1. ROOT Class Day 1 An Object Oriented Data Analysis Framework
September 18
ROOT
An Object Oriented Data Analysis Framework
ROOT was created by Rene Brun and Fons Rademakers in CERN, CINT was created by Masaharu Goto.
The website for this class is at:
www-pat.fnal.gov/root/
The ROOT system website is at:
Day 1
21 September 2018
ROOT Day1
Fons Rademakers

2. The Early ROOT Team 21 September 2018 ROOT Day1 ROOT Class Day 1
Fons Rademakers

3. http://root.cern.ch The ROOT Web Pages General Information and News
Download source and binaries
HowTo’s & tutorials
User Guide & Reference Guide
Roottalk mailing list & Forum
Savannah bug reporting and
21 September 2018
ROOT Day1

4. Acknowledgements Suzanne Panacek (Fermilab) Philippe Canal (Fermilab)
ROOT Class Day 1
September 18
Acknowledgements
Suzanne Panacek (Fermilab)
Philippe Canal (Fermilab)
For their help in developing this course
21 September 2018
ROOT Day1
Fons Rademakers

5. Class Schedule - Day 1 Overview of the ROOT Framework GUI basics
ROOT Class Day 1
September 18
Class Schedule - Day 1
Overview of the ROOT Framework
GUI basics
Command line basics
Finding Information (class reference guide)
Getting started with the exercises
21 September 2018
ROOT Day1
Fons Rademakers

6. Class Schedule - Day 2 ROOT commands and CINT Discuss exercises
ROOT Class Day 1
September 18
Class Schedule - Day 2
ROOT commands and CINT
Discuss exercises
Functions and fitting
Building ROOT Trees
Reading Trees
Using Trees in Analysis
21 September 2018
ROOT Day1
Fons Rademakers

7. Class Schedule - Day 3 Copying Trees Chain of trees
ROOT Class Day 1
September 18
Class Schedule - Day 3
Copying Trees
Chain of trees
Adding your class to ROOT
With the Interpreter
With a compiler (Shared Library)
With ACLiC
Rootcint
ROOT I/O details
Remote I/O
21 September 2018
ROOT Day1
Fons Rademakers

8. ROOT Overview What is ROOT What about PAW
ROOT Class Day 1
September 18
ROOT Overview
What is ROOT
What about PAW
Concepts: Object Oriented Design, Frameworks
Services and Utilities
Libraries
Physical Organization
21 September 2018
ROOT Day1
Fons Rademakers

9. Prehistory In the beginning there was PAW
ROOT Class Day 1
September 18
Prehistory
In the beginning there was PAW
HBOOK
ZEBRA
KUIP
COMIS
SIGMA
Mini/Micro-DST analysis was done using Ntuples
Ntuples are basically simple tables
Only basic types
No data structures
No cross reference between Ntuples
Successful because simple and efficient
Dead-end
No way to grow to more complex data structures
Difficult to extend
Expensive to maintain
Too many languages: Fortran, KUIP, SIGMA
21 September 2018
ROOT Day1
Fons Rademakers

10. Main Goals for New System
ROOT Class Day 1
September 18
Main Goals for New System
Being able to support full data analysis chain
Raw data, DSTs, mini-DSTs, micro-DSTs
Being able to handle complex structures
Complete objects
Object hierarchies
Support at least the PAW data analysis functionality
Histogramming
Fitting
Visualization
Only one language
C++
Better maintainable
Use OOP
Make the system extensible
Use OO framework technology
21 September 2018
ROOT Day1
Fons Rademakers

11. ROOT Class Day 1
September 18
ROOT in a Nutshell
The ROOT system is an Object Oriented framework for large scale data handling applications
Written in C++
Provides, among others,
an efficient data storage and access system designed to support structured data sets (PetaBytes)
a query system to extract data from these data sets
a C++ interpreter
advanced statistical analysis algorithms (multi dimensional histogramming, fitting, minimization and cluster finding)
scientific visualization tools with 2D and 3D graphics
an advanced Graphical User Interface
The user interacts with ROOT via a graphical user interface, the command line or scripts
The command and scripting language is C++, thanks to the embedded CINT C++ interpreter, and large scripts can be compiled and dynamically loaded
21 September 2018
ROOT Day1
Fons Rademakers

