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[bug-gsl] Re: Error in documentation of real FFT (2008-05-13)

From: Brian Gough <bjg@gnu.org>
Subject: Re: Error in documentation of real FFT
Date: Tue, 13 May 2008 19:34:27 +0100
To: Cristian Toraci <cristian.toraci@.............>
Cc: bug-gsl@gnu.org

At Mon, 12 May 2008 15:25:12 +0200,
Cristian Toraci wrote:
> The documantation for gsl_fft_real_radix2_transform says that the
> output can be sorted using gsl_fft_halfcomplex_unpack. The
> documantation of gsl_fft_halfcomplex_unpack says it can also be used
> to sort the output of gsl_fft_real_transform, but the output of
> gsl_fft_real_radix2_transform and gsl_fft_real_transform don't have
> the same storage. Actually I verified than
> gsl_fft_real_radix2_transform + gsl_fft_halfcomplex_unpack doesn't
> sort the data in the right way: the result is different from what
> you get converting the data to a complex array and transforming it
> with gsl_fft_complex_radix2_forward, but the result is correct if
> the output of gsl_fft_real_radix2_transform is sorted by hand.

Thanks for your email. The documentation should have referred to the
separate function gsl_fft_halfcomplex_radix2_unpack -- I will correct
that.

--
Brian Gough

GNU Scientific Library -
http://www.gnu.org/software/gsl/