ArrayFire: fft2 (original) (raw)
Fast Fourier Transform. More...
| Functions | |
|---|---|
| AFAPI array | fft2Norm (const array &in, const double norm_factor, const dim_t odim0=0, const dim_t odim1=0) |
| C++ Interface for fast fourier transform on two dimensional signals. More... | |
| AFAPI void | fft2InPlace (array &in, const double norm_factor=1.0) |
| C++ Interface for fast fourier transform on two dimensional signals. More... | |
| AFAPI array | fft2 (const array &in, const dim_t odim0=0, const dim_t odim1=0) |
| C++ Interface for fast fourier transform on two dimensional signals. More... | |
| AFAPI af_err | af_fft2 (af_array *out, const af_array in, const double norm_factor, const dim_t odim0, const dim_t odim1) |
| C Interface for fast fourier transform on two dimensional signals. More... | |
| AFAPI af_err | af_fft2_inplace (af_array in, const double norm_factor) |
| C Interface for fast fourier transform on two dimensional signals. More... | |
Fast Fourier Transform.
The Fast Fourier Transform (FFT) is an efficient algorithm to compute the discrete Fourier transform (DFT) of a signal or array. This is most commonly used to convert data in the time (or space) domain to the frequency domain, Then, the inverse FFT (iFFT) is used to return the data to the original domain.
There are numerous algorithms to compute the FFT of an array, and the specifics of the algorithm depend on the target hardware. Most algorithms, however, use a Cooley-Tukey scheme in a divide-and-conquer approach.
Note
There are some convenience functions provided for fft where normalization factor is not required as input paramter. In such cases, the normalization factor is calculated internally based on the input data provided.
◆ af_fft2()
C Interface for fast fourier transform on two dimensional signals.
Parameters
| [out] | out | is the transformed array |
|---|---|---|
| [in] | in | is the input array |
| [in] | norm_factor | is the normalization factor with which the input is scaled after the transformation is applied |
| [in] | odim0 | is the length of output signals along first dimension - used to either truncate/pad the input |
| [in] | odim1 | is the length of output signals along second dimension - used to either truncate/pad the input |
Returns
AF_SUCCESS if the fft transform is successful, otherwise an appropriate error code is returned.
◆ af_fft2_inplace()
C Interface for fast fourier transform on two dimensional signals.
Parameters
| [in,out] | in | is the input array on entry and the output of 2D forward fourier transform on exit |
|---|---|---|
| [in] | norm_factor | is the normalization factor with which the input is scaled after the transformation is applied |
Returns
AF_SUCCESS if the fft transform is successful, otherwise an appropriate error code is returned.
Note
The input in must be a complex array
C++ Interface for fast fourier transform on two dimensional signals.
This version of fft function uses a default norm_factor parameter that is calculated internally based on the input signals.
Parameters
| [in] | in | is the input array |
|---|---|---|
| [in] | odim0 | is the length of output signals along first dimension - used to either truncate/pad the input |
| [in] | odim1 | is the length of output signals along second dimension - used to either truncate/pad the input |
Returns
the transformed array
◆ fft2InPlace()
| AFAPI void fft2InPlace | ( | array & | in, |
|---|---|---|---|
| const double | norm_factor = 1.0 | ||
| ) |
C++ Interface for fast fourier transform on two dimensional signals.
Parameters
| [in,out] | in | is the input array on entry and the output of 2D forward fourier transform on exit |
|---|---|---|
| [in] | norm_factor | is the normalization factor with which the input is scaled after the transformation is applied |
Note
The input in must be complex
◆ fft2Norm()
C++ Interface for fast fourier transform on two dimensional signals.
Parameters
| [in] | in | is the input array |
|---|---|---|
| [in] | norm_factor | is the normalization factor with which the input is scaled after the transformation is applied |
| [in] | odim0 | is the length of output signals along first dimension - used to either truncate/pad the input |
| [in] | odim1 | is the length of output signals along second dimension - used to either truncate/pad the input |
Returns
the transformed array