Re: [boost] [review][constrained_value] Review of Constrained Value Library begins today

Subject: Re: [boost] [review][constrained_value] Review of Constrained Value Library begins today
From: Thorsten Ottosen (thorsten.ottosen_at_[hidden])
Date: 2008-12-11 16:27:17

Robert Kawulak skrev:
> 2008/12/11 Thorsten Ottosen <thorsten.ottosen_at_[hidden]>:
>> We need to make either x or y one of the bounds of our interval. Let us
>> assume it is y.
>>
>> Furthermore, we know y has been specified such that it is representable
>> exactly in float or double.
> 
> Not necessarily:
> 
>     typedef bounded<float>::type bfloat;
> 
>     bfloat ouch( sin(x), bfloat::constraint_type( cos(y), tan(z) ) );
>     ouch = log(7);
> 
> Any of the bounds or the underlying value may be extended during
> computations involved in both the construction and the assignment (if
> I understand correctly), there's no guarantee that the compiler will
> not optimise away storage of the values.

Well, in most of my use cases the bounds are defined at compile time. As 
for your example, then I hope we find a way to force this rounding.

> And actually what "truncation" is -- really a truncation (rounding
> towards 0), or rounding to the nearest representable value?

I think it is usually rounding towards nearest.

-Thorsten