Vatu

Dumb chess engine written in Rust for fun.

Features

• UCI
• Barely optimized board, position and moves representations
• Simple negamax for node evaluation
• Alpha-beta search tree pruning for speeding searches

Last time I checked it ran approximately at 10000 nps.

Thanks to UCI the bot can run with most compatible software; Cutechess has been used for testing.

Usage

Build

With Cargo:

cargo build --release

With Docker, to avoid setting up a Rust toolchain:

docker build -f res/docker/Dockerfile -t vatu-builder --target builder .
docker create vatu-builder  # Returns a container ID.
docker cp <id>:/src/target/release/vatu .
docker rm <id>
docker rmi vatu-builder

Run

If you built it with Cargo, the binary is in target/release.

./vatu

To run your own instance of the bot on Lichess (why would you do that?), create a bot account and get an OAuth token. Then using the full Docker image:

# Fetch the lichess-bot submodule.
git submodule update --init --recursive
# Copy the config.yml template to your own copy and modify it.
cp external/lichess-bot/config.yml.example /tmp/vatu-config/config.yml
# Build the image. Make sure config.yml is not there to not embed it!
docker build -f res/docker/Dockerfile -t vatu .
# Run with the config folder mounted at /config.
docker run -v /tmp/vatu-config:/config -ti vatu
# In the container, use the following command:
python lichess-bot.py --config /config/config.yml

TODO

• Support time constraints
• Unmake mechanism instead of allocating nodes like there is no tomorrow
• Precompute some pieces moves, maybe (done for knights)
• Transposition table that does not actually slows search down
• Check Zobrist hashes for previous point
• Actual bitboard
• Some kind of move ordering could be great
• Multithreading (never)