INFO: No version of lhapdf. Can not run systematics computation

Asked by Aya Ismail Hosny Beshr on 2020-10-10

Hi,

I have recently installed MG5_aMC_v2_8_0 on ubuntu 20.04. When I run the command "install pythia8" in MG session, it starts installing other packages as lhapdf6, boost. The installation ended successfully, but when I generate any process, it gives the following error massage:

INFO: No version of lhapdf. Can not run systematics computation

I don't know why is this happening despite the installation of lhapdf6. I know this error is due to the non linkage between pythia8 and lhapdf. I looked at pythia8_install_log, in the configuration step it specify the path of lhapdf as lhapdf6=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/lhapdf6, but I found that the directory lhapdf6 (at the end of the path) has different name (lhapdf6_py3) in which information for lhapdf installation we stored during pythia installation.

I tried to install pythia8 out of MG with same version used by MG, I specify the following packages during configuration and also you can kindly see the output:

./configure --with-hepmc2=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/hepmc --with-hepmc2-include=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/hepmc/include --with-gzip=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/zlib --with-lhapdf6=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/lhapdf6_py3 --with-lhapdf6-plugin=LHAPDF6.h --with-boost=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/boost --cxx-common='-ldl -fPIC -lstdc++ -DHEPMC2HACK'

Running PYTHIA configuration script. Now is 10 Oct, 2020 EET 06:28:08 am
WARNING: Ignoring invalid option "--with-lhapdf6-plugin".
WARNING: setting default C++ compiler CXX=g++ (CXX environment variable not set)
---------------------------------------------------------------------
| PYTHIA Configuration Summary |
---------------------------------------------------------------------
  Architecture = LINUX
  C++ Compiler CXX = g++
  C++ Flags CXX_COMMON = -ldl -fPIC -lstdc++ -DHEPMC2HACK
  C++ Flags (.so) CXX_SHARED = -shared
  Further options =

The following optional external packages will be used:
 + HEPMC2 (in /home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/hepmc/lib)
 + LHAPDF6 (in /home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/lhapdf6_py3/lib)
 + GZIP
 + BOOST (in /home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/boost/lib)

I have deleted the pythia installation in MG and added the path of the new pythia8 installation to mg5_configuration.txt, I ran any process again and the same error appeared?!!

So, how could I solve this?

Thanks a lot for your time,

Aya

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Olivier Mattelaer
Solved:
2020-10-12
Last query:
2020-10-12
Last reply:
2020-10-12

This question was reopened

Ubuntu20 has some issue with LD_LIBRARY_PATH which can not be update by python.
Did you set those variable in your .bashrc to point to the correct path?

