vsip_ccfftip_create_p - Create FFT Object (In-Place)

Core

This manual is preliminary and incomplete.
While our Core implementation implements all functions given in the standard we are still working on completing this documentation.

Please refer to the VSIPL standard for a complete function reference of the Core profile until we have completed work on this documentation.

[next] [prev] [prev-tail] [tail] [up]

5.1.2 vsip_ccfftip_create_p - Create FFT Object (In-Place)

typedef enum _vsip_fft_dir { 
    VSIP_FFT_FWD = -1, 
    VSIP_FFT_INV = +1 
} vsip_fft_dir; 
 
typedef enum _vsip_alg_hint { 
  VSIP_ALG_TIME  = 0, 
  VSIP_ALG_SPACE = 1, 
  VSIP_ALG_NOISE = 2 
} vsip_alg_hint; 
 
 
vsip_fft_f* vsip_ccfftip_create_f(vsip_length length, vsip_scalar_f scale, 
                                  vsip_fft_dir sign, vsip_length ntimes, 
                                  vsip_alg_hint hint);

Description

These functions create FFT (Fast Fourier Transform) object for a complex-to-complex in-place FFT. The functions initialize a FFT object with the specified length, scale factor, direction, number of times to apply the FFT, and algorithm hint.

The performance for supported FFT sizes is standardized as $O(nlogn)$ . For sizes not directly supported by the FFT kernels a DFT fallback with a performance of $2 O(n )$ is standardized.

Parameters

vsip_length length: The length of the FFT.
vsip_scalar_f scale: The scale factor to apply to the FFT result.
vsip_fft_dir sign: The direction of the FFT.
- VSIP_FFT_FWD - Forward
- VSIP_FFT_INV - Inverse
vsip_length ntimes: The number of times to apply the FFT.
vsip_alg_hint hint: Algorithm hint for the FFT.
- VSIP_ALG_TIME - Optimize for time
- VSIP_ALG_SPACE - Optimize for memory usage
- VSIP_ALG_NOISE - Optimize for noise

Return Value

On success, a pointer to the newly created FFT object is returned.
On error, NULL is returned.

Example

vsip_length length = 1024; 
vsip_scalar_f scale = 1.0; 
vsip_fft_dir direction = VSIP_FFT_FWD; // Forward FFT 
vsip_length ntimes = 1; 
vsip_alg_hint hint = VSIP_ALG_TIME; 
 
vsip_fft_f *fft_cc; 
vsip_fft_f *fft_rc; 
vsip_fft_f *fft_cr; 
 
// Create complex-to-complex FFT object 
fft_cc = vsip_ccfftip_create_f(length, scale, direction, ntimes, hint); 
if (fft_cc == NULL) { 
    // Handle error 
}

[next] [prev] [prev-tail] [front] [up]