PYTHIA:

to use hepmc:
in Pythia8/pythia8170/examples
source config.csh   (or .sh depending on your shell)
this will add the path to the hepmc version to LD_LIBRARY_PATH


DELPHES:

To setup root
source /lal/root/5.34/setup.csh

to compile DELPHES:
./configure
make

-> other versions of root may work, not garanteed
-> it's not obvious that the gmake clean of Delphes does a proper job



HEPMC:

see the PYTHIA8 README.HepMC file for the installation of hepmc.