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- /* fft/hc_unpack.c
- *
- * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 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 3 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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