<html> <head> <meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type"> </head> <body bgcolor="#FFFFFF" text="#000000"> On 04/11/15 14:18, David Grellscheid wrote: <blockquote cite="mid:563A13CB.5090609@durham.ac.uk" type="cite"> <blockquote type="cite"> <blockquote type="cite">Isn't Beams::IP always going to be (0; 0,0,0)? We used to have a PrimaryVertex projection and it was totally pointless. </blockquote> I'd still leave it in. ThePEG can generate IP offsets (although nobody uses them), and I could imagine other situations that we shouldn't lock out. </blockquote> Let me clarify why for once I'm in favour of a (slightly) more complicated option: the fact that all current generators produce (0,0,0,0) here is not enforced by any of the tools we use upstream, it's just a coincidence. HepMC allows any value in that field, so we should be able to handle any value there. David _______________________________________________ Rivet mailing list <a class="moz-txt-link-abbreviated" href="mailto:Rivet@projects.hepforge.org">Rivet@projects.hepforge.org</a> <a class="moz-txt-link-freetext" href="https://www.hepforge.org/lists/listinfo/rivet">https://www.hepforge.org/lists/listinfo/rivet</a> </blockquote> I have boiled down their code to these two lines of HepMC stuff: <blockquote>const HepMC::GenVertex* vtx = p.genParticle()->production_vertex(); Vector3 d(vtx->position().x(), vtx->position().y(), vtx->position().z()); </blockquote> It's not perfect but it's just two lines that hardly justify changes to the Particle class. I will put it into rivet like this now. A validation plot is attached. Thanks, Holger </body> </html>