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/* fft/hc_unpack.c
*
* Copyright (C) 1996, 1997, 1998, 1999, 2000 Brian Gough
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
int
FUNCTION(gsl_fft_halfcomplex,unpack) (const BASE halfcomplex_coefficient[],
BASE complex_coefficient[],
const size_t stride, const size_t n)
{
size_t i;
if (n == 0)
{
GSL_ERROR ("length n must be positive integer", GSL_EDOM);
}
REAL(complex_coefficient,stride,0) = halfcomplex_coefficient[0];
IMAG(complex_coefficient,stride,0) = 0.0;
for (i = 1; i < n - i; i++)
{
const ATOMIC hc_real = halfcomplex_coefficient[(2 * i - 1) * stride];
const ATOMIC hc_imag = halfcomplex_coefficient[2 * i * stride];
REAL(complex_coefficient,stride,i) = hc_real;
IMAG(complex_coefficient,stride,i) = hc_imag;
REAL(complex_coefficient,stride,n - i) = hc_real;
IMAG(complex_coefficient,stride,n - i) = -hc_imag;
}
if (i == n - i)
{
REAL(complex_coefficient,stride,i) = halfcomplex_coefficient[(n - 1) * stride];
IMAG(complex_coefficient,stride,i) = 0.0;
}
return 0;
}
int
FUNCTION(gsl_fft_halfcomplex,radix2_unpack) (const BASE halfcomplex_coefficient[],
BASE complex_coefficient[],
const size_t stride, const size_t n)
{
size_t i;
if (n == 0)
{
GSL_ERROR ("length n must be positive integer", GSL_EDOM);
}
REAL(complex_coefficient,stride,0) = halfcomplex_coefficient[0];
IMAG(complex_coefficient,stride,0) = 0.0;
for (i = 1; i < n - i; i++)
{
const ATOMIC hc_real = halfcomplex_coefficient[i * stride];
const ATOMIC hc_imag = halfcomplex_coefficient[(n - i) * stride];
REAL(complex_coefficient,stride,i) = hc_real;
IMAG(complex_coefficient,stride,i) = hc_imag;
REAL(complex_coefficient,stride,n - i) = hc_real;
IMAG(complex_coefficient,stride,n - i) = -hc_imag;
}
if (i == n - i)
{
REAL(complex_coefficient,stride,i) = halfcomplex_coefficient[i * stride];
IMAG(complex_coefficient,stride,i) = 0.0;
}
return 0;
}
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