Hi, as the error says, you need to have ROOT installed and Pythia’s build system needs to be able to find it, or you will not be able to compile that example. Please make sure that ROOTSYS is set to the correct path and run source $ROOTSYS/bin/thisroot.sh prior to building Pythia. If you still get an error, please report it to the Pythia developers. Cheers,
Thanks for the reply. I have ROOT installed and Pythia’s build system and is working well (I think so), because I can to run the example pythia8.C: using the command root -l pythia8.C
I check the source $ROOTSYS/bin/thisroot.sh
In my bashrc :
#new version root 6:
source /opt/root6/bin/thisroot.sh
#Pythia Env. Variables
export PYTHIA8=/home/andre/Documents/pythia_root/pythia8
export PYTHIA8DATA=$PYTHIA8/xmldoc
#end of My variables
Now I understand(Thanks to Philip Ilten) what is wrong, In the configure of the pythia is missing to put :
--with-root=/path_to_installed_root
--------------------------------------------------
| PYTHIA Configuration Summary
--------------------------------------------------
Configured for LINUX with the following options:
--enable-shared
The following optional external packages will be used:
* HEPMC2
* ROOT