The easiest way to use Korali is to launch it’s pre-built Docker container which provides Korali with all its dependencies already installed and configured. To launch the docker container, run:

docker run -it cselab/korali:latest

Manual Installation

Korali has been thoroughly tested on Linux (Ubuntu, Fedora) systems. Although it is possible to compile and run Korali on MacOS, we strongly recommend users to use the Docker image instead. Korali is not yet supported on Windows systems.

Below, we list the system requirements and steps to install Korali:

System Requirements

  • C++ Compiler

    Korali requires a C++ compiler that supports the C++17 standard (-std=c++17) to build. Hint: Check the following link to verify whether your compiler supports C++17. Korali’s installer will check the $CXX environment variable to determine the default C++ compiler. You can change the value of this variable to define a custom C++ compiler.

  • Git Client

    You need Git to clone (download) our code before installation.

  • meson

    To generate the installation configuration.

  • ninja

    To build Korali.

  • Python >=3.8

    Korali requires a version of Python higher than 3.8 to be installed in the system. Korali’s installer will check the python3 command. The path to this command should be present in the $PATH environment variable. Hint: Make sure Python3 is correctly installed or its module loaded before configuring Korali.

Installation Steps

  1. Download Korali

Download Korali with the following command:

git clone
  1. Setup Installation

To set up the compilation and installation, run:

cd korali
meson setup build --buildtype=release --prefix=PREFIX

where PREFIX is the absolute path where Korali will be installed. For example, use $HOME/.local/ to install it in the same folder where pip installs packages (this can be verified with python3 -m sysconfig | grep userbase). Optionally you can install Korali with support for MPI, OneDNN, and CUDNN, using the optional parameters:

cd korali
meson setup build --buildtype=release --prefix=PREFIX -Dmpi=true -Donednn=true -Dcudnn

A full list of installation options can be found in meson_options.txt. For more information, see Optional Requirements below.

  1. Build

To build Korali, run:

meson compile -C build
  1. Install

To install Korali, run:

meson install -C build

To uninstall Korali, run cd build && ninja uninstall or manually delete the folder containing the korali package.

  1. Setup environment

The LD_LIBRARY_PATH, PATH, PYTHONPATH environment variables need to be correctly setup for the linker to find the correct libraries at the moment of runtime. We provide a tool that facilitates this task:

source tools/env/ PREFIX


If you are experiencing problems installing or running Korali, please check the following hints:

  • Check Korali’s system requirements to verify that your system has all the required software components.

  • Check the build status to see if Korali is currently building correctly.

  • If the problem persists, please submit a new issue report on our Github repository detailing the problem, your system information, and the steps to replicate it and we will promptly address it.

  • For further questions, feel free to contact us.

Cray systems (Piz Daint)

Cray systems use a propietary build system that may cause conflicts with the default meson configuration when using MPI. To fix this, the following steps are recommended:

  1. Specify the cc and CC commands as default C and C++ compilers, respectively:

CC=cc CXX=CC meson setup build --buildtype=release --prefix=PREFIX
  1. It is possible tat the the default installation of mpi4py possibly uses a different MPI implementation than Korali, preventing multi-rank runs. To fix it, configure MPI compilers and reinstall mpi4py and Korali.

# Create wrappers `mpicc` and `mpic++` around Cray compilers `cc` and `CC`, respectively.
# Warning: this will overwrite any `mpicc` and `mpic++` in your `~/bin` folder!
mkdir -p $HOME/bin
echo -e '#!/bin/bash'"\n"'cc "$@"' > $HOME/bin/mpicc
echo -e '#!/bin/bash'"\n"'CC "$@"' > $HOME/bin/mpic++
chmod +x $HOME/bin/mpicc $HOME/bin/mpic++

# Load Python module (you can add this to your `~/.bashrc`).
module load cray-python

# Reinstall mpi4py locally and reinstall korali.
python3 -m pip install --user mpi4py --ignore-installed -v

Optional Requirements

  • oneDNN

    Korali uses the OneAPI Deep Neural Network Library for deep learning modules, and is disabled by default. You can enable it by adding the -Donednn=true option on the meson configuration line. To recommended configuration for oneDNN is:

  wget -O oneDNN-v2.2.2.tar.gz; \
  tar -xzvf oneDNN-v2.2.2.tar.gz; \
  mkdir -p "oneDNN-2.2.2/build"; \
  cd "oneDNN-2.2.2/build"; \
  CXXFLAGS=-O3 cmake .. \
   -DDNNL_ARCH_OPT_FLAGS='-march=native -mtune=native' \
   -DBUILD_SHARED_LIBS=true; make -j4; make install

- **CMake**
    Korali requires that you have `CMake <>`_ version 3.0 or higher installed in your system if you need it to install certain external libraries automatically.

- **MPI**
    One way to enable support distributed conduits and computational models is to configure Korali to compile with an MPI compiler. The installer will check the *$MPICXX* environment variable to determine a valid MPI C++ compiler.

- **MPI4Py**
    If you need to run Python-based MPI application as computational models in Korali, you will need to install the MPI4py python module, and install Korali via meson using the `-Dmpi4py=true` option.