dear all,

we are going to switch from hepmc 2.03.11 to hepmc 2.06.05. 
the used version won't be supported in the future.

there is a few packages in atlasreconstrucion which need to be changed:

http://atlas-computing.web.cern.ch/atlas-computing/links/distdirectory/nightlies/otherwebarea/nicos_web_areamig432bs5g4recopt/nicos_buildsummary_1.html

in packages:

fastcalosim
trkvertexfittervalidation
vrtsecinclusive
fatrasalgs
fatrastools
particlejettools
overlayvalidation
muontruthalgs
muontrackperformance
muonbetarefit

there is used fourvector::mag() function which is no more
defined in ver 2.06. 

to fix it, e.g. one can implement the mag function locally as 

+verbatim+
inline double package::mag(const hepmc::fourvector&amp; v) const {
  return std::sqrt( v.x()*v.x() + v.y()*v.y() + v.z()*v.z() );
}
-verbatim-

it would be helpful for us if package developers could provide
the fixed tags with appropriate changes.

cheers,
jan
