FFT support libraries

Steffen Persvold sp at scali.no
Thu Jul 26 19:56:30 PDT 2001


Greg Lindahl wrote:
> 
> On Thu, Jul 26, 2001 at 10:10:03PM +0200, Steffen Persvold wrote:
> 
> > I'm trying to port a fortran application using SGI FFT functions
> > (complib.sgimath) to Linux. The only FFT functions that are used are
> > zfft1di and zfft1d. I understand that these are double complex
> > functions and I've downloaded the double precision fftpack from
> > netlib.org (dfftpack). However, the dfftpack routines zffti and
> > zfft{f,b} doesn't seem to match the SGI functions.
> 
> Welcome to Fourier Transform Hell. No 2 libraries are the same, for
> no good reason.
> 
> > Now, here I guess that the direction parameter to ZFFT1D is just a
> > way to decide wether to use a forward or a backward FFT, but what is
> > the parameter after E_SLICE ??.
> 
> The manpage says that the parameter after E_SLICE is the stride of the
> array, which will be undoubtedly 1 in your code. This is a fairly
> unusual feature in a fft library.

Thanks Greg,

Now where did you find this manpage ? Is it online ??

Regards,

-- 
  Steffen Persvold               Systems Engineer
  Email : mailto:sp at scali.no     Scali AS (http://www.scali.com)
  Tlf   : (+47) 22 62 89 50      Olaf Helsets vei 6
  Fax   : (+47) 22 62 89 51      N-0621 Oslo, Norway




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