[Rivet] Unsuitable error checking

[David Grellscheid]

Hi Frank,

> As far as I understand, this analysis really corrected back to the
> stable Higgs because it's combining the yy and 4l channel, so you
> indeed have to run it with a stable Higgs simulation.

We'll need to discuss this in Glasgow. That's just not the right way to 
deal with combinations. Tevatron Run 1 could just as well claim to need 
generator runs with showering and hadronization turned off.

> Or are you just complaining about the technicalities (printf, abort)
> of how that is handled?

That, too. Rivet should never kill the program it's called from. Print 
huge warning messages if you want, and of course, skip the event, but 
don't abort() on a test that isn't robust. I noticed it in a run 
combining all ATLAS analyses for a certain energy. It could also be a 
problem if several MEs are switched on, only one of which is Higgs.

> causing somebody to accidently waste lots of CPUh

That's really not our problem. The current situation would have wasted 
one day of _my_ time had I not noticed. I don't see why we need to 
favour one over the other.

See you soon!

   David