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- /* fft/signals_source.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.
- */
- #include "gsl_fft__signals.h"
- int
- FUNCTION(fft_signal,complex_pulse) (const size_t k,
- const size_t n,
- const size_t stride,
- const BASE z_real,
- const BASE z_imag,
- BASE data[],
- BASE fft[])
- {
- size_t j;
- if (n == 0)
- {
- GSL_ERROR ("length n must be positive integer", GSL_EDOM);
- }
- /* gsl_complex pulse at position k, data[j] = z * delta_{jk} */
- for (j = 0; j < n; j++)
- {
- REAL(data,stride,j) = 0.0;
- IMAG(data,stride,j) = 0.0;
- }
- REAL(data,stride,k % n) = z_real;
- IMAG(data,stride,k % n) = z_imag;
- /* fourier transform, fft[j] = z * exp(-2 pi i j k / n) */
- for (j = 0; j < n; j++)
- {
- const double arg = -2 * M_PI * ((double) ((j * k) % n)) / ((double) n);
- const BASE w_real = (BASE)cos (arg);
- const BASE w_imag = (BASE)sin (arg);
- REAL(fft,stride,j) = w_real * z_real - w_imag * z_imag;
- IMAG(fft,stride,j) = w_real * z_imag + w_imag * z_real;
- }
- return 0;
- }
- int
- FUNCTION(fft_signal,complex_constant) (const size_t n,
- const size_t stride,
- const BASE z_real,
- const BASE z_imag,
- BASE data[],
- BASE fft[])
- {
- size_t j;
- if (n == 0)
- {
- GSL_ERROR ("length n must be positive integer", GSL_EDOM);
- }
- /* constant, data[j] = z */
- for (j = 0; j < n; j++)
- {
- REAL(data,stride,j) = z_real;
- IMAG(data,stride,j) = z_imag;
- }
- /* fourier transform, fft[j] = n z delta_{j0} */
- for (j = 0; j < n; j++)
- {
- REAL(fft,stride,j) = 0.0;
- IMAG(fft,stride,j) = 0.0;
- }
- REAL(fft,stride,0) = ((BASE) n) * z_real;
- IMAG(fft,stride,0) = ((BASE) n) * z_imag;
- return 0;
- }
- int
- FUNCTION(fft_signal,complex_exp) (const int k,
- const size_t n,
- const size_t stride,
- const BASE z_real,
- const BASE z_imag,
- BASE data[],
- BASE fft[])
- {
- size_t j;
- if (n == 0)
- {
- GSL_ERROR ("length n must be positive integer", GSL_EDOM);
- }
- /* exponential, data[j] = z * exp(2 pi i j k) */
- for (j = 0; j < n; j++)
- {
- const double arg = 2 * M_PI * ((double) ((j * k) % n)) / ((double) n);
- const BASE w_real = (BASE)cos (arg);
- const BASE w_imag = (BASE)sin (arg);
- REAL(data,stride,j) = w_real * z_real - w_imag * z_imag;
- IMAG(data,stride,j) = w_real * z_imag + w_imag * z_real;
- }
- /* fourier transform, fft[j] = z * delta{(j - k),0} */
- for (j = 0; j < n; j++)
- {
- REAL(fft,stride,j) = 0.0;
- IMAG(fft,stride,j) = 0.0;
- }
- {
- int freq;
- if (k <= 0)
- {
- freq = (n-k) % n ;
- }
- else
- {
- freq = (k % n);
- };
- REAL(fft,stride,freq) = ((BASE) n) * z_real;
- IMAG(fft,stride,freq) = ((BASE) n) * z_imag;
- }
- return 0;
- }
- int
- FUNCTION(fft_signal,complex_exppair) (const int k1,
- const int k2,
- const size_t n,
- const size_t stride,
- const BASE z1_real,
- const BASE z1_imag,
- const BASE z2_real,
- const BASE z2_imag,
- BASE data[],
- BASE fft[])
- {
- size_t j;
- if (n == 0)
- {
- GSL_ERROR ("length n must be positive integer", GSL_EDOM);
- }
- /* exponential, data[j] = z1 * exp(2 pi i j k1) + z2 * exp(2 pi i j k2) */
- for (j = 0; j < n; j++)
- {
- const double arg1 = 2 * M_PI * ((double) ((j * k1) % n)) / ((double) n);
- const BASE w1_real = (BASE)cos (arg1);
- const BASE w1_imag = (BASE)sin (arg1);
- const double arg2 = 2 * M_PI * ((double) ((j * k2) % n)) / ((double) n);
- const BASE w2_real = (BASE)cos (arg2);
- const BASE w2_imag = (BASE)sin (arg2);
- REAL(data,stride,j) = w1_real * z1_real - w1_imag * z1_imag;
- IMAG(data,stride,j) = w1_real * z1_imag + w1_imag * z1_real;
- REAL(data,stride,j) += w2_real * z2_real - w2_imag * z2_imag;
- IMAG(data,stride,j) += w2_real * z2_imag + w2_imag * z2_real;
- }
- /* fourier transform, fft[j] = z1 * delta{(j - k1),0} + z2 *
- delta{(j - k2,0)} */
- for (j = 0; j < n; j++)
- {
- REAL(fft,stride,j) = 0.0;
- IMAG(fft,stride,j) = 0.0;
- }
- {
- int freq1, freq2;
- if (k1 <= 0)
- {
- freq1 = (n - k1) % n;
- }
- else
- {
- freq1 = (k1 % n);
- };
- if (k2 <= 0)
- {
- freq2 = (n - k2) % n;
- }
- else
- {
- freq2 = (k2 % n);
- };
- REAL(fft,stride,freq1) += ((BASE) n) * z1_real;
- IMAG(fft,stride,freq1) += ((BASE) n) * z1_imag;
- REAL(fft,stride,freq2) += ((BASE) n) * z2_real;
- IMAG(fft,stride,freq2) += ((BASE) n) * z2_imag;
- }
- return 0;
- }
- int
- FUNCTION(fft_signal,complex_noise) (const size_t n,
- const size_t stride,
- BASE data[],
- BASE fft[])
- {
- size_t i;
- int status;
- if (n == 0)
- {
- GSL_ERROR ("length n must be positive integer", GSL_EDOM);
- }
- for (i = 0; i < n; i++)
- {
- REAL(data,stride,i) = (BASE)urand();
- IMAG(data,stride,i) = (BASE)urand();
- }
- /* compute the dft */
- status = FUNCTION(gsl_dft_complex,forward) (data, stride, n, fft);
- return status;
- }
- int
- FUNCTION(fft_signal,real_noise) (const size_t n,
- const size_t stride,
- BASE data[],
- BASE fft[])
- {
- size_t i;
- int status;
- if (n == 0)
- {
- GSL_ERROR ("length n must be positive integer", GSL_EDOM);
- }
- for (i = 0; i < n; i++)
- {
- REAL(data,stride,i) = (BASE)urand();
- IMAG(data,stride,i) = 0.0;
- }
- /* compute the dft */
- status = FUNCTION(gsl_dft_complex,forward) (data, stride, n, fft);
- return status;
- }
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