aningful for quantities as it implies the presence of
        at least a multiplicative scale factor and, possibly, and affine linear offset.
        Macros for simplifying the definition of conversions between units can be
        found in <code class="computeroutput"><a class="link" href="Reference.html#header.boost.units.conversion_hpp" title="Header &lt;boost/units/conversion.hpp&gt;">boost/units/conversion.hpp</a></code>
        and <code class="computeroutput"><a class="link" href="Reference.html#head