[std-interval] C++ interval std

[J. Wolff v. Gudenberg]

George,
Very interesting indeed. I added a few comments
Juergen

George Corliss schrieb:
> FYI:
> 
> Wednesday, March 29, Sun Microsystems
> Ned Nedialkov and I (George Corliss)  with quite a few Sun people.
> Here is my visit report:
> 
> 
> C++ compiler developers:
> Steve Clamage <Stephen.Clamage at Sun.com>
> Lawrence Crowl <Lawrence.Crowl at Sun.com>
> 
> Steve and Lawrence are both members of the C++ Committee (J16),
> representing Sun. Steve is the chair of J16.  It was Lawrence
> who wrote the comment to the this group in early March about
> passing by value.
> 
> The discussion was quite wide ranging, but here are some points.
> 
> The standards committee is also considering user-defined literals.
> If they adopt something there, we can probably use whatever is
> adopted for our problems of literals in an interval context.
> 
> Sun has an open source release of its interval elementary functions,
> so the barrier to entry is low.  That means we CAN require math.h
> functions be provided in an interval standard.

We SHOULD do this, but perhaps not with last bit accuracy.
filib provides another open source implementation with guaranteed bounds
> 
> Lawrence feels strongly that the standard should be to pass by
> value.  Intervals are small data structures; by value allows them
> to be passed in registers for speed.  That is how the current Sun
> C++ compiler works.  There is no reason to follow the C++ complex
> standard.  The library is often taken as an example by coders, and
> there is no good reason to follow the tradition of C from 20 years
> ago that structures should be passed by reference.

I fully agree
> 
> I
> IEEE 754R
> David Hough <David.Hough at Sun.com>
> 
> IEEE 754R is nearly over.  It is likely to include
>    Decimal formats for floating point
>        (Should C++ IA standard permit decimal intervals?)
>  
   Quad precision
>        (Should C++ IA standard quad intervals?)
basic arithmetic operations should work via template instantiation.
of course that does not hold for elementary functions
>    Fused Multiply and Add
>        (I assume with directed rounding?
>         Great for interval linear algebra, too)
>    min/max
>        (I wonder how they handle NaN, infinity, etc.)
>    expression evaluation
>        (Don't remember what that means)

perhaps the distinction of interval constants and variables with some 
possible preprocessing, such that x-x = 0 ??

> Dr. George F. Corliss
> Electrical and Computer Engineering
> Marquette University
> PO Box 1881 
> 1515 W. Wisconsin Ave.
> Milwaukee WI 53201-1881 USA
> 414-288-6599; Fax: 288-5579; Dept. 288-6280
> Office: Haggerty Engineering 296
> George.Corliss at Marquette.edu
> 
> 
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