[Boost-users] [units] Problem with conversion of compound units

Subject: [Boost-users] [units] Problem with conversion of compound units
From: Norman, Ben (bnorman_at_[hidden])
Date: 2014-05-20 18:10:31

First, thanks for the most excellent boost::units library.  We are making good use of it in a scientific software project.  I confess that there more than a few things that remain mysterious to me, but I'll focus on one example here:
----------------------------------------------------------------
#include <iostream>

#include <boost/units/make_scaled_unit.hpp>
#include <boost/units/systems/si.hpp>

using namespace std;
using namespace boost::units;

/** @brief electron volts */
struct ev_base_unit :
  public base_unit<ev_base_unit, energy_dimension, 9999>{
  /** @brief Get the unit name */
  static const char* name() { return "electron-Volt"; }
  /** @brief Get the unit symbol */
  static const char* symbol() { return "eV"; }
};
typedef ev_base_unit::unit_type ev_unit;
BOOST_UNITS_STATIC_CONSTANT(eV, ev_unit);

// keV
typedef make_scaled_unit<ev_unit, 
                        scale<10, static_rational<3> > >::type kev_unit;
BOOST_UNITS_STATIC_CONSTANT(keV, kev_unit);

// can only define conversion from a base unit.
BOOST_UNITS_DEFINE_CONVERSION_FACTOR(ev_base_unit, si::energy, double,
                                     1.60217653e-19);

// without this, conversion from si::energy to eV doesn't work
BOOST_UNITS_DEFAULT_CONVERSION(ev_base_unit, si::energy);

int main(int argc, char **argv){

  // "natural" direction (ev -> joule)
  cerr << "conversion ev to joule: "
       <<  conversion_factor(eV, si::joule) << endl;
  cerr << "conversion kev/s to joule/s: "
       <<  conversion_factor(keV/si::second, si::joule/si::second) << endl;

  // "reverse" direction (joule -> ev)
  cerr << "conversion joule to ev: "
       << conversion_factor(si::joule, eV) << endl;
  cerr << "conversion from joule/s to kev/s: "
       << conversion_factor(si::joule/si::second, keV/si::second) << endl;

  // eV to keV conversions
  cerr << "conversion ev to kev: "
       << conversion_factor(eV, keV) << endl;
  cerr << "conversion ev/s to kev/s: "
    // Fails to compile:
       << conversion_factor(eV/si::second, keV/si::second)
       << endl;

  return 0;
}
----------------------------------------------------------------

When compiling the program above with gcc 4.8.2 and boost 1.54, I get the error below.  All the conversions for eV and keV to and from joules work fine (even when divided by time as a test), but going between eV/second and keV/second explodes.  Is this a limitation of make_scaled_unit?  I have also tried with scaled_base_unit, but the results are the same.

