CPU FFT API

CPU-based FFT fallback for environments without WebGPU, including real-input RFFT helpers.

Complex FFT APIs

cpuFFT()

Performs a 1D forward FFT on interleaved complex input.

function cpuFFT(data: Float32Array): Float32Array;

• Input: interleaved complex data [Re, Im, Re, Im, ...]
• Return: interleaved complex frequency-domain data

cpuIFFT()

Performs a 1D inverse FFT on interleaved complex input.

function cpuIFFT(data: Float32Array): Float32Array;

cpuFFT2D()

Performs a 2D forward FFT on interleaved complex input.

function cpuFFT2D(
  data: Float32Array,
  width: number,
  height: number
): Float32Array;

cpuIFFT2D()

Performs a 2D inverse FFT on interleaved complex input.

function cpuIFFT2D(
  data: Float32Array,
  width: number,
  height: number
): Float32Array;

Real-Input FFT APIs

cpuRFFT()

Performs a 1D FFT for real-valued samples and returns a compressed half-spectrum.

function cpuRFFT(data: Float32Array): Float32Array;

• Input: real-valued samples of length N
• Return: interleaved complex half-spectrum containing N / 2 + 1 bins

cpuIRFFT()

Restores a real-valued signal from a compressed half-spectrum.

function cpuIRFFT(data: Float32Array): Float32Array;

cpuRFFT2D()

Performs a 2D FFT for real-valued input data and returns height × (width / 2 + 1) compressed complex bins.

function cpuRFFT2D(
  data: Float32Array,
  width: number,
  height: number
): Float32Array;

cpuIRFFT2D()

Restores a real-valued 2D signal from the compressed real-input spectrum.

function cpuIRFFT2D(
  data: Float32Array,
  width: number,
  height: number
): Float32Array;

Validation Helpers

validateFFTInput()

Validates 1D complex FFT input and returns the transform size.

function validateFFTInput(data: Float32Array): number;

validateFFT2DInput()

Validates 2D complex FFT input dimensions.

function validateFFT2DInput(
  data: Float32Array,
  width: number,
  height: number
): void;

Notes

• CPU real-input APIs currently wrap the complex FFT implementation; they establish the public contract first rather than introducing a separate optimized kernel.
• Use these APIs as the fallback path in environments where createFFTEngine() is unavailable.

Related

• FFTEngine — GPU-accelerated FFT engine
• CPU Fallback — Architecture details