[boost] Re: Units libraries... (long reply)

From: Deane Yang (deane_yang_at_[hidden])
Date: 2004-01-11 17:05:01

Dan W. wrote:

>> Complex quanitities are for me clearly beyond the scope of
>> the current unit libraries. Higher dimensional analysis
>> is probably useful, but a lot trickier to implement.
>> 1-dimensional analysis serves 90% of the needs.
> 
> 
> This I take issue with:  Complex numbers are used everywhere to describe 
> time-changing phenomena, be it voltage, force, current or motion or 
> acceleration.  And there's nothing that a units library shouldn't be 
> able to handle about it.  If  v = t * u, where all have complex 
> representations, boils down to four v = t * u operations using double, 
> say, an addition and a subtraction.
> In fact, the units library doesn't even care that a complex 
> multiplication is taking place;  all it needs to do is decorate the 
> complex result to the right type of units, which is the same type as if 
> the operation were simple.
> 

Yes, I think I do want to concede this point. You generally can assign
units to a complex number, and the units library should work as 
advertised. Thanks!