Steven, Thanks! That worked perfectly. I spent quite a bit of time trying to solve this problem and others similar to it, and could not find anything in the examples. Would it be reasonable if I were to take a bit of time to add this example to conversion.cpp (or whatever example you feel is appropriate) and add it to the documentation? Cheers! Andrew Hundt ------------------------------------------------------------------------- For those who search for boost.units conversion examples, here is a working solution boostUnits.cpp: #include #include #include #include #include #include <iostream> #include <iterator> #include <algorithm> typedef boost::units::divide_typeof_helper< boost::units::degree::plane_angle, boost::units::si::time >::type degrees_per_second; int main() { boost::units::quantity< boost::units::si::angular_velocity> m_speed((30.0*boost::units::si::radians_per_second)); std::cout << "m_speed rad/sec: " << m_speed << std::endl; std::cout << " m_speed deg/sec: "<< static_cast >(m_speed) << std::endl; uint32_t result = static_cast(static_cast

(m_speed).value()); std::cout << " int result: "<< result << std::endl;

return(0); } ------------------------------------------------------------------------- Output: g++ boostUnits.cpp ./a.out m_speed rad/sec: 30 s^-1 rad m_speed deg/sec: 1718.87 deg s^-1 int result: 1718 ------------------------------------------------------------------------- Steven Watanabe writes:

AMDG

On 12/1/2010 11:10 AM, Andrew Hundt wrote:

...

I have made my question more specific so it will be easier to answer. I need to make a conversion from a general angular_velocity to degrees/second.

There's no such thing as a general angular_velocity. I assume that you mean that you want to convert from radians/second to degrees/second.

...

To illustrate this problem the example boostUnits.cpp:

#include #include #include #include #include #include<iostream> #include<iterator> #include<algorithm>

int main() { boost::units::quantity< boost::units::si::angular_velocity> m_speed((30.0*boost::units::si::radians_per_second)); std::cout<< "m_speed: "<< m_speed<< std::endl;

uint32_t result =

static_cast(boost::units::quantityboost::units::si::angular_velocity,uint32_t(m_speed*boost::units::degree::degrees/boost::units::si::seconds).value());

...

std::cout<< " result:"<< result<< std::endl;

return(0); }

Try

typedef boost::units::divide_typeof_helper< boost::units::degree::plane_angle, boost::units::si::time

...

::type degrees_per_second;

static_cast >(m_speed);

In Christ, Steven Watanabe

Cheers! Andrew Hundt On Wed, Dec 1, 2010 at 2:10 PM, Andrew Hundt wrote:

I have made my question more specific so it will be easier to answer. I need to make a conversion from a general angular_velocity to degrees/second.

To illustrate this problem the example boostUnits.cpp:

#include #include #include #include #include #include <iostream> #include <iterator> #include <algorithm>

int main() { boost::units::quantity< boost::units::si::angular_velocity> m_speed((30.0*boost::units::si::radians_per_second)); std::cout << "m_speed: " << m_speed << std::endl;

uint32_t result = static_cast(boost::units::quantityboost::units::si::angular_velocity,uint32_t(m_speed*boost::units::degree::degrees/boost::units::si::seconds).value()); std::cout << " result: "<< result << std::endl;

return(0); }

Produces this compiler output:

g++ boostUnits.cpp /usr/local/include/boost/units/detail/conversion_impl.hpp: In static member function ‘static boost::units::quantity boost::units::conversion_helper, boost::units::quantity >::convert(const boost::units::quantity&) [with Unit1 = boost::units::unit >, boost::units::list >, boost::units::dimensionless_type>

...

, boost::units::heterogeneous_system >, boost::units::list >, boost::units::list >, boost::units::dimensionless_type> > , boost::units::list >, boost::units::list >, boost::units::dimensionless_type> , boost::units::dimensionless_type> >, void>, T1 = double, Unit2 = boost::units::unit >, boost::units::list >, boost::units::dimensionless_type> , boost::units::homogeneous_system > >, boost::units::list > > > > > > > > >, void>, T2 = unsigned int]’: /usr/local/include/boost/units/quantity.hpp:193: instantiated from ‘boost::units::quantity::quantity(const boost::units::quantity&, typename boost::disable_if::type, boost::units::detail::is_non_narrowing_conversion, mpl_::bool_<true>, mpl_::bool_<true>, mpl_::bool_<true> >, typename boost::units::detail::disable_if_is_same::type>::type*) [with Unit2 = boost::units::unit >, boost::units::list >, boost::units::dimensionless_type> , boost::units::heterogeneous_system >, boost::units::list >, boost::units::list >, boost::units::dimensionless_type> > , boost::units::list >, boost::units::list >, boost::units::dimensionless_type> , boost::units::dimensionless_type> >, void>, YY = double, Unit = boost::units::unit >, boost::units::list >, boost::units::dimensionless_type> , boost::units::homogeneous_system > >, boost::units::list > > > > > > > > >, void>, Y = unsigned int]’ boostUnits.cpp:16: instantiated from here /usr/local/include/boost/units/detail/conversion_impl.hpp:345: error: no matching function for call to ‘conversion_factor(boost::units::unit >, boost::units::list >, boost::units::dimensionless_type> , boost::units::heterogeneous_system >, boost::units::list >, boost::units::list >, boost::units::dimensionless_type> > , boost::units::list >, boost::units::list >, boost::units::dimensionless_type> , boost::units::dimensionless_type> >, void>&, boost::units::unit >, boost::units::list >, boost::units::dimensionless_type> , boost::units::homogeneous_system > >, boost::units::list > > > > > > > > >, void>&)’

What is the syntax to achieve the desired type specification and subsequent conversion? Do I need to specify a degrees_per_second unit, and if so, how?

Thank you in advance for your help.

Cheers! Andrew Hundt

On Tue, Nov 30, 2010 at 7:29 PM, Andrew Hundt wrote:

...

I need to make a conversion from a general angular_velocity to degrees/second. For example:

boost::units::quantity< boost::units::si::angular_velocity> m_speed((30.0*boost::units::si::radians_per_second)); uint32_t result = static_cast(boost::units::quantityboost::units::si::angular_velocity,uint32_t(m_speed*boost::units::degree::degrees/boost::units::si::seconds).value());

However it fails to compile in gcc 4.4, reporting: error:incomplete type '[type removed]' used in nested name specifier

Could someone explain the proper syntax to achieve the desired type specification and subsequent conversion? Do I need to specify a degrees_per_second unit, and if so, how? Thank you in advance for your help.

Cheers! Andrew Hundt