NNUE chess engine written in Rust. Play against it on lichess.org
The current minimum supported Rust version for the UCI binary is 1.59.0.
- Frozenight 6.0: 3226
- Frozenight 5.1: 3027
- Frozenight 5.0: 3000
- Frozenight 4.0: 2964
- Frozenight 3.0: 2842
- Frozenight 2.1: 2680
- Frozenight 2.0: 2614
- Frozenight 6.0: 3331
- Frozenight 5.1: 3098
- Frozenight 5.0: 3085
- Frozenight 4.0: 3005
- Frozenight 3.0: 2891
- Frozenight 2.1: 2677
- Frozenight 1.0: 2448
- Frozenight 6.0: 3493
- Frozenight 5.1: 3148
- Frozenight 5.0: 3103
- Frozenight 4.0: 2994
- Frozenight 3.0: 2761
cozy-chessfor move generation- Principal Variation Search
- Aspiration windows
- LazySMP multithreading
- NNUE evaluation
- 768 -> 384x2 (-> 1)x16
- Network bucketing based on modified piece material values (Queen = 8)
- This is based on game phase tuning in Koivisto done by Luecx
- Training data generated through self-play, originally starting with a random network
- Trained using (a modified version of) Pali's
marlinflow
- Quiescense search
- SEE ordering & pruning with MVV-LVA for ties
- Check Evasions
- Check Extensions
- PV Extensions
- Late move reductions
- Late move pruning
- Null move pruning
- Reverse futility pruning, except using qsearch instead of static eval
- Internal Iterated Deepening
- Transposition Table
- Depth-preferred with aging
- Move ordering
- Hash move
- SEE captures, losing captures last, with MVV-LVA for ties
- Killer heuristic (ordered near pawn captures pawn)
- Relative history heuristic (side-by-side piece-tosq and fromsq-tosq tables)
- Underpromotions last
- Time management
- Uses at least 2% remaining + increment/2
- Avoids stopping in the middle of an iteration
Frozenight is dual-licensed under the MIT License and Apache License (Version 2.0) licesnses.
- Analog (Tantabus), for
cozy-chessand helping me understand search techniques - Pali (Black Marlin), for
marlinflowand helping me understand NN training and search techniques - Authors of the chess programming wiki, for its wealth of knowledge