RE: [boost] Re: Physical Quantities revisited

From: Paul A. Bristow (boost_at_[hidden])
Date: 2003-10-17 13:05:24

| -----Original Message-----
| From: boost-bounces_at_[hidden]
| [mailto:boost-bounces_at_[hidden]]On Behalf Of Andy Little
| Sent: Friday, October 17, 2003 3:48 AM
| To: boost_at_[hidden]
| Subject: [boost] Re: Physical Quantities revisited
|
| "Almost everyone" includes ... well you presumably.

You can 'Google' your way through the previous discussions about this, but I
think I speak for the majority of the opinions expressed.

| As usual embedded developers are ignored.
| (In embedded its relatively common to scale during a calc to prevent
| overflow. That is sometimes more important than absolute accuracy)

So your strategy may suit your applications better.

| In the U.K.... but not Cumbria
| I guess every road sign is in ...er. miles per hour ...  Yup!
< many examples snipped - the list could be endless! >
|
| Unit conversion is a real problem now!

Absolutely - and we need better tools to deal with them, but also to avoid
serious mistakes in calculation which led, for the most spectacular example, to
the Mars Lander to be a Mars Crasher instead.  The current discussion about
Dimensional Analysis is primarily directed at this aspect, with emphasis on
near-zero run-time cost, something especially important to you embedders.

It is obviously essential that any units system works with any dimensional
analysis system, something we haven't cracked yet.  Watch this space.  Meanwhile
have fun with your package.

Paul

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