12. ROOT: An Open Source Project
ROOT Class Day 1
September 18
ROOT: An Open Source Project
The project is developed as a collaboration between:
Full time developers:
10 people full time at CERN
2 developers at FermiLab
1 developer in Japan (Agilent Technologies)
2 developers at MIT
Large number of part-time contributors
Several thousand users giving feedback, comments, bug fixes and many small contributions
An Open Source Project, source available under the LGPL license
21 September 2018
ROOT Day1
Fons Rademakers

13. ROOT Development Process
ROOT Class Day 1
September 18
ROOT Development Process
We follow an Open Source development model
“Release early, release often”
Major releases 3-4 times per year
Minor releases every 2-3 weeks
Daily/nightly builds + regression testing + benchmarking (rootmarks)
“Let user feedback drive the development”
Bug reporting system
Roottalk mailing list
Annual workshop
Open cvs repository
Let users become developers
21 September 2018
ROOT Day1
Fons Rademakers

14. Object Oriented Concepts
ROOT Class Day 1
September 18
Object Oriented Concepts
Class: the description of a “thing” in the system
Object: instance of a class
Methods: functions for a class
TObject
Members: a “has a” relationship to the class.
Inheritance: an “is a” relationship to the class.
IsA
Event
HasA
HasA
HasA
If you would like to refresh or even learn C++, we have a C++ on-line tutorial available at:
www-pat/fnal/gov/root/CPlusPlus/index.html
Or you can read the chapter "A little C++" in the ROOT User's Guide
Segment
Track
Vertex
HasA
HasA
HasA
Momentum
MeanCharge
MassSquare
21 September 2018
ROOT Day1
Fons Rademakers

15. provides utilities and services
ROOT Class Day 1
September 18
A Framework
provides utilities and services
21 September 2018
ROOT Day1
Fons Rademakers

16. ROOT's Services and Utilities
ROOT Class Day 1
September 18
ROOT's Services and Utilities
Data analysis and visualization tools
Histogramming and Fitting
2D and 3D graphics, Postscript, PDF, LateX
Geometrical modeller
Object persistency and Trees
PROOF parallel query engine
Collection Classes
Run Time Type Identification
Online services
User Interface
GUI: Browsers, Panels, Tree Viewer
Command Line interface: C++ interpreter CINT
Script Processor (C++ compiled  C++ interpreted)
21 September 2018
ROOT Day1
Fons Rademakers

17. Calling API vs Sub-classing API
ROOT Class Day 1
September 18
Calling API vs Sub-classing API
Class
Program using
calling API
Class A
calls
Class Y
method B
virtual method Z
Class
inherits
Class
Class
Class newY
Framework
virtual method Z
Program using
sub-classing API
21 September 2018
ROOT Day1
Fons Rademakers

18. ROOT Library Structure
ROOT Class Day 1
September 18
ROOT Library Structure
ROOT libraries are a layered structure
The CORE classes are always required (support for RTTI, basic I/O and interpreter)
The optional libraries (you load only what you use). Separation between data objects and the high level classes acting on these objects. Example, a batch job uses only the histogram library, no need to link histogram painter library
Shared libraries reduce the application link time
Shared libraries reduce the application size
ROOT shared libraries can be used with other class libraries
Shared libraries are mostly loaded via the plug-in manager
21 September 2018
ROOT Day1
Fons Rademakers

19. The ROOT Libraries Over 1000 classes 1,350,000 lines of code
ROOT Class Day 1
September 18
The ROOT Libraries
Over 1000 classes
1,350,000 lines of code
CORE (12 Mbytes)
CINT (2 Mbytes)
Green libraries linked on demand via plug-in manager (only a subset shown)
21 September 2018
ROOT Day1
Fons Rademakers

