FFTInitializeUnityTable

Initializes unity roots lookup table used by Fast Fourier Transform functions.

Syntax

void FFTInitializeUnityTable(
         XMVECTOR __restrict *pUnityTable,
         size_t uLength
)

Parameters

pUnityTable
Type: XMVECTOR __restrict *

[out] Caller-provided array of XMVECTOR elements that will be populated with the unity table values. The array passed to pUnityTable must be at least uLength elements long.

uLength
Type: size_t

[in] The FFT length in frames (sample count / channel count). uLength must be a power of two and must be greater than 16.

Return value

Type: void

None.

Remarks

Once initialized, the table does not need to be initialized again unless you want a different FFT length.

Unity tables for FFT lengths of 16 and below are hard coded into the respective FFT functions (FFT16, FFT8, and FFT4). They do not need to be initialized.

All buffer parameters must be 16-byte aligned. Audio data must be FLOAT32 mono.

Requirements

Header: Declared in XDSP.h.