Conan package manager is a widely-used package manager for large C++ projects. The benefits of using Conan, in the contrary to Spack, is the third-party packages are attached with the individual project, instead of an environment. Therefore, users don't need to go into a specific environment to use the packages. For more information, please refer to the Conan Documentation.

Setup the project with Conan

First make sure you have installed and updated the git submodule. If not, run the following command:

git submodule update --init --recursive

Then configure CMake and build the project

export SIMPATH=%PATH_TO_FAIRSOFT%
export FAIRROOTPATH=%PATH_TO_FAIRROOT%
# from %R3BRoot_DIRECTORY%
cmake --preset default
cmake --build --preset default -- -j${number_of_threads}
source build/config.sh

Use Ninja

By default, CMake uses "Gnu Makefile" to build the project under the hood. However, "Gnu makefile" is pretty slow and it's recommended to use "ninja" if ninja is available in your system. To do this, instead run the configuration step with:

cmake --preset default -Gninja

or put the following command in the .bashrc (or .zshrc if zsh is used):

export CMAKE_GENERATOR=Ninja

Add third-party packages

Adding a package to the project is pretty easy. Suppose you want to use Eigen library (a famous linear algebra library used by Tensorflow) to R3BRoot. First go to the conan center and search for "eigen". You would find an entry related to "eigen/3.4.0", which contains further instructions how to add the package to your project. Under the "conanfile.py" tab, you could find a call to self.requires. Add this line to the conanfile.py located at the R3BRoot root folder:

def requirements(self):
    # other packages
    self.requires("eigen/3.4.0")

Be aware that you shouldn't change other variables like "settings" or "generators".

Then in the CMakeLists.txt, add

if(CONAN_ENABLED)
    find_package(Eigen3 REQUIRED)
endif()

and link this target to your executable or library. See CMake usage about CMake target linkage.