[Rivet] compatibility issues between 2.2.0 and 2.X.X

[Niccolo' Moretti]

To rivet authors,

I would like to complain about all the recent modifications/deprecations 
occurred in Rivet in the last few updates.

Together with other physicists in other universities and institutions, 
I'm in charge of a study on the effects of different MC generators on 
particular processes.
One of the most important thing is therefore to set up an 
universal,common environment to compare the results. Some months ago we 
decided to use Rivet as a validation framework because of its simplicity 
and flexibility.

Now all of us are in a situation where the analysis source code and the 
output result depend on the used rivet version(and plugins therein). All 
the modifications and deprecations have been done without any 
retro-compatibility function, forcing us to do different outputs and 
codes according to the version, losing in this way the universality that 
we have been looked for.

Moreover, it's not  possible that such modifications, in some cases, 
have occurred between to contiguous versions, say 2.2.0 and 2.2.1.

You should know how it's difficult to set up a common environment among 
different universities, institutions, fields (theory and experiments), 
computer architectures and people, and of course, how it's difficult to 
reinstall or updates software in large clusters.

I hope that in the future all the deprecations will not be done 
instantaneously.

Regards,
Niccolo' Moretti