1. ROOT An object oriented HEP analysis framework.

2. Computing in Physics Physics = experimental science =>Experiments (e.g. at CERN) Planning phase Physics simulations (e.g. PYTHIA) (FORTRAN), C++ Detector simulations (e.g. GEANT) (FORTRAN), C++ Design phase Detector, electronics, mechanical design VHDL, Autocad, etc. Prototyping and lab-tests LABVIEW, C/C++

3. Computing in Physics (cont.) Installation phase Data taking Data acquisition C/C++ Online monitoring C++ Detector control C++ Data analysis Event reconstruction C++ Physics analysis C++

4. Physics data types Histogram 1-dim, 2-dim Ntuple Tree Events Vertices Tracks Measurements Particle properties

5. ROOT The ROOT Home: http://root.cern.ch http://root.cern.ch The ROOT Team: Rene Brun & Fons Rademakers

6. ROOT Free

7. Finding Examples The ROOT Tutorials: http://root.cern.ch/root/Tutorials.html http://root.cern.ch/root/Tutorials.html The ROOT How To's: http://root.cern.ch/root/Howto.html http://root.cern.ch/root/Howto.html For on-line help for a particular topic it's very useful to use their facility to search the ROOT site. http://root.cern.ch/roothttp://root.cern.ch/root

8. Class Schedule Overview of the ROOT Framework GUI basics Command line basics Finding Information (class reference guide) Getting started with the exercises

9. ROOT Overview Concepts: Object Oriented Design, Frameworks Services and Utilities Libraries Physical Organization

10. Object Oriented Concepts Members: a “has a” relationship to the class. Inheritance: an “is a” relationship to the class.  Class: the description of a “thing” in the system  Object: instance of a class  Methods: functions for a class

11. ROOT's Services/Utilities  Histogramming and Fitting  Graphics (2D, 3D)  I/O to file or socket: specialized for histograms, Ntuples (Trees)  Collection Classes and Run Time Type Identification User Interface  GUI: Browsers, Panels, Tree Viewer  Command Line interface: C++ interpreter CINT  Script Processor (C++ compiled  C++ interpreted)

12. ROOT's Services/ Utilities

20. The Libraries Over 350 classes Core CINT Libraries loaded at startup: Hist, Tree … Libraries loaded when needed: HistPainter, TreePlayer,… Special purpose libraries: EG, Physics…

21. ROOT’s Class Categories The ROOT framework consists of about 350 C++ classes. Class Categories: 1. Base Classes 2. Container Classes 3. Histograms and Minimization Classes 4. Tree and Ntuple Classes 5. Linear Algebra, Matrix, and Vector Classes

22. ROOT’s Class Categories (cont.) 6. 2D & 3D Graphics Classes 7. GUI Classes 8. Operating System Interface 9. Networking Classes 10. Documentation Class 11. Interactive Interface 12. PROOF Server

23. From Raw Data to a ROOT Tree 1. Raw Data: x1, x2, x3, n=10,000 2. Column wise Ntuple 3. ROOT Tree

24. The Framework Organization

25. Three User Interfaces GUI windows, buttons, menus Root Command line CINT (C++ interpreter) Macros, applications, libraries (C++ compiler and interpreter)

26. GUI Basics Browsing and opening files Drawing histograms Right click, left click, middle click Draw Panel Fit Panel Adding Color and Zooming Adding text and other objects Dividing the canvas Setting the log scale

27. GUI Basics Display the browser TBrowser b; Start root > root Quit root (just in case) root[0]>.q

28. The ROOT file A directory structure like UNIX Items in a directory can be: subdirectory objects (canvas, histograms, etc.) root trees

29. Displaying a Histogram Display a histogram The Canvas Open the root file Browse the file

30. Basic Navigation by Clicking Left Click select the object drag the object resize the object Right Click context menu class::name methods Middle Click activate canvas freezes event status bar

31. The Draw Panel The Event Status The Draw Panel Adding Error bars Slider Defaults

32. Fitting, Coloring, and Zooming Adding a gaussian fit Coloring the histogram Zooming/unzooming

33. Adding Objects to the Canvas The Editor Adding an Arrow Adding Text

34. Adding another Pad Add a Pad Select the new Pad Draw a histogram Add a title for the axis

35. Modifying the Statistics The Canvas in the Browser Setting the (7) statistics options default = 0001111

36. Dividing the Canvas Create a new Canvas Divide it in 2 Draw two histograms. 1. Lego plot 2. LogY