Data Analysis

Once the simulation is done, one has to manage huge amounts of data and get the physics out of it. Here we present tools, libraries and related software to analyse simulation data.

• ROOT

  The ROOT system provides a set of OO frameworks with all the functionality needed to handle and analyse large amounts of data in a very efficient way. Having the data defined as a set of objects, specialised storage methods are used to get direct access to the separate attributes of the selected objects, without having to touch the bulk of the data. Included are histograming methods in 1, 2 and 3 dimensions, curve fitting, function evaluation, minimisation, graphics and visualization classes to allow the easy setup of an analysis system that can query and process the data interactively or in batch mode.

  Thanks to the builtin CINT C++ interpreter the command language, the scripting, or macro, language and the programming language are all C++. The interpreter allows for fast prototyping of the macros since it removes the time consuming compile/link cycle. It also provides a good environment to learn C++. If more performance is needed the interactively developed macros can be compiled using a C++ compiler.

  The system has been designed in such a way that it can query its databases in parallel on MPP machines or on clusters of workstations or high-end PC's. ROOT is an open system that can be dynamically extended by linking external libraries. This makes ROOT a premier platform on which to build data acquisition, simulation and data analysis systems.