Comment 2 for bug 1650664

Valentin,
Thank you for your response, I understand that this new package has a lot more moving parts.

Your suggestion in part a) seems to be correct, so that issue is solved.

I am concentrating on getting the installation on the Scientific Linux system up and working, so I will concentrate on the issues b) and e) you identified. There are some issues with the version of boost on that system, so I am not attempting to install LHAPDF there.

I started with a clean installation of MG5_aMC_2_5_2. I then did 'install hepmc', which claims it installed correctly. However, after this the command "display options hepmc_path" returns
 hepmc_path : None (user set)

I then set a path via
set hepmc_path /het/p4/mbuckley/MG5_aMC_v2_5_2/HEPTools/hepmc

now the result of "display options hepmc_path" is
hepmc_path : /het/p4/mbuckley/MG5_aMC_v2_5_2/HEPTools/hepmc (user set)

However, I have checked that quitting MG5_aMC and restarting it causes this variable to be unset. This is despite the fact that my input/mg5_configuration.txt file contains the line
hepmc_path = /het/p4/mbuckley/MG5_aMC_v2_5_2/HEPTools/hepmc

Setting this path for hepmc inside the MG5_aMC environment, when I then went to install pythia8 using install pythia8 --with_lhapdf5=OFF --with_lhapdf6=OFF --logging=DEBUG --keep_source I get the following message at the start of installation

|| /!\/!\/!\
|| Note that he following version of HEPMC
|| /cms/base/cmssoft/slc6_amd64_gcc481/cms/cmssw/CMSSW_7_1_0_pre9/external/slc6_amd64_gcc481
|| was detected as *not* supporting named weights. The MG5aMC-PY8 interface will have to write a separate hepmc file
|| for each extra weight potentially specified for studying systematic uncertainties (PDF, scale, merging, etc...)
We recommend that you change to the version of hepmc to the one that can be installed with this tool
|| /!\/!\/!\

I then get the error:
A problem occured during the installation of 'mg5amc_py8_interface'.
Content of the installation log file '/het/p4/mbuckley/MG5_aMC_v2_5_2/HEPTools/MG5aMC_PY8_interface/mg5amc_py8_interface_install.log':

The version of HEPMC2 linked to Pythia8 seems not to include a static library.
This is necessary for the default compilation of MG5aMC_PY8_interface.
You can try again with the option --pythia8_makefile but HEPMC2 will need to be available at runtime.

I am not sure why MadGraph is defaulting to the system's version of hepmc rather than the local one, or why it cannot seem to remember where hepmc is. After this installation command, the pythia8 path is set correctly, so the problem seems just to be with mg5amc_py8_interface_path

Thanks for you help.