Thanks for any help,
Ben


In file included from /usr/include/boost/units/heterogeneous_system.hpp:39:0,
                 from /usr/include/boost/units/make_scaled_unit.hpp:15,
                 from test.cpp:3:
/usr/include/boost/units/detail/linear_algebra.hpp: In instantiation of ‘struct boost::units::detail::determine_extra_equations_skip_zeros_impl<true, false>::apply<boost::units::list<boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<1l>, boost::units::dimensionless_type> >, boost::units::dimensionless_type>, 1, 1, 3, boost::units::list<boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<1l>, boost::units::dimensionless_type> > >, boost::units::list<boost::units::list<boost::units::static_rational<2l>, boost::units::list<boost::units::static_rational<1l>, boost::units::list<boost::units::static_rational<-2l>, boost::units::dimensionless_type> > >, boost::units::dimensionless_type> > >’:
/usr/include/boost/units/detail/linear_algebra.hpp:259:54:   required from ‘struct boost::units::detail::determine_extra_equations<2, false>::apply<boost::units::list<boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<1l>, boost::units::dimensionless_type> >, boost::units::dimensionless_type>, 3, boost::units::list<boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<1l>, boost::units::dimensionless_type> > >, boost::units::list<boost::units::list<boost::units::static_rational<2l>, boost::units::list<boost::units::static_rational<1l>, boost::units::list<boost::units::static_rational<-2l>, boost::units::dimensionless_type> > >, boost::units::dimensionless_type> > >’
/usr/include/boost/units/detail/linear_algebra.hpp:264:17:   required from ‘struct boost::units::detail::determine_extra_equations<3, false>::apply<boost::units::list<boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<1l>, boost::units::dimensionless_type> > >, boost::units::list<boost::units::list<boost::units::static_rational<2l>, boost::units::list<boost::units::static_rational<1l>, boost::units::list<boost::units::static_rational<-2l>, boost::units::dimensionless_type> > >, boost::units::dimensionless_type> >, 3, boost::units::list<boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<1l>, boost::units::dimensionless_type> > >, boost::units::list<boost::units::list<boost::units::static_rational<2l>, boost::units::list<boost::units::static_rational<1l>, boost::units::list<boost::units::static_rational<-2l>, boost::units::dimensionless_type> > >, boost::units::dimensionless_type> > >’
/usr/include/boost/units/detail/linear_algebra.hpp:538:13:   required from ‘struct boost::units::detail::make_square_and_invert<boost::units::list<boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<1l>, boost::units::dimensionless_type> > >, boost::units::list<boost::units::list<boost::units::static_rational<2l>, boost::units::list<boost::units::static_rational<1l>, boost::units::list<boost::units::static_rational<-2l>, boost::units::dimensionless_type> > >, boost::units::dimensionless_type> > >’
/usr/include/boost/units/detail/linear_algebra.hpp:828:59:   required from ‘struct boost::units::detail::normalize_units<boost::units::list<boost::units::si::second_base_unit, boost::units::list<ev_base_unit, boost::units::dimensionless_type> > >’
/usr/include/boost/units/detail/linear_algebra.hpp:1035:17:   [ skipping 2 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/usr/include/boost/units/heterogeneous_system.hpp:243:93:   required from ‘struct boost::units::detail::make_heterogeneous_system<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<1l> >, boost::units::dimensionless_type>, boost::units::homogeneous_system<boost::units::list<boost::units::si::second_base_unit, boost::units::list<ev_base_unit, boost::units::dimensionless_type> > > >’
/usr/include/boost/units/unit.hpp:93:7:   required from ‘struct boost::units::reduce_unit<boost::units::unit<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<1l> >, boost::units::dimensionless_type>, boost::units::homogeneous_system<boost::units::list<boost::units::si::second_base_unit, boost::units::list<ev_base_unit, boost::units::dimensionless_type> > >, void> >’
/usr/include/boost/units/detail/conversion_impl.hpp:314:89:   required from ‘struct boost::units::detail::conversion_impl<2>::apply<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-1l> >, boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >, boost::units::homogeneous_system<boost::units::list<boost::units::si::second_base_unit, boost::units::list<ev_base_unit, boost::units::dimensionless_type> > > >’
/usr/include/boost/units/detail/conversion_impl.hpp:445:13:   required from ‘struct boost::units::detail::conversion_factor_helper<boost::units::unit<boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-1l> >, boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >, boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::dimensionless_type> >, void>, boost::units::unit<boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-1l> >, boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >, boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::list<boost::units::scale_list_dim<boost::units::scale<10l, boost::units::static_rational<3l> > >, boost::units::dimensionless_type> > >, void> >’
