[Rivet] Segfault with two analyses

[David Grellscheid]

Hi Tom,

without looking at any specifics, the most likely cause is in accessing
vector items that don't exist. Let's say you need the momentum of the
4th jet somewhere, and use jets[3].momentum(). However, not all events
will actually have 4 jets, so once a problematic event is generated, you
get an out-of-bounds access, which may cause a segfault, but will not do
so every time. Every vector access needs to be protected by making sure
it can only be called on vectors of the required size.

Please check your code for these kinds of problem first. If it still
doesn't work, let us know. Please send your Rivet code and Herwig input
file at that time.

See you,

   David