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From: Phil Richards (news_at_[hidden])
Date: 2004-01-11 13:53:55

On Fri, 09 Jan 2004 16:13:18 -0500, Dan W. wrote:
[in reply to me]
> And what percentage of C++ programmers are actually using those
> physics-only libraries?

What percentage of C++ programmers are doing dimensional analysis of other
types? What other problem domains are there? Please, give some examples.

To drive a generic design we need use-cases - so far we have "physical
quantities" and lots of people saying "you need generic support for
others". But as yet I haven't seen any other use-cases shown.
*Every* example so far has been in terms of physical quantities. (Of
course, I might have missed some :-)

> Just the fact that dimensional analysis is so applicable to so many
> areas presents a golden opportunity to come up with something more
> general and useful to all of us.

What other areas? Give an example - the example should show the set of
dimensions that act as the basis (defined in terms of specific units[*])
and some equations that need to be written.

That would be a *great* help to the discussion - my experience is with
real world modelling and a 7-dimension system works just fine. Yes, any
linearly independent set of physical dimensions would work, but a library
that supports a specific complete set would be applicable to all these
other cases.

> And what reasoning could possibly justify that SI units should NOT be a
> data file that works with a dimensional analysis core library, but that
> it 'should' be hard-wired into it?

I have never argued that SI is the only thing - in all libraries SI is
just a special case. The thing I'm trying to find out is what other
dimensional analysis use-cases there are. Dimensional analysis is about
mixing things of different unit and getting the right answer - I really
think we need (real) examples of non-physical quantity application areas.


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