Digital Image Correlation Engine  Version 1.0
A modular, high-performance, image correlation tool used to compute full-field displacements and strains from digital images
kiss_fft.h
1 #ifndef KISS_FFT_H
2 #define KISS_FFT_H
3 
4 #include <stdlib.h>
5 #include <stdio.h>
6 #include <math.h>
7 #include <string.h>
8 
9 #ifdef __cplusplus
10 extern "C" {
11 #endif
12 
13 /*
14  ATTENTION!
15  If you would like a :
16  -- a utility that will handle the caching of fft objects
17  -- real-only (no imaginary time component ) FFT
18  -- a multi-dimensional FFT
19  -- a command-line utility to perform ffts
20  -- a command-line utility to perform fast-convolution filtering
21 
22  Then see kfc.h kiss_fftr.h kiss_fftnd.h fftutil.c kiss_fastfir.c
23  in the tools/ directory.
24 */
25 
26 #ifdef USE_SIMD
27 # include <xmmintrin.h>
28 # define kiss_fft_scalar __m128
29 #define KISS_FFT_MALLOC(nbytes) _mm_malloc(nbytes,16)
30 #define KISS_FFT_FREE _mm_free
31 #else
32 #define KISS_FFT_MALLOC malloc
33 #define KISS_FFT_FREE free
34 #endif
35 
36 
37 #ifdef FIXED_POINT
38 #include <sys/types.h>
39 # if (FIXED_POINT == 32)
40 # define kiss_fft_scalar int32_t
41 # else
42 # define kiss_fft_scalar int16_t
43 # endif
44 #else
45 # ifndef kiss_fft_scalar
46 /* default is float */
47 # define kiss_fft_scalar double
48 # endif
49 #endif
50 
52 typedef struct {
54  kiss_fft_scalar r;
56  kiss_fft_scalar i;
58 
59 typedef struct kiss_fft_state* kiss_fft_cfg;
60 
61 /*
62  * kiss_fft_alloc
63  *
64  * Initialize a FFT (or IFFT) algorithm's cfg/state buffer.
65  *
66  * typical usage: kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL);
67  *
68  * The return value from fft_alloc is a cfg buffer used internally
69  * by the fft routine or NULL.
70  *
71  * If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc.
72  * The returned value should be free()d when done to avoid memory leaks.
73  *
74  * The state can be placed in a user supplied buffer 'mem':
75  * If lenmem is not NULL and mem is not NULL and *lenmem is large enough,
76  * then the function places the cfg in mem and the size used in *lenmem
77  * and returns mem.
78  *
79  * If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough),
80  * then the function returns NULL and places the minimum cfg
81  * buffer size in *lenmem.
82  * */
83 
84 kiss_fft_cfg kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem);
85 
86 /*
87  * kiss_fft(cfg,in_out_buf)
88  *
89  * Perform an FFT on a complex input buffer.
90  * for a forward FFT,
91  * fin should be f[0] , f[1] , ... ,f[nfft-1]
92  * fout will be F[0] , F[1] , ... ,F[nfft-1]
93  * Note that each element is complex and can be accessed like
94  f[k].r and f[k].i
95  * */
96 void kiss_fft(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout);
97 
98 /*
99  A more generic version of the above function. It reads its input from every Nth sample.
100  * */
101 void kiss_fft_stride(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,int fin_stride);
102 
103 /* If kiss_fft_alloc allocated a buffer, it is one contiguous
104  buffer and can be simply free()d when no longer needed*/
105 #define kiss_fft_free free
106 
107 /*
108  Cleans up some memory that gets managed internally. Not necessary to call, but it might clean up
109  your compiler output to call this before you exit.
110 */
111 void kiss_fft_cleanup(void);
112 
113 
114 /*
115  * Returns the smallest integer k, such that k>=n and k has only "fast" factors (2,3,5)
116  */
117 int kiss_fft_next_fast_size(int n);
118 
119 /* for real ffts, we need an even size */
120 #define kiss_fftr_next_fast_size_real(n) \
121  (kiss_fft_next_fast_size( ((n)+1)>>1)<<1)
122 
123 #ifdef __cplusplus
124 }
125 #endif
126 
127 #endif
kiss_fft_cpx::r
double r
real
Definition: kiss_fft.h:54
kiss_fft_cpx::i
double i
complex
Definition: kiss_fft.h:56
kiss_fft_state
kiss fft state
Definition: _kiss_fft_guts.h:29
kiss_fft_state::nfft
int nfft
nfft
Definition: _kiss_fft_guts.h:31
kiss_fft_cpx
kiss fft cpx
Definition: kiss_fft.h:52