Cheers,

Olivier

> On 10 Oct 2020, at 06:55, Aya Ismail Hosny Beshr <email address hidden> wrote:
>
> New question #693387 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/693387
>
> Hi,
>
> I have recently installed MG5_aMC_v2_8_0 on ubuntu 20.04. When I run the command "install pythia8" in MG session, it starts installing other packages as lhapdf6, boost. The installation ended successfully, but when I generate any process, it gives the following error massage:
>
> INFO: No version of lhapdf. Can not run systematics computation
>
> I don't know why is this happening despite the installation of lhapdf6. I know this error is due to the non linkage between pythia8 and lhapdf. I looked at pythia8_install_log, in the configuration step it specify the path of lhapdf as lhapdf6=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/lhapdf6, but I found that the directory lhapdf6 (at the end of the path) has different name (lhapdf6_py3) in which information for lhapdf installation we stored during pythia installation.
>
> I tried to install pythia8 out of MG with same version used by MG, I specify the following packages during configuration and also you can kindly see the output:
>
> ./configure --with-hepmc2=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/hepmc --with-hepmc2-include=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/hepmc/include --with-gzip=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/zlib --with-lhapdf6=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/lhapdf6_py3 --with-lhapdf6-plugin=LHAPDF6.h --with-boost=/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/boost --cxx-common='-ldl -fPIC -lstdc++ -DHEPMC2HACK'
>
> Running PYTHIA configuration script. Now is 10 Oct, 2020 EET 06:28:08 am
> WARNING: Ignoring invalid option "--with-lhapdf6-plugin".
> WARNING: setting default C++ compiler CXX=g++ (CXX environment variable not set)
> ---------------------------------------------------------------------
> | PYTHIA Configuration Summary |
> ---------------------------------------------------------------------
> Architecture = LINUX
> C++ Compiler CXX = g++
> C++ Flags CXX_COMMON = -ldl -fPIC -lstdc++ -DHEPMC2HACK
> C++ Flags (.so) CXX_SHARED = -shared
> Further options =
>
> The following optional external packages will be used:
> + HEPMC2 (in /home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/hepmc/lib)
> + LHAPDF6 (in /home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/lhapdf6_py3/lib)
> + GZIP
> + BOOST (in /home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/boost/lib)
>
> I have deleted the pythia installation in MG and added the path of the new pythia8 installation to mg5_configuration.txt, I ran any process again and the same error appeared?!!
>
> So, how could I solve this?
>
> Thanks a lot for your time,
>
> Aya
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Aya Ismail Hosny Beshr (ayaa) said : #2

Thanks for your kind reply!

Yes, I have specified them as:

 PATH=$PATH:/home/aya/mg5/MG5_aMC_v2_8_0//HEPTools/lhapdf6_py3/bin
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/aya/mg5/MG5_aMC_v2_8_0/HEPTools/lhapdf6_py3/lib

 Best,

Aya

Aya Ismail Hosny Beshr (ayaa) said : #3

but, there is something strange when I looked at the lhapdf6 directory, there is no bin directory!

Aya Ismail Hosny Beshr (ayaa) said : #4

Hi Olivier,

Is there any way to fix this issue for ?
>Ubuntu20 has some issue with LD_LIBRARY_PATH which can not be update by python.

bec. I have reinstalled MG from the beginning with the following packages (hepmc, zlib, boost). I then installed pythia8244, lhapdf6.2.3 (which uses python 2.7) externally and specify there paths in mg5_configuration.txt and also the following environmental variables in .bashrc :

export PATH=$PATH:/home/aya/lhapdf6.2.3/install/bin/
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/aya/lhapdf6.2.3/install/lib/

I tried again to generate any process, the error (No version of lhapdf. Can not run systematics computation) disappeared, but gives a new error despite defining everything?

Failed to access python version of LHAPDF: If the python interface to LHAPDF is available on your system, try adding its location to the PYTHONPATH environment variable and theLHAPDF library location to LD_LIBRARY_PATH (linux) or DYLD_LIBRARY_PATH (mac os x).The required LD_LIBRARY_PATH is /home/aya/lhapdf6.2.3/install/lib
INFO: can not run systematics since can not link python to lhapdf

I redifned the variable PYTHONPATH as,

PYTHONPATH=/home/aya/lhapdf6.2.3/install/lib/python2.7

Should I change to ubuntu 19 ?

Thanks in advance,

Aya

Hi,

> lhapdf6.2.3 (which uses python 2.7)

That's your issue here, since version 2.8.0 of MG5aMC is using "python3" executable and not "python" executable.
If you have install lhapdf for python2.7, MG5aMC running with python3 will not be able to link to lhapdf compiled for version2.

This is why we have lhapdf_py3 and lhapdf_py2 options such that you can specify one version of lhapdf compatible with python2 and one compatible with python3.

So in your case using
python27 ./bin/mg5_aMC
will force MG5aMC to use python2 and then your lhapdf version will be compatible and this will allow to compute systematics.

Cheers,

Olivier

Aya Ismail Hosny Beshr (ayaa) said : #6

Hi Olivier,

Thanks a lot for your suggestion! I did it and the systematics are running now without any problem!

Aya