Hi, I need to use the boost::units::atan2() function in boost/units/cmath.hpp, but am having trouble figuring out how. Do the units have to be dimensionless, or can they be any unit? I have two variables, x_ and y_ which are of a scaled unit type, called light_second_unit. I'm calling it like this: boost::units::atan2(y_, x_); I get this error: ./physics/cartesian_coordinate_system/point.cpp:85: error: no matching function for call to `atan2(boost::units::quantity<boost::units::astronomical::light_second_unit, double>, boost::units::quantity<boost::units::astronomical::light_second_unit, double>)' If it has to be dimensionless, how do I convert them to a dimensionless quantity? Thanks, Brandon -- www.creatorspiritus.com Blog and forum discussing living a Christ-centered life Follow me on Twitter: http://twitter.com/devbanana Follow creatorspiritus.com on Twitter: http://twitter.com/creatorspiritus