A UCI chess engine written in pure C++.
Focused on search strength, clean architecture, and informative UCI output.

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Overview

Elderviolet is a UCI-compatible chess engine implemented in pure C++ (no external dependencies).
It does not provide a GUI. To play or test the engine, connect it to a UCI GUI such as:

• Arena
• CuteChess / cutechess-cli
• BanksiaGUI
• ChessBase

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Features

Search & pruning:

• PVS
• Aspiration window
• LMR / LMP
• Null-move pruning
• Razor
• Futility pruning (incl. reverse futility)
• Mate distance pruning

Move ordering:

• Transposition table (TT) with mate score handling
• Killer moves
• History heuristic

Tactical filters:

• SEE pruning
• Full SEE fallback (see_full.h)

Parallel:

• Lazy SMP

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Build

This repository is header-heavy and uses main.cpp as the entry point.

Windows (MSVC)

Example (single translation unit build):

cl /O2 /std:c++20 /EHsc main.cpp

GCC / Clang

g++ -O3 -std=c++20 main.cpp -o Elderviolet

Tip: for local testing you can add native optimizations:

g++ -O3 -std=c++20 -march=native main.cpp -o Elderviolet

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Run (UCI)

Run the engine in a GUI, or from a terminal.

Example UCI session:

uci
isready
ucinewgame
position startpos moves e2e4 e7e5
go depth 12

Common options (depending on your build) are typically:

• Hash (MB)
• Threads

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Project Layout

Key files in the repository root:

• main.cpp — program entry point
• Engine.h — engine coordination / high-level interface
• uci.h — UCI protocol handling and option parsing
• Search.h — search (PVS, pruning, SMP)
• Evaluation.h — evaluation
• MoveGeneration.h — move generation
• Position.h — board representation / state
• Attack.h — attack tables / helpers
• TT.h — transposition table
• ZobristTables.h — hashing keys / tables
• see_full.h — full SEE implementation
• types.h — core types / constants
• logo.png — project logo

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Notes

• The engine binaries (*.exe) in this folder are build artifacts and may be platform/CPU specific (e.g. AVX2).
• For strength testing, prefer running matches with cutechess-cli and fixed settings.

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License

MIT License (see LICENSE).