| -----Original Message-----
| From: boost-bounces@[...].org
| [mailto:boost-bounces@[...].org]On Behalf Of Andy Little
| Sent: Friday, October 03, 2003 4:55 PM
| To: boost@[...].org
| Subject: [boost] Physical Quantities revisited

| I have also had requests from users for ability to work
|  in (say) feet and inches etc rather than s.i. units.
|
| I have had a look at various physical quantities libraries
|  including the "quantities" library at boost,
| and SIunits at
| http://www.fnal.gov/docs/working-groups/fpcltf/Pkg/SIunits/doc/0SIunits.html
|
|  but they have an odd syntax.
|
| ie  both do something like:
|
| 	length mylength = 20 * metres(); //  here length is a type
|
| whereas what would seem to be more useful would be:
|
| 	metres myLength(20); 	// here metres is the type
| 					//*1 see footnote on explicit ctor
|
| The critical difference here is that the type is the
|  unit of dimension, rather than the dimension itself.
| As a programmer if I want to know the units
| of a variable they are encoded in the type
|  and if I can't decipher them I can do a conversion:

My recollection is that the consensus of previous discussions was that getting
all the values into SI units for all interval calculations was the preferred
strategy.
And I still believe that this has most advantages.

Only on input or output would other units, like multiples and/or Imperial be
used.

Paul

Paul A Bristow, Prizet Farmhouse, Kendal, Cumbria, LA8 8AB  UK
+44 1539 561830   Mobile +44 7714 33 02 04
mailto:pbristow@[...].com



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