20. Three User Interfaces GUI windows, buttons, menus
ROOT Class Day 1
September 18
Three User Interfaces
GUI windows, buttons, menus
Command line CINT (C++ interpreter)
Macros, applications, libraries (C++ compiler and interpreter)
21 September 2018
ROOT Day1
Fons Rademakers

21. Differences from PAW Regular grammar (C++) on command line
ROOT Class Day 1
September 18
Differences from PAW
Regular grammar (C++) on command line
Single language (compiled and interpreted)
Object Oriented (use your class in the interpreter)
Advanced Interactive User Interface
Well Documented code. HTML class descriptions for every class.
Object I/O including Schema Evolution
3-D interfaces with OpenGL and X3D.
Regular grammar (C++) on command line
Single language We have one single language C++ instead of a scripting and restricted language KUIP. The macros can be interpreted or dynamically executed via the compiler
Object Oriented The main point is that from the interpreter one can call functions from the user classes if these classes have been run through rootcint. Because a full object dictionary is available we can do all kinds of things with the objects; All what is called reflection or introspection with Java is available in ROOT. This is an extremely important addition on top of C++. The dictionary is the heart of the system. It is with the dictionary that we can do automatic schema evolution for example or have the automatic context menus.
Interactive User Interface  PAW had also an interactive interface (command line and also a mouse interface). The ROOT interface and the GUI is more advanced than PAW. This interface is user oriented. Picking is automatic in the pad.
Well Documented code. HTML class descriptions for every class. The Root code is better documented than the PAW code. Html documentation for the source is generated automatically and available from the Web. User classes can also be documented automatically via the THtml class.
Object I/O including Schema Evolution I/O in ROOT cannot be compared with PAW I/O. PAW I/O was limited to simple histograms or ntuples. ROOT can be used as the main I/O engine for user classes including automatic schema evolution.
Root supports network classes (TCP/IP sockets, remote I/O via rootd)
21 September 2018
ROOT Day1
Fons Rademakers

22. PAW to ROOT File Conversion
ROOT Class Day 1
September 18
PAW to ROOT File Conversion
Get the example PAW file from ftp://root.cern.ch/root/exercises.tar.gz
exercises_files/day1/toyz.rz
At the system prompt type
> h2root toyz.rz toyz.root
Once you've done the conversion, you can then start a ROOT session and open toyz.root
Also see:
21 September 2018
ROOT Day1
Fons Rademakers

23. A Data Analysis & Visualization Tools
ROOT Class Day 1
September 18
A Data Analysis & Visualization Tools
21 September 2018
ROOT Day1
Fons Rademakers

24. Graphics: 1,2,3-D functions
ROOT Class Day 1
September 18
Graphics: 1,2,3-D functions
21 September 2018
ROOT Day1
Fons Rademakers

25. Histograms 21 September 2018 ROOT Day1 ROOT Class Day 1 September 18
Fons Rademakers

26. Full LateX support on screen and postscript
ROOT Class Day 1
September 18
Full LateX support on screen and postscript
Formula or
diagrams can be
edited with the mouse
TCurlyArc
TCurlyLine
TWavyLine
and other building blocks for Feynman diagrams
21 September 2018
ROOT Day1
Fons Rademakers

27. Alice 3 million nodes 21 September 2018 ROOT Day1 ROOT Class Day 1
Fons Rademakers

28. ROOT Overview Summary Concepts: Object Oriented Design, Frameworks
ROOT Class Day 1
September 18
ROOT Overview Summary
Concepts: Object Oriented Design, Frameworks
Services and Utilities
Libraries
Physical Organization
PAW Compatibility
Some Visual Examples
21 September 2018
ROOT Day1
Fons Rademakers

29. GUI Basics Browsing and opening files Drawing histograms
ROOT Class Day 1
September 18
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
21 September 2018
ROOT Day1
Fons Rademakers

