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Installing dependencies

Note

Before proceeding, send Yipeng or Manuel an SSH key to your system so that we can give you read/write permission to julian, the git-annex server where our ntuples are stored.

Clone the repository and set up the annex component1. We have a private server, julian, that hosts git-annex files.

git clone git@github.com:umd-lhcb/lhcb-ntuples-gen
cd lhcb-ntuples-gen
#git remote add julian git@lhcb.physics.umd.edu:lhcb-ntuples-gen  # not needed unless you want to copy to julian
git remote add glacier git@10.229.60.85:lhcb-ntuples-gen
git annex init --version=7
git submodule update --init  # Do this before git annex sync to avoid potential mess-up of submodule pointers!
git annex sync

# It is higly recommended to install nix now before proceed! See below for some pointers on how to do it
# If you have nix installed:
#   nix develop
make install-dep

Note that these commands will only initialize the files controlled by git-annex (several GB in total) with symbolic links. You typically will download individual files as you need them with 

git annex get <path_to_file>

The set up above also installs in the lib/python/ folder pyBabyMaker, pyTuplingUtils, and other packages that are needed. Each commit of lhcb-ntuples-gen points to specific commits of these packages. Thus, every time you pull new code in lhcb-ntuples-gen, you need to make sure you have the appropriate commits of the other packages installed with

Note

Don't forget to type nix develop before typing make install-dep, if you have nix installed!

git pull
git submodule update --init --recursive
make install-dep

Install docker to run DaVinci locally

We use docker to run a pre-built DaVinci image locally. To install docker:

On Arch Linux run sudo pacman -S docker and follow this Arch wiki entry to finish the setup.

In macOS with an Intel processor, you can install Docker by downloading it from their official site. You will need to log in to a Docker account and have it running to be able to pull the image.

In macOS with an ARM processor docker has problems, but you install colima instead

brew install docker docker-compose docker-machine colima

colima stop
colima delete # delete existing instance
# Start with Rosetta 2 emulation
colima start --arch aarch64 --vm-type=vz --vz-rosetta --cpu 4 --memory 8 --disk 120

Now it's time to pull (download) the pre-built DaVinci docker: 

docker pull umdlhcb/lhcb-stack-cc7:DaVinci-v45r6-SL

Install nix

All of our C++ dependencies are installed with nix. To install nix, refer to the guide in root-curated repo.

Warning

nix develop also provides a Python virtualenv. It is located in .virtualenv in project root.

If a major update in nixpkgs occurs, Python may also get a significate update (e.g. Python 3.8 -> Python 3.9). In this case, the virtualenv may stop working.

In any case, if you see any weired Python problem, simply delete the .virtualenv folder, then run nix develop again: A new virtualenv will be re-created.

babymaker code

babymaker is part of the pyBabyMaker Python package. It requires python3 and a couple of Python dependencies3.

Note

It is strongly recommended to install clang-format4, so the generated C++ code looks much nicer.

pyBabyMaker is included in this project as a submodule. If you follow the project initialization procedure listed at the beginning of this instruction, you should already have it installed.

Info

For more info on local development of in-house Python modules (included as submodules), refer to this guide.

Install VCS (git and git-annex)

We use git to version-control the ntupling code and the wiki, and git-annex to version-control large files, mostly the input .dst files or important .root outputs. For more details on git-annex, see this brief introduction.

  • On Arch Linux, simply issue the following command to install both programs: 

    sudo pacman -S git git-annex

  • On macOS, if you have homebrew installed: 

    brew install git git-annex

  1. Windows filesystems don't support symbolic links, which makes git-annex almost unusable.

    Please use WSL or WSL2, and make sure the project is stored on a Linux file system! ↩

  2. gcc must be recent enough to support c++17 standard. Effectively, gcc6 or clang5 (or newer) is required.

    In reality, you typically don't need to worry about this, as nix develop will prepare you a shell with almost all tools needed for this project. ↩

  3. These dependencies are listed in <project_root>/requirements.txt. It is highly recommended to install pip to manage Python packages.

    Note that pyBabyMaker doesn't rely on ROOT at all.

    It is also highly recommended to use pyenv and pyenv-virtualenv to manage Python enviroments. Please google the installation instructions for your OS. ↩

  4. clang-format usually comes with clang. A notable exception is on macOS. In that case, just type in brew install clang-format. ↩