Re: Include language bindings? Re: Draft Standard Text, V02.1

[Dan Zuras Intervals <intervals08@xxxxxxxxxxxxxx>]

> Date: Tue, 16 Mar 2010 13:04:26 -0500
> From: "R. Baker Kearfott" <rbk@xxxxxxxxxxxxx>
> To: Dan Zuras Intervals <intervals08@xxxxxxxxxxxxxx>
> CC: Nate Hayes <nh@xxxxxxxxxxxxxxxxx>, stds-1788@xxxxxxxxxxxxxxxxx
> Subject: Re: Include language bindings? Re: Draft Standard Text, V02.1
> 
> Dan et al,
> 
> My view in the past is that the reformulation is the responsibility
> of the programmer.  Although this greatly simplifies compiler writing,
> and indeed, standard-writing, it requires the programmers know what
> they are doing.  One reason I favor this position is that I know of very
> few rearrangement rules that result in narrower interval values in all
> cases.
> 
> Best regards,
> 
> Baker
> 

	Baker,

	It is, or was, my position as well.

	It is a reasonable one.  And defensible on grounds of
	simplicity, clarity, transparency, & reproducibility.
	The programmer will get exactly what the programmer
	asks for.  No more, no less.

	Still, there is much to be gained by narrowing a
	calculated interval to something more resembling its
	true variance.  It would be best to teach programmers
	how to do this but the gains are there whether the
	programmer knows how or not.

	Nate, are there rules that always win?  And can they be
	stated simply, clearly, transparently, & reproducibly?

	I must presume that at least some of these optimizations
	are more than data dependent tricks that work in some
	cases & not others.  Can we at least standardize those
	first & make them available to the programmer?  Whether
	default or not?

	At least this would be a good place to start.

	Yours,

				Dan


	P.S. - It occurs to me there might be another way to go.
	I believe that the 1788 standard must be a pedagogical
	document as well as a normative one.  Therefore, could
	we write an extensive annex on algebraic reformulations
	that are known to improve results?  If complete enough,
	it is possible that the normative specification of 'Do
	exactly that which is written, no more, no less' when
	supplemented by a 'How to narrow your interval results'
	annex could suffice for a standard.  It could work.
	And it would be a far simpler standard.