Transcript What to do with ROOT ?

What is “ROOT” ?
An Open Source Project
Started in 1995
7 full time developers at CERN, plus Fermilab
Large number of part-time developers: let users
participate
Available (incl. source) under GNU LGPL
Nowadays most of HEP community uses it every day
What does ROOT stand for?
it is not an acronym, just a name. The idea is to make a
system that
provides a solid ROOT on which other systems can grow (as
you can see
with Trees, Branches and Leafs we are deep in the fauna
nomenclature -:)).
Also, the name ROOT contains nicely the letters OO of Object
Oriented.
Fons Rademakers / ROOT Project Founder
What does ROOT stand for?
At the start of the project in January 1995, I came quickly to the name
ROOT for our system. The intention to move towards Object Oriented
Technology was already well accepted at this time. It was clear to us
that a basic framework providing at least the services we had in the
past with CERNLIB was necessary before moving higher level applications.
ROOT really means the "roots" for end-users applications.
Once we have the roots well installed in the ground, Trees or other
Flowers can flourish. We hope that we are reaching this stage now.
A possible acronym for the system could be
"Rapid Object-Oriented Technology”
Rene Brun / ROOT Project Founder
ROOT in a Nutshell
Framework for large scale data handling
Provides, among others,
–an efficient data storage, access and query system (PetaBytes)
–advanced statistical analysis algorithms (multi dimensional
histogramming, fitting, minimization and cluster finding)
–scientific visualization: 2D and 3D graphics, Postscript, PDF,
LateX
–geometrical modeller
–PROOF parallel query engine
Things you can do with ROOT
Math Histogramming – Fitting
….1D/2D/3D
Graphics
Data
http://cms.web.cern.ch
Higg discovered.
QGP as well
http://aliceinfo.cern.ch/Public/en/Chapter1/eventdisplays.html
Histogramming
Histogram is just occurrence counting, i.e. how
often they appear
•Example: {1,3,2,6,2,3,4,3,4,3,5}
Random Number Generator
Solution: more complex function
–Mersenne Twister (TRandom3) is recommended generates random
number between >0 and <= 1
–period 106000, fast!
•Flat probability distribution function good for dice, usually not for physics:
–measurement uncertainty: gaussian
–particle lifetime: N(t) = N0 exp(-t/τ) i.e. exponential
–energy loss of particles in matter: landau
Random Number Generators: A Survival Guide for Large Scale
Simulations
http://arxiv.org/abs/0905.4238
DOCUMENTATIONS
ROOT is a framework – only as good as its
documentation.
http://root.cern.ch
•User's Guide (it has your answers!)
•Reference Guide
1.
What is TRandom?
2.
What functions does it have?
Linux Server
ssh <userid>@calc.phys.jyu.fi
Starting ROOT
Uses C++ Interpreter CINT
Starting ROOT
Uses C++ Interpreter CINT
Starting ROOT
Uses C++ Interpreter CINT
http://www.cs.ucr.edu/~weesan/cs183/
What is Unix?
A multi-task and multi-user Operating System
Developed in 1969 at AT&T’s Bell Labs by
Ken Thompson (Unix)
Dennis Ritchie (C)
Douglas Mcllroy (Pipes - Do one thing, do it well)
Some other variants: System V, Solaris, SCO Unix,
SunOS, 4.4BSD, FreeBSD, NetBSD, OpenBSD, BSDI
http://www.cs.ucr.edu/~weesan/cs183/
What is Linux?
A clone of Unix
Developed in 1991 by Linus Torvalds, a Finnish graduate student
Inspired by and replacement of Minix
Linus' Minix became Linux
Consist of
Linux Kernel
GNU (GNU is Not Unix) Software
Software Package management
Others
http://www.linuxdevices.com/files/misc/ibm-watchpad
What is Linix?
Originally developed for
32-bit x86-based PC
Ported to other
architectures, eg.
Alpha, VAX, PowerPC, IBM
S/390, MIPS, IA-64
PS2, TiVo, cellphones,
watches, Nokia N810,
NDS, routers, NAS, GPS, …
http://www.cs.ucr.edu/~weesan/cs183/
Which Linux Distribution is better?
> 300 Linux Distributions
Slackware (one of the oldest, simple and stable distro.)
Redhat
RHEL (commercially support)
Fedora (free)
CentOS (free RHEL, based in England)
SuSe ( based in German)
Gentoo (Source code based)
Debian (one of the few called GNU/Linux)
Ubuntu (based in South Africa)
Knoppix (first LiveCD distro.)
…
http://www.cs.ucr.edu/~weesan/cs183/
Ubuntu
Which Linux Distribution is
better?
Debian
Knoppi
x
Slackware
Gentoo
CentO
S
Redhat
Source:
http://futurist.se/gldt/
Linux Shell

