[boost] Re: Physical Quantities revisited

From: Andy Little (andy_at_[hidden])
Date: 2003-10-16 21:48:22

"Paul A. Bristow" <boost_at_[hidden]> wrote in message
news:AHEJIHEOOOBMJPAGPLIPKELKEGAA.boost_at_hetp.u-net.com...
> I hate to be negative about your proposal (unlike many Boosters who seem
to take
> great delight in shooting/shouting anything down) but having glanced at
the code
> examples, I really don't think that this is the right way to go.  I still
think
> that everything should be held internally in SI units - now that double
has
> enough range to cover almost everyones needs.

"Almost everyone" includes ... well you presumably.
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)

  I'm worried about conversion
> loss - your first example warns of the danger.

I guess I should tell users that if they dont use SI units they'd better go
elsewhere because if we convert we'll lose the 32nd decimal place in the
conversion ?

 And I am worried about the
> expansion to other all the types of units - many are unecessary (feet
even!) but
> widely used.

In the U.K.... but not Cumbria I guess
every road sign is in ...er. miles per hour. .. So you dont do H.M contracts
for political reaasons :-)
head for Europe and you have k.m.h... Ok no problem avoid European contracts
in case you encounter these unnecessary units.
Many Americans use imperial units... just stupid I guess :-(
In the butcher 90% of people still ask for a pound of beef. no till/accounts
contracts.
Every wood yard worker must be able convert feet to metres....

Unit conversion is a real problem now!

> | http://www.servocomm.freeserve.co.uk/Cpp/physical_quantity/index.html

regards
Andy Little
andy_at_[hidden]