How to install Pythia 6 and 8 on your laptop?

• Install Pythia 6 and build the interface to ROOT

Download the file pythia6.tar.gz from the ROOT site ftp://root.cern.ch/root/pythia6.tar.gz and unpack.

tar zxvf pythia6.tar.gz

A directory pythia6/ will be created and some files unpacked into it. Cd into it and compile the Pythia 6 interface to ROOT.

cd pythia6/
./makePythia6.linux

For more information, consult Installing ROOT from Source and skip to the section Pythia Event Generators.

• Install Pythia 8

Download the latest version of Pythia from http://home.thep.lu.se/~torbjorn/Pythia.html and unpack.

tar zxvf pythia8108.tgz

A directory pythia8108/ will be created. Cd into it and follow the instructions in the README file to build Pythia 8. Set the environment variables PYTHIA8 and PYTHIA8DATA (preferably in /etc/profile.d/pythia8.sh):

export PYTHIA8=$HOME/pythia8108
export PYTHIA8DATA=$PYTHIA8/xmldoc

Run configure with the option for shared-library creation turned on.

./configure --enable-shared
make

• Install ROOT from source

Download the source code for ROOT from http://root.cern.ch/ and compile.

tar zxvf root_v5.20.00.source.tar.gz
cd root/
./configure linux --with-pythia6-libdir=$HOME/pythia6 \
  --enable-pythia8 \
  --with-pythia8-incdir=$PYTHIA8/include \
  --with-pythia8-libdir=$PYTHIA8/lib
make
make install

Set the following environment variables (preferably in /etc/profile.d/root.sh):

export ROOTSYS=/usr/local/root
export PATH=$PATH:$ROOTSYS/bin
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ROOTSYS/lib:/usr/local/pythia6
export MANPATH=$MANPATH:$ROOTSYS/man

You should be good to go. Try running the following Pythia 6 and 8 sample macros:

root $ROOTSYS/tutorial/pythia/pythiaExample.C
root $ROOTSYS/tutorial/pythia/pythia8.C