Re: No on Motion P1788/M007.01_NaI
Dear Hossam,
> interval xx;
>
> yy = xx + [1,3];
>
> uses xx without initializing it. This might be acceptable in a declarative
> language that will keep moving through the program till it finds a value for
> either yy or xx and derive one from the other. However, for an imperative
> language this code is problematic. I argue that in our standard, we must
> specify a "non-initialized" datum for xx till it is really initialized by
> the programmer. If such a "non-initialized" datum is used in a calculation,
> the standard should specify how the system (whether done in hardware or SW)
> will handle this case. A human doing interval arithmetic on paper will not
> face this problem, but a computer does.
In a declarative language, this would be a programmer critical error!
In the case of non intitialized intervals, we could maybe overcome the
problem requiring a interval to be initialized with [-oo,+oo], but I
am not sure whether this removes all problems or not...
Anyway, though IA is meant to change non rigorous computations to
rigorous one, we cannot aim at handling programmers error.
Kind regards,
Alexandre Goldsztejn
> --
> Hossam A. H. Fahmy
> Assistant Professor
> Electronics and Communications Department
> Cairo University
> Egypt
>
>
>
--
Dr. Alexandre Goldsztejn
CNRS - University of Nantes
Office : +33 2 51 12 58 37 Mobile : +33 6 78 04 94 87
Web: www.goldsztejn.com
Email: alexandre.goldsztejn@xxxxxxxxxxxxxx