RE: [boost] Dimensional Analysis Interest? RV: [boost] Staticcompile-time fractions

From: Paul A. Bristow (boost_at_[hidden])
Date: 2003-10-22 13:51:11

This was not unnoticed and definitely is of interest.  Suggest you should post
your work so far, and examples of use, prefably annotated.

I note your use of rational dimensions to allow fractional (but not log and
exp).

I'm inclined to agree that Beman's 'gas mix' problem may be too difficult to
handle, for the reasons you give.

Paul

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

-----Original Message-----
From: boost-bounces_at_[hidden] [mailto:boost-bounces_at_[hidden]]On
Behalf Of González Cuadrado, Miguel
Sent: Monday, October 20, 2003 12:06 PM
To: Boost mailing list
Subject: [boost] Dimensional Analysis Interest? RV: [boost] Staticcompile-time
fractions

This posting went apparently unnoticed, but it may be of interest to the
"Dimensional Analysis" thread.
<big snip>

By the way, IMHO the question about mixing gasoline is out of scope, since it is
an altogether different problem, with very different semantics: fundamental
dimensions are not multiplied as in dimensional analysis, but summed. It doesn't
even support the same set of operations (no subtraction, semantics for
multiplication is bscure, no division...).

I have developed a small library that allows to do compile-time computations
using rational numbers; it is heavily template-based. I use as a part of a units
library (yet another), in which the dimension is encoded as seven rational
numbers, one for the exponent of each of length, time, temperature and so on;
each of these rational numbers is a template argument for a magnitude with
dimension. (Fractional dimension units are used sometimes, for example for turbo
engine analysis and simulation.