30. GUI Basics Start root Quit root (just in case) Display the browser
ROOT Class Day 1
September 18
GUI Basics
Start root
> root
Quit root (just in case)
root[0] .q
Display the browser
TBrowser b;
Step by Step:
Start ROOT
> root
Quit Root
root[0]> .q
Start Root again and create a browser object. The constructor of the browser will automatically draw the browser
root[0]> TBrowser b;
21 September 2018
ROOT Day1
Fons Rademakers

31. Displaying a Histogram
ROOT Class Day 1
September 18
Displaying a Histogram
Open the ROOT file
Browse the file
Display a histogram The Canvas
Step by Step:
1. select the Open menu item from the File menu
2. select “Example.root” and click on Open
3. Select the Refresh menu item in the View menu
4. Double click on Example.root
5. double click on myTree
6. double click on the xs1
21 September 2018
ROOT Day1
Fons Rademakers

32. Basic Navigation by Clicking
ROOT Class Day 1
September 18
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
pop pads
freezes event status bar
Step by Step
To bring up the context menu
Right Click on the object
To drag an object
Left Click, hold, and drag the mouse
To select an object
Left Click and hold
To resize an object
Place mouse over object border
Left Click
Drag the mouse
To create a new canvas and activate a canvas
Select the New Canvas item in the File menu on the c1 canvas
Use the middle mouse button to activate the old canvas c1
Use the middle mouse button to activate the new canvas c1_n2
Note the colored frame around the canvas that is active
21 September 2018
ROOT Day1
Fons Rademakers

33. The Editor Panel The Event Status The Editor Panel Adding Error bars
ROOT Class Day 1
September 18
The Editor Panel
The Event Status
The Editor Panel
Adding Error bars
Changing colors
Styles
Step by Step
To show the Event Status bar:
- Select the Event Status menu item in the Options menu.
- The Event Status bar shows the title of the selected object , the name, the coordinate in pixels, and other object specific information.
To bring up the Draw Panel for the histogram
- Select the horizontal part of the histogram
- Right click to get the context menu
- Select the Draw Panel
To draw the error bars
- On the Draw Panel select “E1:errors/edges” and “Same Picture”
- Click Draw
To zoom the histogram
- select the left edge of the slider (the gray bar at the bottom)
- drag it to the right, this moves the left edge of the histogram
- do the same with the right side
- select the slider and move it left or right to move the range
To return to the defaults
- On the Draw Panel select Defaults
21 September 2018
ROOT Day1
Fons Rademakers

34. The Editor Panel Sliders Rebining 21 September 2018 ROOT Day1
ROOT Class Day 1
September 18
The Editor Panel
Sliders
Rebining
Step by Step
To show the Event Status bar:
- Select the Event Status menu item in the Options menu.
- The Event Status bar shows the title of the selected object , the name, the coordinate in pixels, and other object specific information.
To bring up the Draw Panel for the histogram
- Select the horizontal part of the histogram
- Right click to get the context menu
- Select the Draw Panel
To draw the error bars
- On the Draw Panel select “E1:errors/edges” and “Same Picture”
- Click Draw
To zoom the histogram
- select the left edge of the slider (the gray bar at the bottom)
- drag it to the right, this moves the left edge of the histogram
- do the same with the right side
- select the slider and move it left or right to move the range
To return to the defaults
- On the Draw Panel select Defaults
21 September 2018
ROOT Day1
Fons Rademakers

35. Fitting, Coloring, and Zooming
ROOT Class Day 1
September 18
Fitting, Coloring, and Zooming
Adding a gaussian fit
Coloring the histogram
Zooming/unzooming
Step by Step
To add a gaussian fit:
- Select the horizontal part of the histogram outline
- Right click to get the context menu
- Select the Fit Panel
- Select “gaus” and “Same Picture”
- Select Fit
To add color and fill
- Select the horizontal part of the histogram
- Select the “SetFillAttributes”
- Select a color and your favorite pattern
- Select Apply
To zoom the X-Axis
- Left click on the left axis point (the cursor changes to a hand)
- Drag the mouse to the right axis point
- Release
To un zoom:
- Right click on the X-axis. This brings up the context menu for the X axis.
- Select unzoom from the context menu.
21 September 2018
ROOT Day1
Fons Rademakers

