The functions from ROOT::Math::VectorUtil
are in libGenVector
which is loaded automatically in neither CINT nor PyROOT. Manually loading it (like you probably do in your root_logon.C
) makes the functions available, e.g.
import ROOT as r
r.gSystem.Load('libGenVector')
# ...
r.Math.VectorUtil.DeltaR(jets[i],partons[i])