10.1. Standard Analysis Packages 577
The installation of ROOT depends on the platform and therefore the user should
read through the installation instructions available on the internet site mentioned
above.
In the following sections we will briefly discuss the basic structure of ROOT and
introduce the reader to its syntax using some examples. For further information the
interested reader is encouraged to look at different manuals available on ROOT’s
internet site. Although all the examples that will follow have been tested only on
an Intel x86 machine running under Fedora Core 1, the codes should work on any
platform.
A.2 Data Handling, Organization, and Storage
ROOT can handle data in various formats. In fact, since it is based on C++, one
can tailor the analysis routine to import/export data in any format.
For organizing and storage, ROOT authors have developed a specific method
calledtrees. The tree structure is designed to optimize the access and storage of
data. A tree consists of branches, buffers, and leaves. The structure is stored in a
special binary format file with an extension.root. The ROOT file is composed of
directories containing objects in several levels. Therefore it looks like a standard
UNIX file directory. The best way to browse a ROOT file is to use theTBrowser
method. This can be done by creating aTBrowserobject on ROOT’s command
line by typingTBrowser b;, which creates a window similar to the one shown in
Fig.10.1.1.
Figure 10.1.1: TBrowser window of ROOT.