[Rivet] Pythia+PU+Rivet problem

[Tomasz Fruboes]

Hi,


  please find part of the printout attached below. After inserting 
additionall printouts (and protecting all of my printouts by 
std::cout.flush()) I see, that the  exception occurs after the 
Rivet::AnalysisHandler::analyze() call and before calling the analyze() 
method of my analysis class.

  I have checked - the sumOfWeight counter is not to affected by this 
(ie it's lower than the number of generated events by number of exceptions).

  Cheers,
    Tomasz





                             Event listing (no momenta)

     I  particle/jet  K(I,1)   K(I,2) K(I,3)     K(I,4)      K(I,5)    C 
tag  AC tag

     1  !p+!              21      2212    0           0           0 
    0       0
     2  !p+!              21      2212    0           0           0 
    0       0
     3  !u!               21         2    1           0           0 
    1       0
     4  !ubar!            21        -2    2           0           0 
    0       3
     5  !u!               21         2    3           0           0 
    0       0
     6  !ubar!            21        -2    4           0           0 
    0       0
     7  !g!               21        21    0           0           0 
    0       0
     8  !Z0!              21        23    0           0           0 
    0       0
     9  !mu-!             21        13    8           0           0 
    0       0
    10  !mu+!             21       -13    8           0           0 
    0       0
    11  (Z0)              11        23    8          12          13 
    0       0
    12  mu-                1        13    9           0           0 
    0       0
    13  mu+                1       -13   10           0           0 
    0       0
    14  (ud_1)        A   12      2103    1          63          63 
    0       0
    15  (g)           I   12        21    1          63          63 
    0       0
    16  (g)           I   12        21    2          63          63 
    0       0


On 15.04.2014 10:20, Andy Buckley wrote:
> On 14/04/14 23:17, Tomasz Fruboes wrote:
>> Hi,
>>
>>   thanks for answer. No, the analysis code doesnt access the particle
>> names. I'm getting quite a lot event printouts (not requested :) ), so
>> I'm guessing that rivet is finding something weird with the events and
>> prints it out as a debug info. And time to time, during the printout, he
>> asks for the name of pdg=1...3 resulting with the crash.
>
> Sounds reasonable, but I don't know where in Rivet there would be an
> event printout... can you send a bit of the printout so we can tell if
> it's coming from Rivet or HepMC (or other) code? Strange...
>
> If you put printouts in your code (or some other method), can you tell
> if the exception is being thrown before your code executes, or if it's
> triggered by something that you are calling in the analysis?
>
>>   PU in Pythia6 seems to be easiest to get on generator level (AFAIK in
>> pythia8 this has to be handled on c++ level - by defining two separate
>> pythia sources - and cannot be controlled from "cards" level). BTW the
>> workaround is not intended to be included in any official release (I'm
>> not a developer/maintainer of the rivet wrapper present in CMSSW), this
>> is just to keep going with work. So - do you think this can be dangerous
>> on the rivet side (ie can broke some rivet internals)?
>>
>>   My main concern with the workaround is that event weight counting can
>> get corrupted. I'll try to investigate this (unless you got immediate
>> answer :) )
>
> I think that is possible, yes. And depending on where the error occurs,
> you might be filling some histograms but not others.
>
> Andy
>
>
>
>> On 14.04.2014 22:13, Andy Buckley wrote:
>>> Hi Tomasz,
>>>
>>> I didn't know anyone was using the old PYTHIA pile-up system! Looking in
>>> the Rivet code, that exception is thrown when it tries to find a text
>>> name for an unknown particle: since PIDs 1,2,3 are all quarks and hence
>>> should never be seen in a stable event final state, it leads to your
>>> error.
>>>
>>> Do you know why your code could be trying to access Particles' string
>>> names? It is possible that there's a bug in PYTHIA6 when run this way,
>>> which leads to partons appearing in the final state: I'm not sure.
>>> Obviously it's better not to put catch-all exception handling around the
>>> analyze function call -- you can hide serious problems that way and make
>>> debugging hard for everyone: presumably the error is being thrown by
>>> something inside your analysis routine, so maybe wrap *that* in the try
>>> block (and make the try block as small as possible) rather than the
>>> general CMSSW Rivet wrapper?
>>>
>>> By the way, I strongly recommend updating to use Rivet 1.9.0 -- your
>>> analysis should continue to work as before, but several bugs were fixed
>>> between 1.8.2 and that. All future releases, bugfixes, etc. are in the
>>> Rivet 2.x series.
>>>
>>> Best wishes,
>>> Andy
>>>
>>>
>>> On 14/04/14 16:52, Tomasz Fruboes wrote:
>>>> Dear Experts,
>>>>
>>>>    in our rivet (1.82) analysys I'm trying to include pileup. Pileup is
>>>> added on generator level by pythia6 using following settings:
>>>>
>>>>               'MSTP(131)=1
>>>>               'MSTP(132)=3
>>>>               'MSTP(133)=1
>>>>               'PARP(131)=0.15
>>>>
>>>> Above gives n=10 PU interactions on average. In every 1 out of ~300
>>>> events I'm getting following exception
>>>>
>>>> A std::exception was thrown.
>>>> Particle ID '1' not known.
>>>>
>>>> (where ID can be 2 or 3 as well).
>>>>
>>>> I have added try/catch block in order to handle this (see [1] below).
>>>> Could you comment if this is a safe workaround? Or maybe there is a
>>>> better solution?
>>>>
>>>>    Thank you,
>>>>     Tomasz Fruboes
>>>>
>>>>
>>>> [1] Source code of our rivet wrapper:
>>>>
>>>> https://github.com/cms-sw/cmssw/blob/CMSSW_7_1_X/GeneratorInterface/RivetInterface/plugins/RivetAnalyzer.cc
>>>>
>>>>
>>>>
>>>> Line ~120 was changed to
>>>>     //run the analysis
>>>>     try {
>>>>         _analysisHandler.analyze(*myGenEvent);
>>>>     } catch (...) {
>>>>           std::cout << "Exception caught...\n" ;
>>>>     }
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Rivet mailing list
>>>> Rivet at projects.hepforge.org
>>>> https://www.hepforge.org/lists/listinfo/rivet
>>>
>>>
>>
>
>