<div dir="ltr"><div><div>Thank you very much! I read that in useJetArea() but was not sure how to get around it. Your line " fj.useJetArea(new fastjet::AreaDefinition(fastjet::VoronoiAreaSpec()));" works perfectly. Passing it by value was a typo! </div>Cheers, </div>Alan </div><div class="gmail_extra"> <div class="gmail_quote">On Mon, Oct 17, 2016 at 4:47 PM, Andy Buckley <<a href="mailto:andy.buckley@cern.ch" target="_blank">andy.buckley@cern.ch</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On 17/10/16 15:29, Alan Kaptanoglu wrote: <div><div class="h5"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Hello, I am trying to declare jets with area in the initialization section of my Rivet Analysis. I originally tried: fastjet::GhostedAreaSpec areaspec(2.5,1,0.01); fastjet::AreaDefinition area_def(fastjet::active_area_explicit_ghosts,areaspec); FastJets jets(vfs, FastJets::ANTIKT, Rsmall); jets.useJetArea(area_def); jets.useInvisibles(JetAlg::ALL_INVISIBLES); jets.useMuons(JetAlg::DECAY_MUONS); declare(jets, "jets"); but this definition goes out of scope so when I ask for jet areas in my "analysis" section of my code, it complains the jets have no valid jet area associated with them. I next tried several versions of: areaspec = new fastjet::GhostedAreaSpec(2.5,1,0.01); area_def = new fastjet::AreaDefinition(fastjet::active_area_explicit_ghosts,*areaspec); FastJets jets(vfs, FastJets::ANTIKT, Rsmall); jets.useJetArea(area_def); jets.useInvisibles(JetAlg::ALL_INVISIBLES); jets.useMuons(JetAlg::DECAY_MUONS); declare(jets, "jets"); where areaspec and area_def are private members of my Analysis class. I also tried initializing these variables in my constructor using initialization lists, as well as declaring them global variables (and yes, to my knowledge, I am also deleting them correctly if I use "new"). In all these cases, the code runs correctly but complains at the end of a memory error, which is attached in a text file. Any idea why this is happening or how to fix? </blockquote> </div></div> Hi Alan, The AreaDefinition provided to FastJets must be a heap-allocated pointer whose ownership is then taken over by the FastJets object: it will delete the pointer at the end of the run so you shouldn't try to do that yourself. (This is documented on the useJetArea() function) To this end I usually make sure that I don't have a variable of my own pointing at that area def objects, e.g. fj.useJetArea(new fastjet::AreaDefinition(fastjet::VoronoiAreaSpec())); As you noticed, if you pass in a locally allocated object, it goes out of scope and you get a crash. Although I'm not sure how you're able to pass it in by value rather than by pointer! I would like, if possible, to avoid this pointer ownership stuff in the FastJets interface... I'm sure it's possible, just needs a bit of care and thought about backward compatibility. Pointers were used historically because we need the option of a null AreaDefinition, and there's no such thing as a null reference in C++. Hope that helps, Andy -- Dr Andy Buckley, Lecturer / Royal Society University Research Fellow Particle Physics Expt Group, University of Glasgow </blockquote></div> </div>