-- Main.CarlBlaksley - 2010-05-14

I'm currently using your wonderfull software to do part of my thesis work and I have a question about an error which I'm recieving during event generation.

Firstlly I'm using Feynrules to generate a custom model file for madgraph. In this model I'm adding a heavy majorana neutrino to the SM. I done several test runs of various process in order to check against know results and everything seems to work properly. I am also using pythia and pgs, both of which are called properly and seem to produce reasonable output. However when I use ./generate_events for the process e-p>N>jjj (where N is the newly defined heavy neutrino) and I request say 8000 events in the run card I get errors such as

Iteration 1 too large truncation 0.80087054 16448<br /> Iteration 2 too large truncation 0.776286553 14161<br /> Iteration 3 too large truncation 0.749106612 12168<br /> Iteration 4 too large truncation 0.713902874 10651<br /> Iteration 5 too large truncation 0.668213925 9604<br /> Iteration 6 too large truncation 0.608896207 8593<br /> Iteration 7 too large truncation 0.531810516 7968<br /> Iteration 8 too large truncation 0.431607365 7506<br /> Iteration 9 too large truncation 0.301343267 7040<br /> Iteration 10 too large truncation 0.131999941 6788<br /> Iteration 11 too few events 0.00611880098 5881<br /> Iteration 12 too large truncation 0.0102608429 6219<br /> Iteration 13 too few events 0.0031598871 4792<br /> Iteration 14 too few events 0.00374115521 5033<br /> Iteration 15 too few events 0.00438546641 5344<br /> Iteration 16 too few events 0.00509948601 5590<br /> Iteration 17 too few events 0.00600499241 5860<br /> Iteration 18 too few events 0.00767212702 6222<br /> Failed to find requested number of unweighted events 80000 6222<br /> Unable to get 80000 events. Writing 6222

and in the end I only get a fraction of the events I request. Each of my collaborators, working on different systems from their own model files are also getting similar errors.

So my question is: Is this something I can ignore and just combine events from multiple runs or is this an issue?

(In the case that it isn't a problem, I am also having difficult with the multi_run script. It doesn't seem to actually call madgraph (generate_events).)

Thank you very much in advance for your response and or help.

-Carl

P.S. I apologize in advance if this topic isn't in the correct area.