Re: [boost] [Review][PQS] Review deadline

From: John Phillips (phillips_at_[hidden])
Date: 2006-06-08 18:02:54

Gerhard Wesp wrote:

 > Sorry, I don't have the time to read the PQS documentation in-depth
 > right now.
 >
 > Still, I'd like to make one suggestion.
 >
 > I think that handling of dimensional quantities and conversion factors
 > are orthogonal concepts and should be separated.
 >
 > I suggest that for maximum transparency the library should *exclusively*
 > handle quantities expressed in SI units.
 >
 > I'm aware that this "mildly forces" developers to adopt SI units.  I
 > consider this a Good Thing.

I disagree.
In my work, most quantities are transformed into some set of simulation
units that are only rarely SI units, and I believe this to be true of
much other scientific programming. The basis for chosing the units is
instead attempting to maximize numeric stability, and so choosing units
that keep things as close to order 1 as possible. Then, since real world
units are the measured inputs, and the useful outputs, simple
conversions are done at the beginning and end.
As such, I prefer the current approach of the library that allows for
non-SI units (though not eaily, yet).

                        John Phillips