36. Adding Objects to the Canvas
ROOT Class Day 1
September 18
Adding Objects to the Canvas
The Editor
Adding an Arrow
Adding Text
Step by Step
To add an Arrow
- Select the Editor menu item from the Edit menu, this brings up the Editor pallet
- Select the Arrow
- Place the mouse on the canvas where you want the arrow to begin and left click and hold
- Drag the mouse to where you want the arrow to end. Release. Now you should see an arrow.
To add Text
- From the Editor palette select the Text/Latex button
- Place the mouse on the canvas where you want the text to begin and left click.
- Type your text and type “Enter”.
- now you should have text displayed on the canvas
To delete an object
- Bring up the context menu by right clicking
- Select Delete
21 September 2018
ROOT Day1
Fons Rademakers

37. Adding Another Pad Add a Pad Select the new Pad Draw a histogram
ROOT Class Day 1
September 18
Adding Another Pad
Add a Pad
Select the new Pad
Draw a histogram
Add a title for the axis
Step by Step
To add a Pad and draw a histogram in it
- Select the Editor menu item from the Edit menu, this brings up the Editor. If you have the Editor already open just click on it to bring it into the foreground
- Select the Pad from the Editor
- Left Click and hold on the canvas where you want the upper left corner of the new Pad to be.
- Drag until the outline fits the size you want for the new Pad
- Make the new pad the active one by clicking on it with the middle mouse button
- Go to your browser and double click on xmain.
- Check your canvas and you should see a histogram in your new Pad.
To add a title to the axis:
- Right click on the axis (x or y) to display the context menu
- Select SetTitle from the context menu.
- Type the string you want to appear on the axis. In this example “X-Axis”
- To center the title, right click on the axis to display the context menu.
- Select CenterTitle. The dialog shows the value kTrue, click OK.
21 September 2018
ROOT Day1
Fons Rademakers

38. Modifying the Statistics
ROOT Class Day 1
September 18
Modifying the Statistics
The Canvas in the Browser
Setting the (7) statistics options
default =
Step by Step
To set the statistics options from the browser
- Bring the Browser window to the foreground by clicking on it
- Double click on the Canvases directory in the left panel
- Click on c1 to display the object that are on the c1 canvas
- Right click on “stats” to bring up the context menu for the statistics panel
- Select SetOptStat. This brings up a new dialog called “TPaveStats::SetOptStat”
- Enter “111111” in the text field in the dialog
- Select OK
Bring the canvas c1 to the foreground by clicking on it to see the new statistics.
The mode has up to seven digits that can be set to on (1) or off (0). Mode = iourmen (default = )
·         n = 1 the name of histogram is printed
·         e = 1 the number of entries printed
·         m = 1 the mean value printed
·         r = 1 the root mean square printed
·         u = 1 the number of underflows printed
·         o = 1 the number of overflows printed
·         i = 1 the integral of bins printed
When trailing digits is left out, they are assumed 0
21 September 2018
ROOT Day1
Fons Rademakers

39. Dividing the Canvas Draw two histograms. Create a new Canvas
ROOT Class Day 1
September 18
Dividing the Canvas
Create a new Canvas
Divide it in 2
Draw two histograms.
1. Lego plot
2. LogY
Step by Step
To create a new canvas:
On the Browser, select the File menu and New Canvas.
To divide the canvas in two
Right click on the new canvas. This will bring up the context menu.
Select Divide from the context menu. This brings up the divide dialog.
Enter 2 for the nx parameter and leave 1 for the ny parameter. These are the first two text fields in the dialog.
To display the left histogram
Activate the left canvas by middle clicking on it.
Display the same histogram and select the Draw Panel for it.
On the Draw panel select lego1 and Draw.
To display the right histogram
Activate the right canvas by middle clicking on it.
Display the same histogram.
Right click on lower right canvas. The context menu should say TPad::c1_2.
Select the SetLogy item.
21 September 2018
ROOT Day1
Fons Rademakers