Shell interprets the command and
request service from kernel

Similar to DOS but DOS has only one
set of interface while Linux can select
different shell
ls
whoami
pwd
Bash, Tcsh, Zsh
Kernel
Bourne Again shell (Bash), TC shell
(Tcsh), Z shell (Zsh)



Different shell has similar but different functionality
Bash is the default for Linux
Graphical user interface of Linux is in fact an application
program work on the shell
File management
Directory Tree
(root)
When you log on the the
Linux OS using your
username you are
automatically located in
your home directory.
The most important subdirectories
inside the root directory are:
/bin : Important Linux commands available to the average user.
/boot : The files necessary for the system to boot. Not all Linux
distributions use this one. Fedora does.
/dev : All device drivers. Device drivers are the files that your Linux
system uses to talk to your hardware. For example, there's a file in the
/dev directory for your particular make and model of monitor, and all of
your Linux computer's communications with the monitor go through that
file.
/etc : System configuration files.
/home : Every user except root gets her own folder in here, named for
her login account. So, the user who logs in with linda has the directory
/home/linda, where all of her personal files are kept.
/lib : System libraries. Libraries are just bunches of programming code
that the programs on your system use to get things done.
The most important subdirectories
inside the root directory are:
/mnt : Mount points. When you temporarily load the contents of a CDROM or USB drive, you typically use a special name under /mnt. For
example, many distributions (including Fedora) come, by default, with
the directory /mnt/cdrom, which is where your CD-ROM drive's contents
are made accessible.
/root : The root user's home directory.
/sbin : Essential commands that are only for the system administrator.
/tmp : Temporary files and storage space. Don't put anything in here
that you want to keep. Most Linux distributions (including Fedora) are
set up to delete any file that's been in this directory longer than three
days.
/usr : Programs and data that can be shared across many systems and
don't need to be changed.
/var : Data that changes constantly (log files that contain information
about what's happening on your system, data on its way to the printer,
and so on).
Home directory
You can see what your home directory is called by
entering
pwd (print current working directory)
Commands:
Some of the basic commands you
should learn are the ones that
help you navigate the file system.
/ (root directory)
/root – home directory of the user root
pwd – you can see your home directory
df – to see disk space available
cd – to change to different directory or to go back to home dir
.. - move to parent directory
ls – list the contents of a directory; Options: -l (more info)
-a (displays hidden files)
-t (sort by time)
-r (oldest first)
Example: ls –ltr : display an long list of files that are sorted by time, display the oldest
ones first
cp : copy one file to another
rm : remove a file
man : ask for the manual (or help) of a command
e.g. man cd ask for the manual of the command cd
cat : to show the content of a text file
e.g. cat abc.txt show the content of abc.txt
whoami : to show the username of the current user
Directory is denoted by a / (slash) character
Executable program by a *
Hidden file preceded by a . (dot)
The concept of simple file and
directory is similar to DOS
Names in blue are directories, indicated by a
letter d at the beginning of the line