Hi all

(I hope it is the correct category)
For CMS people, have anyone manage to compile packages from CMSSW in SWAN?
I am able to set the environment and run some configurations, but if I download some package, the compilation step fails with this error:

Traceback (most recent call last):
  File "/cvmfs/", line 165, in <module>
    import ROOT
  File "/cvmfs/", line 24, in <module>
    import cppyy
  File "/cvmfs/", line 61, in <module>
    import libPyROOT as _backend
ImportError: /cvmfs/ undefined symbol: _ZNK5TEnum17GetUnderlyingTypeEv
gmake: *** [config/SCRAM/GMake/Makefile.rules:1733: tmp/slc7_amd64_gcc820/src/Analysis/JMEDAS/src/AnalysisJMEDAS/] Error 1
gmake: *** Waiting for unfinished jobs....

I am using 97a Python2 stack, with the other default parameters. If anyone have a working example that I can take a look, that would also very helpful.



I’m not CMS (just SWAN admin :slight_smile: ), but what I see is that the CMSSW stack is using the PyROOT installation of the LCG release stack, which should not happen, since CMSSW comes with its own ROOT installation. So it looks like a problem when setting the CMSSW environment, a conflict with the LCG release stack.

I take the opportunity to say that we are working on making this case (configuring the software stack of an experiment) easier in SWAN, so that users can just select to work with e.g. a given CMSSW stack only, with no LCG release in the environment whatsoever.


1 Like

Hi Enric, all

I dont mean for only CMS people to reply :wink: but I guess we are the only one with this problem.
Just to comment, I found this [1] and [2]. I am not sure if ALL [2] is needed, but I just changed the CMSSW release from [2] with the one I am using, load it before compilation, and now the compilation works.
I am testing other jobs to see if everything works, but it is all good for now. I guess thanks to karolBak!!



Hi @algomez,

We don’t have officially support for it yet, but I can see in the links that you sent, that in the setup they are doing they are using the stack LCG_96. The default one at this moment is LCG_97a with python3.

May you can try that recipes selecting the stack LCG_96 with python 2 when you are starting your session to put it work.


Hi @ozapatam

I tried to use LCG_06 with python 2 but that is not the problem (Also I think CMSSW does not run yet with python3). I think it is something internal in CMSSW that it is trying to load internal lxplus libraries (I believe, I am not sure). So by renaming some of the paths to more centralize libraries, CMSSW is able to compile.

Thanks in any case, and waiting for the “official CMSSW support” in SWAN :slight_smile: