Re: [boost] [units]

From: Steven Watanabe (steven_at_[hidden])
Date: 2007-03-05 16:56:06

AMDG

Matthias Schabel <boost <at> schabel-family.org> writes:

> 
> >>   a) It might be handy, though, to have (for example) a log function
> >>   that enforces unitless quantities.  For example,
> >>
> >>      log ( velocity * time / meters )
> >>
> >>   is fine, but if you forget to multiply by the time, you get a
> >>   helpful error message.
> 
> Cases where the function argument reduces to a dimensionless quantity
> already all work because dimensionless quantities can be implicitly
> converted to their value type :
> 
> std::cout << std::sqrt(quantity<SI::velocity> 
> (9.0*SI::meters_per_second)*SI::seconds/SI::meters) << std::endl;
> 
> gives
> 
> 3

But they cannot be found by ADL and they return the
raw value_type.  The preferable output from your example
would be

3 dimensionless

In Christ,
Steven Watanabe