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#include <math.h>
#ifndef FALSE
#define FALSE (0)
#endif
#ifndef TRUE
#define TRUE (1)
#endif
typedef struct
{
double re;
double im;
} complex_t;
static inline complex_t
complex_mul (complex_t a, complex_t b)
{
complex_t r;
r.re = a.re * b.re - a.im * b.im;
r.im = a.re * b.im + a.im * b.re;
return r;
}
static inline complex_t
complex_add (complex_t a, complex_t b)
{
complex_t r;
r.re = a.re + b.re;
r.im = a.im + b.im;
return r;
}
static inline complex_t
complex_sub (complex_t a, complex_t b)
{
complex_t r;
r.re = a.re - b.re;
r.im = a.im - b.im;
return r;
}
static inline double
complex_mag (complex_t a)
{
return sqrt (a.re * a.re + a.im * a.im);
}
static inline double
complex_arg (complex_t a)
{
return fmod (atan2 (a.im, a.re) + 2 * M_PI, 2 * M_PI);
}
static inline complex_t
complex_from_mag_arg (double mag, double arg)
{
complex_t r;
r.re = mag * cos (arg);
r.im = mag * sin (arg);
return r;
}
static inline double
rad_to_degree (double theta)
{
return theta * (360.0 / (2 * M_PI));
}
void
fft (complex_t *buffer, int n);
void
ifft (complex_t *buffer, int n);
/* Fourier transform an n x n array */
void
fft_2d (complex_t *buffer, int n);
void
ifft_2d (complex_t *buffer, int n);
/* Shifts the zero component to the center of the array */
void
shift (complex_t *buffer, int n);
void
shift_2d (complex_t *buffer, int n);
void
fft_shift_2d (complex_t *buffer, int n);
void
ifft_shift_2d (complex_t *buffer, int n);
void
show_image (const char *name, complex_t *image, int n);
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