Re: [boost] Stream input and output of NaN and infinity

From: Damien Fisher (damienf_at_[hidden])
Date: 2006-05-16 01:24:50

On 5/16/06, Robert Ramey <ramey_at_[hidden]> wrote:
>
> David Abrahams wrote:
> > Not only break, but break unfixably.  There are important numerical
> > applications where large collections of individual floating values
> > (e.g. vectors and matrices) have to be computed in parallel, and one
> > or more NaNs in the result do not render the whole calculation
> > useless.
>
> I suppose that's possible. I'm not familiar with such applications.
> It sounds to me that they would be implemented in special hardware
> and sort of out of the C++ mainstream.

[Sorry to jump into the thread so late...but I just can't resist.  And
apologies for the cut-off post.]

Have you ever heard of SSE/MMX/...?  Vectorization is a very common
optimization these days, and that's on commodity intel boxes.

It really seems to me that you are objecting to a numerical model which has
worked well for decades in numerous domains and into which much effort has
been expended.

The IEEE standard wasn't cooked up at random.  If you have objections to the
semantics I'd suggest you try coming up with a full proposal that works as
well.  That's probably the best way to realize why things are the way they
are ;).

(FWIW, I used to have problems with NaN/Inf back in the day too...)

Damien