Radiance Engine

⚡ Zig chess engine ⚡

Move Generation and Ordering

• Fancy Magic Bitboards
• Staged Move Generation
• Transposition Table Move Ordering
• Principal Variation Move Ordering
• Static Exchange Evaluation
• Chess960 support

Search

• Principal Variation Search
• Alpha-Beta Pruning
• Aspiration Window
• Late Move Reductions
• Null Move Pruning
• Reverse Futility Pruning
• Mate pruning
• Razoring
• Internal iterative reductions
• Quiescence Search
• Threefold Repetition
• Time Management

Evaluation

• Tuned Piece-square Tables
• AlphaZero Average Piece Values
• Tapered Evaluation
• Transposition Table Evaluation
• Endgame Heuristics
• Pawn Structures Heuristics
• Bishop pair bonus
• Mobility Bonus

Versions tournament

Time control: 120+1

CCRL blitz benchmark.

Rank	Name	CCRL	Elo	+	-	games	score	oppo.	draws
1	radiance_4.3		1961	10	10	6144	84%	1641	12%
2	radiance_4.2	1803	1803	8	8	6144	64%	1693	21%
3	radiance_4.1	1675	1640	8	9	7419	51%	1593	16%
4	radiance_4.0.1		1480	8	8	14312	65%	1249	8%
5	radiance_3.5	1322	1222	8	8	10216	66%	1025	11%
6	radiance_3.4	1300	1198	8	7	10218	64%	1028	11%
7	radiance_3.3		1146	8	8	10216	59%	1034	11%
8	radiance_3.2		1135	8	8	10215	58%	1036	11%
9	radiance_3.1.1	1119	965	8	8	9552	45%	1015	9%
10	radiance_3.0.1		689	9	9	9552	20%	1050	9%
11	radiance_2.4		647	9	9	9552	16%	1055	10%
12	radiance_2.3	874	602	9	10	9552	13%	1061	9%

Getting started

Compile and run

zig build run -release=fast

Deploy

zig build deploy

Test

zig build test --release=safe

UCI options

Name	Type	Default value	Valid values	Description
Hash	spin	256	[1, 65535]	Memory allocated to the transposition table (in MB).
Threads	spin	1	[1, 1]	Number of threads used to search.
Evaluation	combo	"PSQ"	["PSQ", "Shannon", "Materialist"]	Type of evaluation function.
Search	combo	"NegamaxAlphaBeta"	["NegamaxAlphaBeta", "Random"]	Type of search function.
UCI_Chess960	check	false	["true", "false"]

Commands

• uci
• isready
• setoption name <string> [value <string>]
• position [(fen <string> | startpos | kiwi | lasker) [moves <string>...]]
• eval
• go [movetime <int> | wtime <int> | btime <int> | winc <int> | binc <int> | nodes <int> | depth <int> | infinite | perft <int>]
• bench
• stop
• quit
• ucinewgame
• d

Archive

This project was originaly written in C++ before 4.0 version and archived under the name radiance_archived.

Aknowledgments

• Avalanche engine is a great example of how a zig project should be coded. Radiance engine still uses its pseudo random number generator (MIT License - Copyright (c) 2023 Yinuo Huang).
• Stockfish with its aggressive pruning methods.
• Chess Programming Wiki.

I'm radiant!