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From Al Chou <>
Subject Re: [math] Complex dilemmas
Date Wed, 11 Jun 2003 23:03:47 GMT
--- "J.Pietschmann" <> wrote:
> Al Chou wrote:
> > Thanks for the input, Roger.  I think for FFT's in particular, we would
> want to
> > profile whether using a complex number class would be fast enough compared
> to
> > using two primitive doubles.  The "Fast" in "Fast Fourier Transform" should
> be
> > preserved as much as possible, IMHO.
> Don't waste your time: FFT is actually easier to implement
> using double primitives, it's also likely to be faster, and
> if you really want to get the last performance percent, cache
> locality is a major factor which is even more a point against
> using a Complex class.

Thanks for the commentary!  I've never coded FFT's myself, so I didn't want to
come down too hard on the idea of using complex number objects in the absence
of experience, even though I suspected what you said.

> Study the Great Internet Mersenne Prime search sources for
> an interesting read about the problems (high precision
> number multiplication is basically FFT too).

Cool reference, thanks.  Did you mean "study the source code"?  There don't
seem to be any expositive materials on the subject at their site

> I personally found usage of complex numbers only natural for
> certain EE calculations (involving alternate current) and
> advcanced scientific computation. All other areas of financial
> math, statistics, civil and mechanical engineering can do
> quite comfortably without using complex numbers.

That's my general feeling, too.


Albert Davidson Chou

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