Building an ePIC Package

Overview

Teaching: 15 min
Exercises: 0 min

Questions

• How can I modify and build parts of the ePIC software stack inside eic-shell?

Objectives

• Download and build a package, set up the environment to use it.

Begin by obtaining the code of the repository you want to compile:

git clone git@github.com:eic/afterburner.git

Installing is now as easy as:

./build.sh afterburner

Note: You most likely will want to develop packages like epic, eicrecon, … Due to current technical issues, full compilation from scratch of these in the docker version of eic-shell on a Silicon Mac takes 15+ minutes, too much for this tutorial.

It is instructive to follow the steps that this script takes:

# ./build.sh afterburner
CMAKE COMMANDS:
========================================

[ generate buildsystem ]
cmake -S afterburner/cpp -B afterburner/build -DHEPMC3_ROOTIO=ON -DCMAKE_INSTALL_PREFIX=/Users/eickolja/eic/drich-dev/prefix

[ build ]
cmake --build afterburner/build -j4

[ install ]
cmake --install afterburner/build

========================================

This tells you almost everything the script does, and in fact if you make changes to a file or two, it can make sense to use these commands directly instead of running through the makefile generation step again.

[Add std::cout<<"Hello world 1" << std::endl; to afterburner/cpp/abconv/main.cc]
time ./build.sh afterburner

Then try

[Change "Hello world 1" to "Hello world 2"]
time cmake --build afterburner/build -j4 && cmake --install afterburner/build

Also, note in the above the appearance of -DHEPMC3_ROOTIO=ON. By default, build.sh can build anything that relies on the “cmake, make, make install” paradigm, but for some named packages, options can be added and changed by default, explore build.sh to learn more!

Finally, it is sometimes necessary, and it never hurts, to update the environment again, and we can learn from its output as well.

source environ.sh

Homework:

Install any of epic, EICrecon, etc. Make a change, recompile, see what happens! Suggestions: Add simple text output, change the parameters of a detector subsystem and look for the consequences of such a change, like overlaps. Some packages:

git clone git@github.com:eic/epic.git
git clone git@github.com:eic/irt.git
git clone git@github.com:eic/EDM4eic.git
git clone git@github.com:eic/EICrecon.git

You can also explore how this works with external packages, such as:

git clone https://github.com/AIDASoft/DD4hep.git
git clone https://github.com/eic/EDM4eic

Some repositories have changed capitalization over time, you may need to rename them for build.sh to pick them up. Please report/file an issue/contact the Mattermost helpdesk, if you come across such instances.

Key Points

• Any downloaded ePIC software package can be installed using build.sh