Crate alcibiades

Expand description

This crate provides a framework for writing chess engines.

§Why chess engines?

Simple! Chess is the greatest thing humans have invented. Computers follow closely ;)

§Why a framework?

There is lots of knowledge out there about how to write a chess engine, and there is a lot of room for innovation also. Writing a chess engine is fun, but even for the simplest engine there is a lot of complex (and boring) things that have to be implemented first: the UCI protocol communication, the rules, the static exchange evaluator, and many more. Thousands of programmers have been re-implementing those things over and over again.

So, if you want to write your own chess engine, you face an unpleasant choice: You either roll up your sleeves and implement all the hard stuff from scratch, or you take someone else’s chess engine and struggle to understand its cryptic, undocumented source code, hoping that it will be general enough to allow modification. This unfortunate situation stifles innovation.

§Features

Modular design. Users can write their own implementations for every part of the chess engine.
Very good default implementations — move generation, quiescence search, static exchange evaluation, time management, iterative deepening, multi-PV, aspiration windows, generic transposition table.
Very complete UCI support (including “searchmoves”).

§Usage

This crate is on crates.io and can be used by adding alcibiades to your dependencies in your project’s Cargo.toml.

[dependencies]
alcibiades = "0.3.0"

and this to your crate root:

extern crate alcibiades;

Here is how simple it is to create a chess engine using this crate:

extern crate alcibiades;
use alcibiades::stock::*;
use alcibiades::engine::run_uci;

fn main() {
    type Ttable = StdTtable<StdTtableEntry>;
    type SearchNode = StdSearchNode<StdQsearch<StdMoveGenerator<SimpleEvaluator>>>;
    type SearchExecutor = Deepening<SimpleSearch<Ttable, SearchNode>>;
    run_uci::<SearchExecutor, StdTimeManager>("My engine", "John Doe", vec![]);
}

This engine is assembled from the “in stock” implementations of the different framework traits.

In reality, you will probably want to write your own implementations for some of the framework traits. Thanks to Rust’s incredible generic programming capabilities, you are not limited to implementing only the methods required by the traits. For example you may write your own static position evaluator which has a consult_endgame_table method. Then you will be able to write a search algorithm that uses this method.

§Speed and safety

This crate tries to be fast and memory-safe.

Modules§

bitsets: Defines constants and functions for working with bitboards.
engine: Implements a generic chess engine.
files: Defines a constant for each file on the board.
ranks: Defines a constant for each rank on the board.
squares: Defines a constant for each square on the board.
stock: Implementations of various traits.
utils: Defines generally useful functions and types.

Structs§

Board: Holds a chess position.
CastlingRights: Holds information about which player can castle on which side.
IllegalBoard: Represents an illegal position error.
Move: Represents a move on the chessboard.
MoveDigest: Encodes the minimum needed information that unambiguously describes a move.
PiecesPlacement: Describes how the pieces are placed on the board.
QsearchParams: Parameters describing a quiescence search.
RemainingTime: Describes the remaining time on the clocks.
SearchParams: Parameters describing a search.
SearchReport: A progress report from a search.
Variation: A sequence of moves from some starting position, together with the value assigned to the final position.

Enums§

OptionDescription: Describes a configuration option.

Constants§

Traits§

AddMove: A trait for adding moves to move containers.
DeepeningSearch: A trait for executing iterative deepening searches.
Evaluator: A trait used to statically evaluate positions.
MoveGenerator: A trait for move generators.
Qsearch: A trait for performing quiescence searches.
QsearchResult: A trait for quiescence searches’ results.
Search: A trait used to execute depth-first searches.
SearchNode: A trait for chess positions – a convenient interface for the tree-searching algorithm.
SetOption: A trait for announcing and changing configuration options.
TimeManager: A trait for deciding when the search must be terminated and the best move played.
Ttable: A trait for transposition tables.
TtableEntry: A trait for transposition table entries.

Functions§

get_option: Returns the current value for a given configuration option.

Type Aliases§

Bitboard: A set of squares on the chessboard.
BoundType: BOUND_EXACT, BOUND_LOWER, BOUND_UPPER, or BOUND_NONE.
CastlingSide: QUEENSIDE or KINGSIDE.
Color: WHITE or BLACK.
Depth: Search depth in half-moves.
MoveType: MOVE_ENPASSANT, MOVE_PROMOTION, MOVE_CASTLING, or MOVE_NORMAL.
PieceType: KING, QUEEN, ROOK, BISHOP, KINGHT, PAWN or PIECE_NONE.
Square: From 0 to 63 (0 is A1, 1 is B1, .. , 62 is G8, 63 is H8).
Value: Evaluation value in centipawns.

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