[Rivet] PartonicTops not found

[Mazuza Mohammad A Ghneimat]

Hello,

I would like to have the invariant mass of the two top partons, so that I am including the PartonicTops class to find tops: 
#include "Rivet/Projections/PartonicTops.hh
But it complains that fatal error: Rivet/Projections/PartonicTops.hh: No such file or directory

Does that mean this object isn’t available anymore? I am finding a bit difficulty to find tops, any suggestions?
(my process is top pair production with emission of a photon, I produced my analysis input file using MADGRAPH+PYTHIA8)

Thanks,
 Mazuza