| /* 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; |
| } |
| |