Storing Pythia8 Events In A TTree

I want to run example from Pythia8/rootexamples.I do the above:

make tree

Then, pytree.root is generated:

root pytree.root

And blabla.h+blabla.C are genarated.The problem is that there are no events stored at all!Why this happens?Am I doing something wrong?

Hello again,

My problem is solved.I hadn’t set my environment properly in .bashrc.