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 through Negamax
• Aspiration Window
• Late Move Reductions
• Late Move Pruning
• Null Move Pruning
• Reverse Futility Pruning
• Futility pruning
• Mate pruning
• Razoring
• Internal iterative reductions
• Quiescence Search
• Multi threading using lazy SMP
• 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_4.4		2243	14	14	3456	88%	1834	11%
2	radiance_4.3	2071	2071	9	9	7008	77%	1816	14%
3	radiance_4.2	1803	1917	8	8	7008	57%	1861	20%
4	radiance_4.1	1674	1754	8	8	8283	46%	1762	15%
5	radiance_4.0.1		1596	8	8	15176	61%	1413	8%
6	radiance_3.5	1321	1338	8	8	10216	66%	1141	11%
7	radiance_3.4	1299	1314	8	8	10218	64%	1144	11%
8	radiance_3.3		1262	8	8	10216	59%	1150	11%
9	radiance_3.2		1251	8	8	10215	58%	1152	11%
10	radiance_3.1.1	1117	1081	8	8	9552	45%	1131	9%
11	radiance_3.0.1		804	9	9	9552	20%	1166	9%
12	radiance_2.4		763	9	9	9552	16%	1171	10%
13	radiance_2.3	872	718	9	10	9552	13%	1177	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

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

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!