Radiance Engine

⚡ Zig chess engine ⚡

Move Generation and Ordering

• Fancy Magic Bitboards
• Staged Move Generation
• Fancy Magic Bitboards For Sliders
• Transposition Table Move Ordering
• Principal Variation Move Ordering
• MVV-LVA
• Chess960 support

Search

• Principal Variation Search
• Alpha-Beta Pruning
• Aspiration Window
• Late Move Reductions
• Null Move Pruning
• Reverse Futility Pruning
• 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
• Mobility Bonus

Versions tournament

Time control: 120+1

CCRL blitz benchmark.

Rank	Name	CCRL	Elo	+	-	games	score	oppo.	draws
1	radiance_4.1		1733	47	43	322	88%	1343	10%
2	radiance_4.0.1		1591	10	10	9618	91%	1059	6%
3	radiance_3.5	1326	1326	8	8	9616	70%	1092	11%
4	radiance_3.4	1300	1302	8	8	9616	68%	1095	11%
5	radiance_3.3		1250	8	7	9615	63%	1101	11%
6	radiance_3.2		1239	8	7	9615	62%	1103	12%
7	radiance_3.1.1	1116	1070	8	8	9552	45%	1120	9%
8	radiance_3.0.1		793	9	9	9552	20%	1155	9%
9	radiance_2.4	866	751	9	9	9552	16%	1160	10%
10	radiance_2.3	865	707	9	9	9552	13%	1166	9%

Getting started

Compile and run

zig build run -relase=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 <id> [value <x>]
• position [fen <string> | startpos | kiwi | lasker] [moves <string>...]
• eval
• go [movetime <int> | [wtime <int>] [btime <int>] [winc <int>] [binc <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!