Analysis Software Tutorial

Last update: 13 Jun 2019 [History] [Edit]

This hands-on tutorial will lead you through some typical analysis tools used for doing an xAOD analysis in either the EventLoop or the Athena frameworks, with the cmake build system. Please also note that there is additional documentation for xAOD analysis in the Athena framework as documented here.

For actually working through the tutorial you will find a table of contents on the left, which links to individual pages for the various topics. The first parts of the tutorial cover the basics and are meant to be done in order, and as such work through one page at a time. Some parts will be marked as optional or advanced and you can/should skip those the first time you are working through the tutorial, but the rest should be done in order or you may experience issues. Some of the later sections only cover advanced topics, so you can do them in any order you like. We will tell you once you get to those sections.

If anything is marked as optional or advanced in this tutorial it is mostly included for future reference, typically because it is closely related to the material presented (or because it is an alternate way of doing the same thing). The best way to work through the tutorial is to work through the base material first, and then go back to the optional/advanced sections of interest. Some of them can take you on quite a tangent to the main course of the tutorial, or in the worst case may not be compatible with other parts of the tutorial.

The previous (release 20.7/2.4, RootCore based) version of this tutorial is available here

Using atlassoftwaredocs

This tutorial is the first time we use the new atlassoftwaredocs format instead of the old TWiki pages. Besides being visually more appealing (hopefully), this means that the tutorial is also visible to Google search and has a number of technical advantages. However, it is still quite new, so if you have any feedback on whether you like the format or encounter technical issues, please let us know.

Unfortunately editing the pages is not as simple as for TWiki pages, i.e. you can’t just click an edit button and change the page, but on the plus side you can preview and edit the pages completely on your local machine and the pages are now under git version control. If you want to contribute you can find the instructions for it here

Getting Help

If you have questions about this tutorial or doing analysis on an xAOD please post your questions to the following mailing list: atlas-sw-analysis-forum@cern.ch

Sometimes it is best to browse the code to figure out what’s going on. There are two places I find useful to search for code:

  • LXR which allows you to browse code which is in some official Athena version. This can be useful as most (all?) of the CP tools are dual-use, meaning they exist in Athena-land too.

  • git browser from which you can navigate through the packages to find the code of interest.

  • Later on you’ll learn how to check out the git repository locally. Once you have done that, you will be able to browse it like any other file on your computer.