[Rivet] unusual segfault:11 while getting a simple jet projection

[Raghav Kunnawalkam Elayavalli]

Hi David, 

Yeah i you are correct :) it was the veto event that fixed it. I missed that i added that in the beginning when i responded rather too quickly. 

Cheers
Raghav

> On May 12, 2016, at 11:37 AM, David Grellscheid <david.grellscheid at durham.ac.uk> wrote:
> 
> Hi Raghav,
> 
> I'm not convinced the problem isn't just hidden. Your two versions are functionally the same. Can you send me the analysis and a _short_ :) HepMC file that fails?
> 
> Thanks,
> 
>  David
> 
> On 12/05/2016 11:01, Raghav Kunnawalkam Elayavalli wrote:
>> Hi Holger,
>> 
>> I just realized what i was doing. The veto wasnt the issue since it did print the correct jet pT. due to the type cast of the fastjet vs jets i think.
>> I needed to have
>>       const FastJets& Ajets = applyProjection<FastJets>(event, "Jets");
>>       const Jets ajets = Ajets.jetsByPt(30*GeV);
>> instead of
>>       Jets ajets = applyProjection<FastJets>(event, "Jets").jetsByPt(30*GeV);
>> 
>> So now it does what its supposed to do.
>> 
>> Cheers,
>> Raghav
>> 
>> 
>> On May 12, 2016, at 10:53 AM, Holger Schulz <holger.schulz at durham.ac.uk<mailto:holger.schulz at durham.ac.uk>> wrote:
>> 
>> 
>> Hi Raghav,
>> 
>> 
>> Looks like you don't have a jet, i.e. ajet.size() might be 0 and
>> by explicitly accessing ajets[0] the segafault seems to come in.
>> 
>> Could you try a
>> if (ajets.size()==0) vetoEvent;
>> 
>> just before the cout?
>> 
>> Holger
>> 
>> 
>> On 12/05/16 09:21, Raghav Kunnawalkam Elayavalli wrote:
>> Hi Rivet Experts,
>> 
>> Im seeing a very weird seg fault when i get the jet projection. I attached the analysis code below in [1] and the error message in [2]. I cant for the life of me figure out what is causing this seg fault when i have other (much more complicated) analysis which use the exact same setup and those work fine.
>> 
>> Cheers
>> Raghav
>> 
>> [1] simple code:
>> // -*- C++ -*-
>> #include "Rivet/Analysis.hh"
>> #include "Rivet/Projections/FinalState.hh"
>> #include "Rivet/Projections/FastJets.hh"
>> 
>> namespace Rivet {
>> 
>>   class JEWEL_test : public Analysis {
>>   public:
>> 
>>     JEWEL_test()
>>       : Analysis("JEWEL_test")
>>     {    }
>> 
>>     void init() {
>>       FinalState fs(-5.0, 5.0, 0.150*GeV);
>>       addProjection(fs, "FS");
>>       addProjection(FastJets(fs, FastJets::ANTIKT, 0.4), "Jets");
>>       _h_njets = bookHisto1D("njets", 10, 0, 10);
>>     }
>> 
>>     void analyze(const Event& event) {
>>       const double weight = event.weight();
>>       Jets ajets = applyProjection<FastJets>(event, "Jets").jetsByPt(30*GeV);
>>       std::cout<<"ajets leading jet pT = "<<ajets[0].pT()<<std::endl;
>>       _h_njets->fill(ajets.size(), weight);
>>     }
>> 
>>     void finalize() {
>>       scale(_h_njets, crossSection()/picobarn/sumOfWeights());
>>     }
>>   private:
>>     Histo1DPtr _h_njets;
>>   };
>> 
>>   DECLARE_RIVET_PLUGIN(JEWEL_test);
>> }
>> 
>> [2]: Error message:
>> pb-d-128-141-166-103:ANALYSIS raghav$ rivet -a JEWEL_test ../out.hepmc
>> Rivet 2.4.1 running on machine pb-d-128-141-166-103.cern.ch<http://pb-d-128-141-166-103.cern.ch/> (x86_64) at 2016-05-12 10:17:31
>> Rivet.Analysis.Handler: WARN  Analysis 'JEWEL_test' is unvalidated: be careful, it may be broken!
>> Reading events from '../out.hepmc'
>> #--------------------------------------------------------------------------
>> #                         FastJet release 3.2.0
>> #                 M. Cacciari, G.P. Salam and G. Soyez
>> #     A software package for jet finding and analysis at colliders
>> #                           http://fastjet.fr<http://fastjet.fr/>
>> #
>> # Please cite EPJC72(2012)1896 [arXiv:1111.6097] if you use this package
>> # for scientific work and optionally PLB641(2006)57 [hep-ph/0512210].
>> #
>> # FastJet is provided without warranty under the terms of the GNU GPLv2.
>> # It uses T. Chan's closest pair algorithm, S. Fortune's Voronoi code
>> # and 3rd party plugin jet algorithms. See COPYING file for details.
>> #--------------------------------------------------------------------------
>> ajets leading jet pT = 48.0278
>> Segmentation fault: 11
>> 
>> 
>> 
>> 
>> 
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