From Redmer:
Adds local rho parameter as an extension to the input event, so
that subsequent tasks in an analysis train can use it.
in fact, at the moment i have a personal analysis task (aimed at jet flow)
which
a) calculates a rho as a function of phi (taking into account v2 and
v3), this is then stored as a AliLocalRhoParameter object and added to
the aod/esd
b) does a lot of calculations / histogram filling specific to my
analysis (jet flow)
since a) might be of use to other analyses as well (e.g. rosi is showing
an interest in using it) i propose that i split my task into two
classes, one general class for a) which will then be just an additional
method for estimating rho, and a second analysis task for myself to
tinker with.