[music-dsp] 0!=0?

Jon Watte hplus at mindcontrol.org
Wed Dec 4 17:30:00 EST 2002


Denormals and other special case values may slow you down a factor
10 - 1000 though, depending on architecture. It's still a neat
observation, though :-)

Cheers,

			/ h+


> -----Original Message-----
> From: music-dsp-admin at aulos.calarts.edu
> [mailto:music-dsp-admin at aulos.calarts.edu]On Behalf Of Jay Stelly
> Sent: Wednesday, December 04, 2002 4:36 PM
> To: 'music-dsp at shoko.calarts.edu'
> Subject: RE: [music-dsp] 0!=0?
>
>
> One cool thing to remember is that computers are actually fast
> enough now to
> iterate the entire 32-bit space in a short period of time.  So if
> I wanted a
> definitive answer to this question I would simply write a loop
> that iterated
> all 32 bit patterns, stuffed them into a float and then multiplied them by
> zero - outputting the ones that were not zero.  My guess is that
> you've got
> some NaN or INF value in there, but it's nice to be able to know the
> behavior definitively with a simple bit of test code.  You can actually
> write unit tests for simple 32-bit float or int functions that take the
> _entire_ domain of the function into account now.  That's pretty cool.
>
> Jay
>
> > -----Original Message-----
> > From: Russell Borogove [mailto:kaleja at estarcion.com]
> > Sent: Wednesday, December 04, 2002 4:01 PM
> > To: music-dsp at shoko.calarts.edu
> > Subject: Re: [music-dsp] 0!=0?
> >
> >
> > > should it be that x*0.0f (where x is some float, maybe very
> > large) in
> > > c++ does not evaluate to zero?
>
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