Re: [Boost-users] [Units] Require help troubleshooting a template error with linear_algebra.hpp

Subject: Re: [Boost-users] [Units] Require help troubleshooting a template error with linear_algebra.hpp
From: eddyaod_at_[hidden]
Date: 2011-12-11 13:28:51

Hi Stephen,

I don't have much experience with creating new units and new systems in
Boost Units, but I find that the predefined units and systems and prefixes
already have most needs covered. For example, see:

http://www.boost.org/doc/libs/1_48_0/doc/html/boost_units/Examples.html#boost_units.Examples.RadarBeamHeightExample

for the use of "kilo*meters".

Of course you can typedef your own kilometer, if you absolutely must, as in:

http://www.boost.org/doc/libs/1_48_0/doc/html/boost_units/Units.html#boost_units.Units.scaled_base_units

Furthermore, you can static_cast between quantities (as long as the
conversion is defined somewhere [it already is for degrees and radians]).
See:

http://www.boost.org/doc/libs/1_48_0/doc/html/boost_units/Quantities.html#boost_units.Quantities.Conversions

Lastly, creating a dimensionless angle type is possible but I would advise
against it, as it then puts you in the territory of not being able to
distinguish between solid angular quantities and pseudovectors, and breaks
your interoperability with all the provided angular units. See the first 2
points in this FAQ for some rationale behind angles:

http://www.boost.org/doc/libs/1_48_0/doc/html/boost_units/FAQ.html#boost_units.FAQ.Distinguishing_Quantities_With_Same_Units

The situation does sometimes lead to code that doesn't look as elegant as
the maths did on paper, but it does maintain correctness which leads to
less uncertainty about its operation.

Best of luck with using Boost.Units, I hope the above links help a little.

Regards,

Edmund Fokschaner

On 9 December 2011 16:30, Stephen Torri <stephen.torri_at_[hidden]> wrote:

