Editing ROOT (section)

== Description ==
CERN maintained the [[CERN Program Library]] written in [[FORTRAN]] for many years. Its development and maintenance were discontinued in 2003 in favour of ROOT, which is written in the [[C++]] programming language.
ROOT development was initiated by René Brun and Fons Rademakers in 1994. Some parts are published under the [[GNU Lesser General Public License]] (LGPL) and others are based on [[GNU General Public License]] (GPL) software, and are thus also published under the terms of the GPL. It provides [[platform independent]] access to a computer's graphics subsystem and [[operating system]] using [[Abstraction (computer science)|abstract layers]]. Parts of the abstract platform are: a [[graphical user interface]] and a [[Graphical user interface builder|GUI builder]], container classes, [[Reflection (computer science)|reflection]], a C++ [[Scripting language|script]] and [[command line]] [[Interpreter (computing)|interpreter]] ([[CINT]] in version 5, [[Cling (command line interpreter)|cling]] in version 6), object [[serialization]] and [[Persistence (computer science)|persistence]].

The packages provided by ROOT include those for
* [[Histogram]]ming and [[Graph of a function|graphing]] to view and analyze [[Distribution (mathematics)|distributions]] and [[Function (mathematics)|functions]],
* [[curve fitting]] (regression analysis) and minimization of [[Functional (mathematics)|functionals]],
* [[statistics]] tools used for [[data analysis]],
* [[Matrix (mathematics)|matrix]] algebra,
* [[four-vector]] computations, as used in [[high energy physics]],
* standard [[Function (mathematics)|mathematical functions]],
* [[Multivariate analysis|multivariate data analysis]], e.g. using [[Artificial neural network|neural networks]],
* image manipulation, used, for instance, to analyze [[astronomical]] pictures,
* access to distributed data (in the context of the [[Grid computing|Grid]]),
* [[distributed computing]], to parallelize [[Data analysis|data analyses]],
* [[Persistence (computer science)|persistence]] and [[serialization]] of objects, which can cope with changes in class definitions of persistent data,
* access to [[databases]],
* [[3D computer graphics|3D]] [[Visualization (graphic)|visualizations]] (geometry),
* creating files in various graphics formats, like [[PDF]], [[PostScript]], [[Portable Network Graphics|PNG]], [[Scalable Vector Graphics|SVG]], [[LaTeX]], etc.
* interfacing [[Python (programming language)|Python]] code in both directions,
* interfacing [[Monte Carlo method|Monte Carlo]] [[event generator]]s.

[[File:Atlas_ROOT_plot.png|thumb|The ATLAS experiments presented on 4 July 2012 the status of the Standard Model Higgs search. All the plots presented that day were created in ROOT.]]

A key feature of ROOT is a data container called ''tree'', with its substructures ''branches'' and ''leaves''. A tree can be seen as a sliding window to the raw data, as stored in a file. Data from the next entry in the file can be retrieved by advancing the index in the tree. This avoids memory allocation problems associated with object creation, and allows the tree to act as a lightweight container while handling buffering invisibly.

ROOT is designed for high [[Computer performance|computing efficiency]], as it is required to process data from the [[Large Hadron Collider]]'s experiments estimated at several [[petabyte]]s per year. {{As of|2009}} ROOT is mainly used in [[data analysis]] and [[data acquisition]] in [[particle physics]] (high energy physics) experiments, and most {{As of|2009|alt=current}} experimental plots and results in those subfields are obtained using ROOT.

The inclusion of a C++ interpreter ([[CINT]] until version 5.34, Cling from version 6.00) makes this package very versatile as it can be used in interactive, scripted and compiled modes in a manner similar to commercial products like [[MATLAB]].

On July 4, 2012 the ATLAS and CMS LHC's experiments presented  the status of the Standard Model Higgs search. [https://root.cern/gallery/#higgs-plots All data plotting presented that day used ROOT].