shakmaty-syzygy
===============
A Rust library to probe Syzygy endgame tablebases, based on [shakmaty](https://github.com/niklasf/shakmaty).
[](https://travis-ci.org/niklasf/shakmaty-syzygy)
[](https://crates.io/crates/shakmaty-syzygy)
[](https://docs.rs/shakmaty-syzygy)
[Syzygy tables](https://syzygy-tables.info/#syzygy) allow optimal play under
the 50-move rule. Tables are available for positions with up to 7 pieces.
Example: Usage
--------------
```rust
use shakmaty::Chess;
use shakmaty::fen::Fen;
use shakmaty_syzygy::{Tablebase, Wdl, Dtz, Syzygy};
let mut tables = Tablebase::new();
tables.add_directory("tables/regular")?;
let pos: Chess = "8/8/8/8/B7/N7/K2k4/8 b - - 0 1"
.parse::<Fen>()?
.position()?;
let wdl = tables.probe_wdl(&pos)?;
assert_eq!(wdl, Wdl::Loss);
let dtz = tables.probe_dtz(&pos)?;
assert_eq!(dtz, Dtz(-59));
```
Example: Command line tool
--------------------------
A command line tool similar to [Fathom](https://github.com/basil00/Fathom):
```
$ cargo run --example fathom -- --path tables/regular -- "3qk3/8/8/8/8/8/8/4K3 w - - 0 1"
[Event "KvKQ"]
[Site ""]
[Date "????.??.??"]
[Round "-"]
[White "Syzygy"]
[Black "Syzygy"]
[Result "0-1"]
[FEN "3qk3/8/8/8/8/8/8/4K3 w - - 0 1"]
[Annotator "shakmaty-syzygy"]
[WDL "Loss"]
[DTZ "-16"]
[WinningMoves ""]
[DrawingMoves ""]
[LosingMoves "Kf1, Ke2, Kf2"]
{ KvKQ with DTZ -16 } 1. Ke2 Kd7 2. Kd1 Ke6+ 3. Kc1 Qd3 4. Kb2 Qd2+ 5. Ka1 Kd5 6. Kb1 Kc4 7. Ka1 Kb3 8. Kb1 Qd1# { Checkmate } 0-1
```
Documentation
-------------
[Read the documentation](https://docs.rs/shakmaty-syzygy)
Changelog
---------
* 0.12.1
- Update dependencies.
* 0.12.0
- Update shakmaty to `0.15`.
* 0.11.1
- Update dependencies.
* 0.11.0
- Update shakmaty to `0.14`.
- Add reimplementation of [Fathom](https://github.com/basil00/Fathom) as example.
* 0.10.0
- Update shakmaty to `0.13`.
- Use `FADV_RANDOM` on tablebase files.
* 0.9.0
- Update shakmaty to `0.12`.
- `Tablebase::add_directory()` now returns the number of added files.
- Added `Tablebase::add_file()`.
- `ProbeError` and `Metric` are now public. Other previously hidden APIs
are no longer exposed.
- Various refactorings, performance improvements and dependency updates.
* 0.8.1
- Optimize reading block lengths.
- More internal refactorings.
- Add benchmark.
* 0.8.0
- Update shakmaty to 0.11.x.
- Add `Syzygy::MAX_PIECES`.
- More efficient `Tablebase::best_move()`.
- Internal refactorings following tablebase rewrite in Cfish.
* 0.7.0
- Update shakmaty to 0.10.x.
* 0.6.0
- Update shakmaty to 0.9.x. Minimum Rust version is now 1.27.0.
* 0.5.2
- Fix `Wdl::from_dtz_after_zeroing(Dtz(100))`.
* 0.5.1
- Fix out of bounds panic when probing KPPPPPvK.
- Fix error when first group in giveaway should have had more than two
identical pieces.
- Only 6 pieces supported in antichess variants. Return
`SyzygyError::TooManyPieces` instead of potential panic.
* 0.5.0
- More contextual information for errors (table, backtrace,
invalid magic header bytes).
- Update to shakmaty 0.8.x.
- Provide a target for `cargo fuzz`. Fix several panics caused by
initializing and probing corrupted tables:
- Panic when reference pawn is missing.
- Panic when subtable material is not consistent with first file.
- Integer overflow when reading `symlen`.
- Integer overflow when `min_symlen` or `max_symlen` are out of bounds.
- Integer overflow when computing `block_length_size`.
- Stack overflow when recursively reading `symlen`.
* 0.4.5
- Make better use of `positioned-io` (cursor, remove `RandomAccessFile`).
* 0.4.4
- Remove work around from 0.3.1.
- Minor internal optimizations and cleanups.
* 0.4.3
- Fix DTZ off-by-one in some positions when there is mate in 1.
- Fix DTZ off-by-one in antichess endgames, when there is a threat to force
a capture leading to a blessed loss.
- Add `Tablebase::best_move()`.
* 0.4.2
- Fix DTZ in en passant positions.
- Minimum Rust version 1.26.0.
- Use guaranteed lossless versions from `u16` to `usize`.
- Provide i128 conversions for `Wdl` and `Dtz`.
* 0.4.1
- Fix debug assertion for `Dtz(0).add_plies()`.
* 0.4.0
- Update to shakmaty 0.7.x, which has bugfixes with regard to insufficient
material.
* 0.3.1
- Work around compiler bug in release mode.
* 0.3.0
- Rename `Tablebases` to `Tablebase`.
- Group file extension and magic as `TableType` in `Syzygy` trait.
* 0.2.2
- Implement support for wide DTZ values. These are required for some long
7 piece endgames.
- Fix panic on corrupted table.
* 0.2.1
- Should not panic on corrupted tables (even in debug mode).
- Switch from fnv to fxhash.
* 0.2.0
- Replace `Wdl::from(dtz)` with `Wdl::from_dtz_after_zeroing(dtz)`.
- Remove `isize` conversions of `Dtz` and `Wdl`.
- Fix WDL of lone king in atomic chess.
- Support stable rust.
* 0.1.4
- Fix ordering of lead pawns.
* 0.1.3
- Add support for Atomic chess and Giveaway.
* 0.1.2
- Cosmetic tweak to DTZ in case of mate in 1.
* 0.1.1
- Optional `serde-1` feature.
- Add `Dtz.add_plies()`.
* 0.1.0
- First release.
Acknowledgement
---------------
Thanks to Ronald de Man for his [Syzygy tablebases](https://github.com/syzygy1/tb).
The probing code is closely based on his implementation for Stockfish.
License
-------
shakmaty-syzygy is licensed under the GPL-3.0 (or any later version at your
option). See the COPYING file for the full license text.