> Below is a dump of the build output from compiling the stand alone
> example. In order to understand what I am doing I am trying to setup a
> boost unit system where length is in kilometers, angle is in degrees
> and time is in minutes. I would like to have the ability to enter
> automatically convert angles from degrees to radians. In addition I am
> attemping to make the angle types I use to be dimensionless.
>
> Regards,
> Stephen
>
> -----------
> 1>Compiling...
> 1>boost_units.cpp
> 1>C:\boost\boost/units/detail/linear_algebra.hpp(342) : error C3083:
> 'item': the symbol to the left of a '::' must be a type
> 1>        C:\boost\boost/units/detail/linear_algebra.hpp(310) : see
> reference to class template instantiation
>
> 'boost::units::detail::invert_handle_inital_rows<0>::apply<RowsBegin,IdentityBegin>'
> being compiled
> 1>        with
> 1>        [
> 1>
>  RowsBegin=boost::units::list<boost::units::detail::eliminate_from_pair_of_equations_impl<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::static_rational<0,1>,boost::units::static_rational<1>>::type,boost::units::detail::invert_handle_after_pivot_row<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>>::new_matrix>,
> 1>
>  IdentityBegin=boost::units::list<boost::units::list<boost::units::static_rational<-1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension,boost::units::static_rational<1>>,boost::units::dimensionless_type>>::type,boost::units::list<boost::units::static_rational<1>,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::detail::invert_handle_after_pivot_row<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>>::identity_result>
> 1>        ]
> 1>        C:\boost\boost/units/detail/linear_algebra.hpp(310) : see
> reference to class template instantiation
>
> 'boost::units::detail::invert_handle_inital_rows<N>::apply<RowsBegin,IdentityBegin>'
> being compiled
> 1>        with
> 1>        [
> 1>            N=1,
> 1>
>  RowsBegin=boost::units::list<boost::units::dimensionless_type,boost::units::list<boost::units::detail::eliminate_from_pair_of_equations_impl<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::static_rational<0,1>,boost::units::static_rational<1>>::type,boost::units::detail::invert_handle_after_pivot_row<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>>::new_matrix>>,
> 1>
>  IdentityBegin=boost::units::list<boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::list<boost::units::list<boost::units::static_rational<-1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension,boost::units::static_rational<1>>,boost::units::dimensionless_type>>::type,boost::units::list<boost::units::static_rational<1>,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::detail::invert_handle_after_pivot_row<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>>::identity_result>>
> 1>        ]
> 1>        C:\boost\boost/units/detail/linear_algebra.hpp(501) : see
> reference to class template instantiation
>
> 'boost::units::detail::invert_handle_inital_rows<N>::apply<RowsBegin,IdentityBegin>'
> being compiled
> 1>        with
> 1>        [
> 1>            N=2,
> 1>
>  RowsBegin=boost::units::list<boost::units::detail::eliminate_from_pair_of_equations_impl<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::static_rational<0,1>,boost::units::static_rational<1>>::type,boost::units::list<boost::units::dimensionless_type,boost::units::list<boost::units::detail::eliminate_from_pair_of_equations_impl<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::static_rational<0,1>,boost::units::static_rational<1>>::type,boost::units::detail::invert_handle_after_pivot_row<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>>::new_matrix>>>,
> 1>
>  IdentityBegin=boost::units::list<boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::list<boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::list<boost::units::list<boost::units::static_rational<-1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension,boost::units::static_rational<1>>,boost::units::dimensionless_type>>::type,boost::units::list<boost::units::static_rational<1>,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::detail::invert_handle_after_pivot_row<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>>::identity_result>>>
> 1>        ]
> 1>        C:\boost\boost/units/detail/linear_algebra.hpp(503) : see
> reference to class template instantiation
> 'boost::units::detail::invert_impl<N>::apply<RowsBegin,IdentityBegin>'
> being compiled
> 1>        with
> 1>        [
> 1>            N=1,
> 1>
>  RowsBegin=boost::units::list<boost::units::detail::eliminate_from_pair_of_equations_impl<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::static_rational<0,1>,boost::units::static_rational<1>>::type,boost::units::list<boost::units::dimensionless_type,boost::units::list<boost::units::detail::eliminate_from_pair_of_equations_impl<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::static_rational<0,1>,boost::units::static_rational<1>>::type,boost::units::detail::invert_handle_after_pivot_row<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>>::new_matrix>>>,
> 1>
>  IdentityBegin=boost::units::list<boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::list<boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::list<boost::units::list<boost::units::static_rational<-1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension,boost::units::static_rational<1>>,boost::units::dimensionless_type>>::type,boost::units::list<boost::units::static_rational<1>,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::detail::invert_handle_after_pivot_row<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>>::identity_result>>>
> 1>        ]
> 1>        C:\boost\boost/units/detail/linear_algebra.hpp(503) : see
> reference to class template instantiation
> 'boost::units::detail::invert_impl<N>::apply<RowsBegin,IdentityBegin>'
> being compiled
> 1>        with
> 1>        [
> 1>            N=2,
> 1>