40. 1-D Drawing Options Any object in the canvas is clickable and editable
ROOT Class Day 1
September 18
1-D Drawing Options
Any object in the canvas
is clickable and editable
21 September 2018
ROOT Day1
Fons Rademakers

41. 2-D Drawing Options 21 September 2018 ROOT Day1 ROOT Class Day 1
Fons Rademakers

42. 2-D Drawing Options 21 September 2018 ROOT Day1 ROOT Class Day 1
Fons Rademakers

43. All these plots can be rotated with the mouse
ROOT Class Day 1
September 18
2-D Drawing Options
All these plots can be rotated with the mouse
21 September 2018
ROOT Day1
Fons Rademakers

44. 2-D Drawing Options Same output on the screen and with
ROOT Class Day 1
September 18
2-D Drawing Options
Same output
on the screen and with
vector Postscript
21 September 2018
ROOT Day1
Fons Rademakers

45. THStack Examples 21 September 2018 ROOT Day1 ROOT Class Day 1
Fons Rademakers

46. Filling with String Variables
ROOT Class Day 1
September 18
Filling with String Variables
21 September 2018
ROOT Day1
Fons Rademakers

47. Command Line Basics Use up and down arrows to recall commands
ROOT Class Day 1
September 18
Command Line Basics
Use up and down arrows to recall commands
$HOME/.root_hist
Use emacs commands to navigate
21 September 2018
ROOT Day1
Fons Rademakers

48. Open a File Open a file for reading Look at the contents of the file
ROOT Class Day 1
September 18
Open a File
Open a file for reading
root [] TFile f("Example.root")
Look at the contents of the file
root [] f.ls()
TFile** Example.root ROOT file
TFile* Example.root ROOT file
KEY: TTree myTree; Example ROOT tree
KEY: TH1F totalHistogram; Total Distribution
KEY: TH1F mainHistogram;1 Main Contributor
KEY: TH1F s1Histogram;1 First Signal
KEY: TH1F s2Histogram;1 Second Signal
21 September 2018
ROOT Day1
Fons Rademakers

49. Plotting a Variable Plot a variable Where did myTree come from?
ROOT Class Day 1
September 18
Plotting a Variable
Plot a variable
root [] myTree->Draw("xs1")
Where did myTree come from?
ROOT executed an implicit gROOT->FindObject("myTree")
And now..
root[] f.ls()
… OBJ: TTree myTree Example ROOT tree: 0 KEY: TTree myTree;1 Example ROOT tree
21 September 2018
ROOT Day1
Fons Rademakers

50. The ROOT File A TFile is a directory structure like UNIX
ROOT Class Day 1
September 18
The ROOT File
This picture shows a TFile with five objects in the top directory (kObjA;1, kObjA;2, kObjB;1, kObjC;1 and kObjD;1). ObjA is on file twice with two different cycle numbers. It also shows four objects in memory (mObjE, mObjeF, mObjM, mObjL). It also shows several subdirectories.
A TFile is a directory structure like UNIX
Object in Memory (OBJ) Object on Disk (KEY)
21 September 2018
ROOT Day1
Fons Rademakers

