1 /* fft/c_init.c
2 *
3 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007, 2009 Brian Gough
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 3 of the License, or (at
8 * your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 */
19
TYPE(gsl_fft_complex_wavetable)20 TYPE(gsl_fft_complex_wavetable) *
21 FUNCTION(gsl_fft_complex_wavetable,alloc) (size_t n)
22 {
23 int status ;
24 size_t i;
25 size_t n_factors;
26 size_t t, product, product_1, q;
27 double d_theta;
28
29 TYPE(gsl_fft_complex_wavetable) * wavetable ;
30
31 if (n == 0)
32 {
33 GSL_ERROR_VAL ("length n must be positive integer", GSL_EDOM, 0);
34 }
35
36 wavetable = (TYPE(gsl_fft_complex_wavetable) *)
37 malloc(sizeof(TYPE(gsl_fft_complex_wavetable)));
38
39 if (wavetable == NULL)
40 {
41 GSL_ERROR_VAL ("failed to allocate struct", GSL_ENOMEM, 0);
42 }
43
44 wavetable->trig = (TYPE(gsl_complex) *) malloc (n * sizeof (TYPE(gsl_complex)));
45
46 if (wavetable->trig == NULL)
47 {
48 free(wavetable) ; /* error in constructor, prevent memory leak */
49
50 GSL_ERROR_VAL ("failed to allocate trigonometric lookup table",
51 GSL_ENOMEM, 0);
52 }
53
54 wavetable->n = n ;
55
56 status = fft_complex_factorize (n, &n_factors, wavetable->factor);
57
58 if (status)
59 {
60 /* exception in constructor, avoid memory leak */
61
62 free (wavetable->trig);
63 free (wavetable);
64
65 GSL_ERROR_VAL ("factorization failed", GSL_EFACTOR, 0);
66 };
67
68 wavetable->nf = n_factors;
69
70 d_theta = -2.0 * M_PI / ((double) n);
71
72 t = 0;
73 product = 1;
74 for (i = 0; i < n_factors; i++)
75 {
76 size_t j;
77 const size_t factor = wavetable->factor[i];
78 wavetable->twiddle[i] = wavetable->trig + t;
79 product_1 = product; /* product_1 = p_(i-1) */
80 product *= factor;
81 q = n / product;
82
83 for (j = 1; j < factor; j++)
84 {
85 size_t k;
86 size_t m = 0;
87 for (k = 1; k <= q; k++)
88 {
89 double theta;
90 m = m + j * product_1;
91 m = m % n;
92 theta = d_theta * m; /* d_theta*j*k*p_(i-1) */
93 GSL_REAL(wavetable->trig[t]) = cos (theta);
94 GSL_IMAG(wavetable->trig[t]) = sin (theta);
95
96 t++;
97 }
98 }
99 }
100
101 if (t > n)
102 {
103 /* exception in constructor, avoid memory leak */
104
105 free (wavetable->trig);
106 free (wavetable);
107
108 GSL_ERROR_VAL ("overflowed trigonometric lookup table",
109 GSL_ESANITY, 0);
110 }
111
112 return wavetable;
113 }
114
115
TYPE(gsl_fft_complex_workspace)116 TYPE(gsl_fft_complex_workspace) *
117 FUNCTION(gsl_fft_complex_workspace,alloc) (size_t n)
118 {
119 TYPE(gsl_fft_complex_workspace) * workspace ;
120
121 if (n == 0)
122 {
123 GSL_ERROR_VAL ("length n must be positive integer", GSL_EDOM, 0);
124 }
125
126 workspace = (TYPE(gsl_fft_complex_workspace) *)
127 malloc(sizeof(TYPE(gsl_fft_complex_workspace)));
128
129 if (workspace == NULL)
130 {
131 GSL_ERROR_VAL ("failed to allocate struct", GSL_ENOMEM, 0);
132 }
133
134 workspace->n = n ;
135
136 workspace->scratch = (BASE *) malloc (2 * n * sizeof (BASE));
137
138 if (workspace->scratch == NULL)
139 {
140 free(workspace) ; /* error in constructor, prevent memory leak */
141
142 GSL_ERROR_VAL ("failed to allocate scratch space", GSL_ENOMEM, 0);
143 }
144
145 return workspace;
146 }
147
148
149 void
FUNCTION(gsl_fft_complex_wavetable,free)150 FUNCTION(gsl_fft_complex_wavetable,free) (TYPE(gsl_fft_complex_wavetable) * wavetable)
151 {
152 RETURN_IF_NULL (wavetable);
153 /* release trigonometric lookup tables */
154
155 free (wavetable->trig);
156 wavetable->trig = NULL;
157
158 free (wavetable) ;
159 }
160
161 void
FUNCTION(gsl_fft_complex_workspace,free)162 FUNCTION(gsl_fft_complex_workspace,free) (TYPE(gsl_fft_complex_workspace) * workspace)
163 {
164 RETURN_IF_NULL (workspace);
165 /* release scratch space */
166
167 free (workspace->scratch);
168 workspace->scratch = NULL;
169 free (workspace) ;
170 }
171
172
173 int
FUNCTION(gsl_fft_complex,memcpy)174 FUNCTION(gsl_fft_complex,memcpy) (TYPE(gsl_fft_complex_wavetable) * dest,
175 TYPE(gsl_fft_complex_wavetable) * src)
176 {
177 int i, n, nf ;
178
179 if (dest->n != src->n)
180 {
181 GSL_ERROR ("length of src and dest do not match", GSL_EINVAL);
182 }
183
184 n = dest->n ;
185 nf = dest->nf ;
186
187 memcpy(dest->trig, src->trig, n * sizeof (double)) ;
188
189 for (i = 0 ; i < nf ; i++)
190 {
191 dest->twiddle[i] = dest->trig + (src->twiddle[i] - src->trig) ;
192 }
193
194 return 0 ;
195 }
196