>  RowsBegin=boost::units::list<boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>,boost::units::list<boost::units::list<boost::units::static_rational<1>,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>,boost::units::list<boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>,boost::units::detail::determine_extra_equations_impl<0>::apply<boost::units::dimensionless_type,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>::type>>>,
> 1>
>  IdentityBegin=boost::units::list<boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::list<boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::list<boost::units::list<boost::units::static_rational<-1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension,boost::units::static_rational<1>>,boost::units::dimensionless_type>>::type,boost::units::list<boost::units::static_rational<1>,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::detail::invert_handle_after_pivot_row<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>>::identity_result>>>
> 1>        ]
> 1>        C:\boost\boost/units/detail/linear_algebra.hpp(542) : see
> reference to class template instantiation
> 'boost::units::detail::invert_impl<N>::apply<RowsBegin,IdentityBegin>'
> being compiled
> 1>        with
> 1>        [
> 1>            N=3,
> 1>
>  RowsBegin=boost::units::list<boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>,boost::units::list<boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension,boost::units::static_rational<1>>,boost::units::dimensionless_type>>::type,boost::units::list<boost::units::static_rational<1>,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>,boost::units::list<boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>,boost::units::dimensionless_type>>>,
> 1>
>  IdentityBegin=boost::units::list<boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::list<boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::list<boost::units::list<boost::units::static_rational<0,1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension,boost::units::static_rational<1>>,boost::units::dimensionless_type>>::type,boost::units::list<boost::units::static_rational<1>,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>>,boost::units::detail::make_identity<0>::apply<3>::type>>>
> 1>        ]
> 1>        C:\boost\boost/units/detail/linear_algebra.hpp(828) : see
> reference to class template instantiation
> 'boost::units::detail::make_square_and_invert<Matrix>' being compiled
> 1>        with
> 1>        [
> 1>
>  Matrix=boost::units::list<boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>,boost::units::list<boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::list<boost::units::dim<boost::units::plane_angle_base_dimension,boost::units::static_rational<1>>,boost::units::dimensionless_type>>::type,boost::units::list<boost::units::static_rational<1>,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>,boost::units::list<boost::units::list<boost::units::static_rational<1>,boost::units::list<boost::units::detail::calculate_base_dimension_coefficients_func<false>::apply<boost::units::dimensionless_type>::type,boost::units::detail::expand_dimensions<0>::apply<boost::units::dimensionless_type,boost::units::dimensionless_type>::type>>,boost::units::dimensionless_type>>>
> 1>        ]
> 1>        C:\boost\boost/units/detail/linear_algebra.hpp(1032) : see
> reference to class template instantiation
> 'boost::units::detail::normalize_units<T>' being compiled
> 1>        with
> 1>        [
> 1>
>  T=boost::units::list<myproject::units::minute_base_unit,boost::units::list<myproject::units::angle::degree_base_unit,boost::units::list<myproject::units::earth::kilometer_base_unit,boost::units::dimensionless_type>>>
> 1>        ]
> 1>        C:\boost\boost/units/detail/linear_algebra.hpp(1051) : see
> reference to class template instantiation
>
> 'boost::units::detail::calculate_base_unit_exponents_impl<false>::apply<T,Dimensions>'
> being compiled
> 1>        with
> 1>        [
> 1>
>  T=boost::units::list<myproject::units::minute_base_unit,boost::units::list<myproject::units::angle::degree_base_unit,boost::units::list<myproject::units::earth::kilometer_base_unit,boost::units::dimensionless_type>>>,
> 1>            Dimensions=boost::units::length_dimension
> 1>        ]
> 1>        C:\boost\boost/units/heterogeneous_system.hpp(243) : see
> reference to class template instantiation
> 'boost::units::detail::calculate_base_unit_exponents<T,Dimensions>'
> being compiled
> 1>        with
> 1>        [
> 1>
>  T=boost::units::list<myproject::units::minute_base_unit,boost::units::list<myproject::units::angle::degree_base_unit,boost::units::list<myproject::units::earth::kilometer_base_unit,boost::units::dimensionless_type>>>,
> 1>            Dimensions=boost::units::length_dimension
> 1>        ]
> 1>        C:\boost\boost/units/unit.hpp(92) : see reference to class
> template instantiation
> 'boost::units::detail::make_heterogeneous_system<Dimensions,System>'
> being compiled
> 1>        with
> 1>        [
> 1>            Dimensions=boost::units::length_dimension,
> 1>            System=myproject::units::earth::system
> 1>        ]
> 1>        C:\boost\boost/units/unit.hpp(99) : see reference to class
> template instantiation 'boost::units::reduce_unit<Unit>' being
> compiled
> 1>        with
> 1>        [
> 1>
>  Unit=boost::units::unit<boost::units::length_dimension,myproject::units::earth::system>
> 1>        ]
> 1>        ..\..\..\apps\boost_units\boost_units.cpp(81) : see
> reference to class template instantiation
> 'boost::units::is_implicitly_convertible<S1,S2>' being compiled
> 1>        with
> 1>        [
> 1>
>  S1=boost::units::unit<boost::units::length_dimension,myproject::units::earth::system>,
> 1>
>  S2=boost::units::unit<boost::units::length_dimension,myproject::units::earth::system>
> 1>        ]
> 1>C:\boost\boost/units/detail/linear_algebra.hpp(342) : error C2039:
> 'Numerator' : is not a member of 'boost::units::dimensionless_type'
> 1>        C:\boost\boost/units/dimensionless_type.hpp(37) : see
> declaration of 'boost::units::dimensionless_type'
> 1>C:\boost\boost/units/detail/linear_algebra.hpp(342) : error C2065:
> 'Numerator' : undeclared identifier
>
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