/usr/include/boost/units/conversion.hpp:176:1:   required by substitution of ‘template<class FromUnit, class ToUnit> typename boost::units::one_to_double_type<typename boost::units::detail::conversion_factor_helper<Source, Dest>::type>::type boost::units::conversion_factor(const FromUnit&, const ToUnit&) [with FromUnit = boost::units::unit<boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-1l> >, boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >, boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::dimensionless_type> >, void>; ToUnit = boost::units::unit<boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-1l> >, boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >, boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::list<boost::units::scale_list_dim<boost::units::scale<10l, boost::units::static_rational<3l> > >, boost::units::dimensionless_type> > >, void>]’
test.cpp:50:58:   required from here
/usr/include/boost/units/detail/linear_algebra.hpp:197:48: error: no type named ‘item’ in ‘boost::units::list<boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<1l>, boost::units::dimensionless_type> >, boost::units::dimensionless_type>::next {aka struct boost::units::dimensionless_type}’
         typedef typename RowsBegin::next::item next_row;
                                                ^
/usr/include/boost/units/detail/linear_algebra.hpp:199:39: error: no type named ‘item’ in ‘boost::units::list<boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<1l>, boost::units::dimensionless_type> >, boost::units::dimensionless_type>::next {aka struct boost::units::dimensionless_type}’
             next_row::item::Numerator == 0,
                                       ^
/usr/include/boost/units/detail/linear_algebra.hpp:199:39: error: no type named ‘item’ in ‘boost::units::list<boost::units::list<boost::units::static_rational<0l, 1l>, boost::units::list<boost::units::static_rational<1l>, boost::units::dimensionless_type> >, boost::units::dimensionless_type>::next {aka struct boost::units::dimensionless_type}’
/usr/include/boost/units/detail/linear_algebra.hpp: In instantiation of ‘struct boost::units::detail::calculate_base_unit_exponents_impl<false>::apply<boost::units::list<boost::units::si::second_base_unit, boost::units::list<ev_base_unit, boost::units::dimensionless_type> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >’:
/usr/include/boost/units/detail/linear_algebra.hpp:1051:122:   required from ‘struct boost::units::detail::calculate_base_unit_exponents<boost::units::list<boost::units::si::second_base_unit, boost::units::list<ev_base_unit, boost::units::dimensionless_type> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >’
/usr/include/boost/units/heterogeneous_system.hpp:243:93:   required from ‘struct boost::units::detail::make_heterogeneous_system<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<1l> >, boost::units::dimensionless_type>, boost::units::homogeneous_system<boost::units::list<boost::units::si::second_base_unit, boost::units::list<ev_base_unit, boost::units::dimensionless_type> > > >’
/usr/include/boost/units/unit.hpp:93:7:   required from ‘struct boost::units::reduce_unit<boost::units::unit<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<1l> >, boost::units::dimensionless_type>, boost::units::homogeneous_system<boost::units::list<boost::units::si::second_base_unit, boost::units::list<ev_base_unit, boost::units::dimensionless_type> > >, void> >’
/usr/include/boost/units/detail/conversion_impl.hpp:314:89:   required from ‘struct boost::units::detail::conversion_impl<2>::apply<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-1l> >, boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >, boost::units::homogeneous_system<boost::units::list<boost::units::si::second_base_unit, boost::units::list<ev_base_unit, boost::units::dimensionless_type> > > >’
/usr/include/boost/units/detail/conversion_impl.hpp:445:13:   required from ‘struct boost::units::detail::conversion_factor_helper<boost::units::unit<boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-1l> >, boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >, boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::dimensionless_type> >, void>, boost::units::unit<boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-1l> >, boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >, boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::list<boost::units::scale_list_dim<boost::units::scale<10l, boost::units::static_rational<3l> > >, boost::units::dimensionless_type> > >, void> >’