51. The ROOT Tree Stores large quantities of same class objects:
ROOT Class Day 1
September 18
The ROOT Tree
Stores large quantities of same class objects:
Optimize disk space
Optimize access speed
Had analysis methods (TTree::Draw())
TNtuple is a TTree limited to floating point numbers.
More details later …
Why use Trees
We can use an example to illustrate the difference in saving individual objects vs. filling and saving the tree. Let's assume we have one million events and we write each one to a file, not using a tree. The TFile, being unaware that an event is always an event and the header information is always the same, will contain one million copies of the header. This header is about 60 bytes long, and contains information about the class, such as its name and title. For one million events, we would have 60,000,000 bytes of redundant information. For this reason, ROOT gives us the TTree class. A TTree is smart enough not to duplicate the object header, and is able to reduce the header information to about four bytes per object.
21 September 2018
ROOT Day1
Fons Rademakers

52. Fitting To add a Gaussian Fit Where did htemp come from?
ROOT Class Day 1
September 18
Fitting
To add a Gaussian Fit
root [] htemp->Fit("gaus")
Where did htemp come from?
automatically generated histogram by the TTree::Draw() command.
21 September 2018
ROOT Day1
Fons Rademakers

53. Color and Error Bars To add color Drawing Error Bars Many Draw Options
ROOT Class Day 1
September 18
Color and Error Bars
To add color
root [] htemp->SetFillColor(9)
See pg. 134 of the Users Guide for color index
Or in any Canvas choose View:Colors
Drawing Error Bars
root[] htemp->Draw("E1,same")
Many Draw Options
See the User's Guide
21 September 2018
ROOT Day1
Fons Rademakers

54. Command Line Basics Open and browse a file Drawing histograms
ROOT Class Day 1
September 18
Command Line Basics
Open and browse a file
Drawing histograms
Adding a Fit
Adding Error bars
Adding Color
21 September 2018
ROOT Day1
Fons Rademakers

55. Class Reference Guide Find the class in the index, for example TH1.
ROOT Class Day 1
September 18
Class Reference Guide
Find the class in the index, for example TH1.
Class Inheritance
class TH1 : public TNamed, public TAttLine, public TAttFill, public TAttMarker
Class Description
Private members
Public methods
Code
21 September 2018
ROOT Day1
Fons Rademakers

56. ROOT Class Day 1
September 18
Finding Examples
The ROOT Tutorials:
The ROOT How To's:
For on-line help for a particular topic it's very useful to use their facility to search the ROOT site.
21 September 2018
ROOT Day1
Fons Rademakers

57. Summary Overview of ROOT GUI Basics Command line basics
ROOT Class Day 1
September 18
Summary
Overview of ROOT
GUI Basics
Command line basics
Using the Class reference guide
PAW to ROOT conversion
21 September 2018
ROOT Day1
Fons Rademakers

58. Exercise Overview Session A Session B Use ROOT command line
ROOT Class Day 1
September 18
Exercise Overview
Session A
Use ROOT command line
Write a named and un-named script
Use the GUI to create objects and change their attributes
Save your canvas to a PostScript file
Fit a graph
Session B
Fit and rotate a histogram
Use the Object Browser and the Tree Viewer
Make a profile and contour graphs
Build an event list from a cut
Fill a histograms with random numbers
Use ACLiC
21 September 2018
ROOT Day1
Fons Rademakers

59. Exercise Session C Session C:
ROOT Class Day 1
September 18
Exercise Session C
Session C:
Study an example analysis from H1 at DESY
Learn about the TTree::MakeSelector() method to automatically create a class that loops over each entry in a tree.
Save and retrieve a canvas to and from a ROOT file
Compute the integral of a histogram
Compute the integral of a function within a range
21 September 2018
ROOT Day1
Fons Rademakers

60. Installing ROOT
Go to ROOT web page and download the latest version of ROOT
Install according to description
Set shell variables ROOTSYS, LD_LIBRARY_PATH and PATH
Make sure you can do:
root
root [0] .q
21 September 2018
ROOT Day1

61. Getting Started with the Exercises
ROOT Class Day 1
September 18
Getting Started with the Exercises
Find the exercises on line at:
ftp://root.cern.ch/root/exercises.tar.gz
Today Session A.
21 September 2018
ROOT Day1
Fons Rademakers