Lc0 — Building Lc0 version 0.30 on Debian 12

We have previously dedicated three blog posts in French on compiling the neural network chess engine Lc0 (Leela Chess Zero) on Ubuntu 18.04. A new version 0.30.0 has been released on July 21, 2023.

Here's the process to compile Lc0 on Debian 12 and Ubuntu 23.04.

Installing requirements

As a root user (or with sudo on Ubuntu):

apt update

apt install git build-essential meson

NVIDIA GPU Support

To compile Lc0 with the support for NVIDIA GPUs, you should add the two repositories non-free and contrib during the installation phase of prerequisites as described above.

As a root user (or with sudo on Ubuntu):

apt-add-repository non-free

apt-add-repository contrib

apt update

apt install nvidia-cuda-toolkit nvidia-cudnn

Building the source code

Navigate into the directory lc0 created by the previous command:

cd lc0

./build.sh

Testing

The executable lc0 generated by the build process can be found in the directory build/release/.

cd build/release/

Lc0 is a neural chess engine, requiring a pre-trained neural network for its operation. The simplest solution is to use the one from the official release (791556.pb.gz). It can be downloaded from the site https://training.lczero.org/networks/. For more information about available networks, see the website https://lczero.org/play/networks/bestnets/.

The pre-trained network file 791556.pb.gz can be downloaded using the following command:

wget https://training.lczero.org/get_network?sha=f404e156ceb2882470fd8c032b8754af0fa0b71168328912eaef14671a256e34 -O 791556.pb.gz

Once you have obtained the pre-trained network, you can run a benchmark with the following command:

./lc0 benchmark

You should see an output similar to this:

       _
|   _ | |
|_ |_ |_| v0.30.0 built Aug 28 2023
Found pb network file: ./791556.pb.gz
Creating backend [eigen]...
Using Eigen version 3.4.0
Eigen max batch size is 256.
    ...
    ...

If you compiled Lc0 with the support for NVIDIA GPUs (and have a compatible graphics card), you should see an output similar to this:

       _
|   _ | |
|_ |_ |_| v0.30.0 built Aug 28 2023
Found pb network file: ./791556.pb.gz
Creating backend [cudnn-auto]...
Switching to [cudnn-fp16]...
CUDA Runtime version: 11.8.0
Cudnn version: 8.5.0
Latest version of CUDA supported by the driver: 12.2.0
GPU: NVIDIA GeForce GTX 1650 Ti
GPU memory: 3.81238 GiB
GPU clock frequency: 1485 MHz
GPU compute capability: 7.5
    ...
    ...

The builds of Lc0 provided in this blog can be found on GitHub within the repository https://github.com/jldblog/lc0-linux-unofficial-builds.