RE: [boost] Re: Re: Re: Re: quantity libraries

From: Paul A. Bristow (boost_at_[hidden])
Date: 2001-09-03 12:21:16

> -----Original Message-----
> From: Kevlin Henney [mailto:kevlin_at_[hidden]]
> Sent: Friday, August 31, 2001 10:20 AM
> To: boost_at_[hidden]
> Subject: [boost] Re: Re: Re: Re: quantity libraries
>

> Specifically what I was after was whether anyone was mixing radically
> different units that would suggest favouring two different underlying
> representations, eg megaparsecs and femtometres, and what issues they
> had encountered and resolved.
>

The main potential problem is the astronomers, but even a megaparasec is
only
about 3 million light years  where a light year is about 10^15 meter, the
base unit.

So even with float with a max of 10^38 there is quiet a bit of headroom,
and with double 10^308 there is plenty.

So I can't see what the problem is with always storing everything in SI
units.

(If templating can allow other base systems without cost, then OK,
but I think that there is massive merit in having everything in SI
internally,
and a package that does this is a must.

Paul

Dr Paul A Bristow, hetp Chromatography
Prizet Farmhouse
Kendal, Cumbria
LA8 8AB      UK
[phone]
Mobile [phone]
mailto:pbristow_at_[hidden]