Re: [Boost-users] [units] conversion_factor in the two directions

What you're missing is the conversion from s to m kg^-1 Eh^-1/2.  (I think the conversion factor should be sqrt(4.359744e-18))

you probably mean s to m kg^1/2 Eh^-1/2 and yes that is the conversion factor. Now, I have no idea what would be the syntax to transform from second to something with combined units BOOST_UNITS_DEFINE_CONVERSION_FACTOR( si::second, ???, double, sqrt(4.359744e-18) );

You could also make it work by adding BOOST_UNITS_DEFAULT_CONVERSION(     atomic::hartree_energy_base_unit,     si::energy );

that worked right away. What would be the drawback of using DEFAULT_CONVERSION macro? loss of precision perhaps? Thank you, Alfredo