/usr/include/boost/units/conversion.hpp:176:1:   required by substitution of ‘template<class FromUnit, class ToUnit> typename boost::units::one_to_double_type<typename boost::units::detail::conversion_factor_helper<Source, Dest>::type>::type boost::units::conversion_factor(const FromUnit&, const ToUnit&) [with FromUnit = boost::units::unit<boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-1l> >, boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >, boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::dimensionless_type> >, void>; ToUnit = boost::units::unit<boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<boost::units::si::second_base_unit, boost::units::static_rational<-1l> >, boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type> >, boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-3l> >, boost::units::dimensionless_type> > >, boost::units::list<boost::units::scale_list_dim<boost::units::scale<10l, boost::units::static_rational<3l> > >, boost::units::dimensionless_type> > >, void>]’
test.cpp:50:58:   required from here
/usr/include/boost/units/detail/linear_algebra.hpp:1045:96: error: could not convert template argument ‘boost::units::detail::normalize_units<boost::units::list<boost::units::si::second_base_unit, boost::units::list<ev_base_unit, boost::units::dimensionless_type> > >::extra’ to ‘int’
         typedef typename strip_zeroes_impl<base_solutions::extra>::template apply<units>::type type;
                                                                                                ^
test.cpp: In function ‘int main(int, char**)’:
test.cpp:50:58: error: no matching function for call to ‘conversion_factor(boost::units::divide_typeof_helper<boost::units::unit<boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-2l> >, boost::units::dimensionless_type> > >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type>, boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-2l> >, boost::units::dimensionless_type> > >, boost::units::dimensionless_type> >, void>, boost::units::unit<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<1l> >, boost::units::dimensionless_type>, boost::units::homogeneous_system<boost::units::list<boost::units::si::meter_base_unit, boost::units::list<boost::units::scaled_base_unit<boost::units::cgs::gram_base_unit, boost::units::scale<10l, boost::units::static_rational<3l> > >, boost::units::list<boost::units::si::second_base_unit, boost::units::list<boost::units::si::ampere_base_unit, boost::units::list<boost::units::si::kelvin_base_unit, boost::units::list<boost::units::si::mole_base_unit, boost::units::list<boost::units::si::candela_base_unit, boost::units::list<boost::units::angle::radian_base_unit, boost::units::list<boost::units::angle::steradian_base_unit, boost::units::dimensionless_type> > > > > > > > > > > >::type, boost::units::divide_typeof_helper<boost::units::unit<boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-2l> >, boost::units::dimensionless_type> > >, boost::units::heterogeneous_system<boost::units::heterogeneous_system_impl<boost::units::list<boost::units::heterogeneous_system_dim<ev_base_unit, boost::units::static_rational<1l> >, boost::units::dimensionless_type>, boost::units::list<boost::units::dim<boost::units::length_base_dimension, boost::units::static_rational<2l> >, boost::units::list<boost::units::dim<boost::units::mass_base_dimension, boost::units::static_rational<1l> >, boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<-2l> >, boost::units::dimensionless_type> > >, boost::units::list<boost::units::scale_list_dim<boost::units::scale<10l, boost::units::static_rational<3l> > >, boost::units::dimensionless_type> > >, void>, boost::units::unit<boost::units::list<boost::units::dim<boost::units::time_base_dimension, boost::units::static_rational<1l> >, boost::units::dimensionless_type>, boost::units::homogeneous_system<boost::units::list<boost::units::si::meter_base_unit, boost::units::list<boost::units::scaled_base_unit<boost::units::cgs::gram_base_unit, boost::units::scale<10l, boost::units::static_rational<3l> > >, boost::units::list<boost::units::si::second_base_unit, boost::units::list<boost::units::si::ampere_base_unit, boost::units::list<boost::units::si::kelvin_base_unit, boost::units::list<boost::units::si::mole_base_unit, boost::units::list<boost::units::si::candela_base_unit, boost::units::list<boost::units::angle::radian_base_unit, boost::units::list<boost::units::angle::steradian_base_unit, boost::units::dimensionless_type> > > > > > > > > > > >::type)’
        << conversion_factor(eV/si::second, keV/si::second)
                                                          ^
test.cpp:50:58: note: candidate is:
In file included from /usr/include/boost/units/quantity.hpp:29:0,
                 from /usr/include/boost/units/systems/si.hpp:19,
                 from test.cpp:4:
/usr/include/boost/units/conversion.hpp:176:1: note: template<class FromUnit, class ToUnit> typename boost::units::one_to_double_type<typename boost::units::detail::conversion_factor_helper<Source, Dest>::type>::type boost::units::conversion_factor(const FromUnit&, const ToUnit&)
 conversion_factor(const FromUnit&,const ToUnit&)
 ^
/usr/include/boost/units/conversion.hpp:176:1: note:   substitution of deduced template arguments resulted in errors seen above