Re: [boost] SIunits and quantity library concerns

From: Dean Foster (foster_at_[hidden])
Date: 2001-10-03 21:12:20

Walter Brown wrote: 

> I've stayed out of this discussion for a few weeks now to see whether a
> consensus would form, but it seems not yet.

Thanks for re-entering the discussion.  As the primary source of line
noise in this discussion let me first apologize for my incorrect use
of language.  

Using the correct language, I now realize that I basically wrote and
used a quantities library rather than a units library.  From that
project, I learned that user defined quantities are important.  From
the discussion on the news group I now admit that user defined units
are probably a very bad idea.  But, user defined quantities like
"apples", "oranges", "fruits", etc are important from the programming
perspective.  Further when such quantities are multiplied, the
underlieing dimensions should not be lost.  (i.e. if the fruits are
measured in Kgs, multiplying apples times time can't simply yield kg*s
it must be (kgs of apples)*(seconds).)  This one idea is the only
thing that I feel I've learned from creating and using a quantities
library.

Sorry again for trying to communicate this point using incorrect
language.  (I actually use the wrong language when I teach also--as
one would imagine it drives the students crazy!)

later,

dean

=============================================================================
Dean Foster                                                   dean_at_[hidden]
Statistics, Wharton, U. Penn                                     215 898 8233
Philadelphia PA 19104-6302                 http://diskworld.wharton.upenn.edu