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

From: Reece Dunn (msclrhd_at_[hidden])
Date: 2004-01-11 23:17:31

>Deane Yang 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.

Dan W. wrote:
>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.

Also, doesn't special relativity make use of 4-vectors/quaternions? I agree 
that the dimension/unit/physical quantity information is a decoration to the 
data (e.g. inform the compiler that the type has the units kilometers / 
hour).

Regards,
Reece

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