog
- Lots of refactors
- UCI changes
- Pretty printing
- perft and eval command
- Speedups
- Staged move generation
- Incrementally updated evaluation terms
- A few new evaluation features
- Horizontally mirrored piece-square tables
- Threats
- Complete rework
- Pawn push and king threats
- defended/weak threats
- King safety
- Pawn shield/storm rework
- Passed pawns
- Score based on whether push square is blocked/enemy attacked
- Minors behind pawns
- Bishop same color pawns
- Many search tweaks
- Best move stability time management
- Correction history
- Qsearch correction
- Many new tables besides pawn structure: minor/major piece, non pawn, material, and threats
- Singular extensions
- multicut, double extensions, and negative extensions
- Razoring
- Many other search changes
Self-play against Sirius v7.0
Elo | 212.25 +- 7.84 (95%)
Conf | 8.0+0.08s Threads=1 Hash=16MB
Games | N: 5004 W: 2946 L: 220 D: 1838
Penta | [2, 66, 489, 1094, 851]
Elo | 207.46 +- 16.39 (95%)
Conf | 40.0+0.40s Threads=1 Hash=64MB
Games | N: 1000 W: 564 L: 29 D: 407
Penta | [1, 5, 103, 240, 151]
Estimated 3450 rating
Credits
Thanks to members in the engine dev community who continue to support and discuss topics in computer chess with me
Selecting a binary
v1 is significantly slower than v2, v3, and v4(about 15x), and should only be used when absolutely necessary. In general, higher levels are faster.
If you download a binary and it crashes(closes immediately or doesn't respond to commands), it likely doesn't work, and you should download a different binary.
Full Changelog: v7.0...v8.0