Re: Reasons (not) to vote Motion 27: NO

[Arnold Neumaier <Arnold.Neumaier@xxxxxxxxxxxx>]

On 08/18/2011 12:17 PM, Vincent Lefevre wrote:
> On 2011-08-17 19:13:48 +0200, Arnold Neumaier wrote:
> > Since you compute a function of two variables, you need to apply
> > domain to the vector consisting of both variables, not to each
> > variable separately!
>
> I don't know exactily who would be responsible for applying domain,
> but I think this is counter-intuitive. If I write:
>
>    z = sqrt(x) + y;
>
> I don't expect the computation of sqrt(x) to depend on y.
>
> If this is the user who is responsible for applying domain on the
> vector explicitly before the expression, then there are risks of
> mistakes (unless the language forbids expressions and works only
> on functions with explicit parameters).

In any serious programming there is risk of mistakes, and one needs to 
know some precautions to avoid the most common fallacies.

Note also that a good program would catch an emoty initial interval 
before even trying to evaluate some expression. And an empty interval 
created during a range evaluation doesn't cause problems.

Arnold Neumaier