RE: Arrondi sur les flottants

Cela répond en partie à ma question : l'autre partie concerne l'arrondi des nombres réels non constants (issus de calcul).

Merci encore de votre réponse si rapide

Patrick FARAIL
Software Engineering Methods
Avionics & Simulation Products - EYYWI
AIRBUS France
Phone  : 33 (0)5 61 93 66 28
Fax : 33 (0)5 61 93 03 54
Mailto : [email protected]



-----Message d'origine-----
De : Laurent GUERBY [mailto:[email protected]]
Envoyé : jeudi 3 novembre 2005 10:51
À : FARAIL, Patrick
Cc : [email protected]
Objet : Re: [ada-france] Arrondi sur les flottants



En Ada 95, l'arrondi des constantes reelles est deterministe,
4.9(38) :

38    For a real static expression that is not part of a larger static
expression, and whose expected type is not a descendant of a formal scalar
type, the implementation shall round or truncate the value (according to the
Machine_Rounds attribute of the expected type) to the nearest machine number
of the expected type; if the value is exactly half-way between two machine
numbers, any rounding shall be performed away from zero. If the expected type
is a descendant of a formal scalar type, no special rounding or truncating is
required - normal accuracy rules apply (see Annex G).

Mais ce n'est peut-etre pas l'objet votre question.

Laurent

On Thu, 2005-11-03 at 10:24 +0100, FARAIL, Patrick wrote:
> Bonjour à tous,
> une petite question pour des spécialistes de l'implémentation des
> flottants et du GNAT. Nous utilisons le compilateur GNAT sur machine
> Sun/Solaris et nous nous posons la question suivante :
> si un flottant est compris entre deux  nombres représentables en
> machine comment le compilateur gère l'arrondi, au plus bas au plus
> haut. Est-ce configurable comme cela est le cas en C et si oui comment
> par un attribut du langage, une option de compilation ou autre ?
> 
> Merci de votre aide
> Patrick FARAIL
> Software Engineering Methods
> Avionics & Simulation Products - EYYWI
> AIRBUS France
> Phone  : 33 (0)5 61 93 66 28
> Fax : 33 (0)5 61 93 03 54
> Mailto :[email protected]
>
> 
>
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