// Some useful functions in gofft.

// Make a one-dimensional complex to complex forward transform
func FFT(x []complex128) []complex128

// Make a one-dimensional real to complex forward transform
func FFTReal(x []float64) []complex128

// Make a one-dimensional complex to complex inverse transform
// Note that a real to complex inverse transform exists, but a
// complex to real inverse transform does not -- the former is
// not very useful, so is not documented here
func IFFT(x []complex128) []complex128

// Make a two-dimensional complex to complex forward transform --
// note that the input and results are represented by unflattened
// two-dimensional slices -- the gocandis package has routines
// to flatten and unflatten 2, 3, and 4 dimensional slices
func FFT2(x [][]complex128) [][]complex128

// Make a two-dimensional real to complex forward transform
func FFT2Real(x [][]float64) [][]complex128

// Make a two-dimensional complex to complex inverse transform
func IFFT2(x [][]complex128) [][]complex128

// Make convolution of 2 one-dimensional complex slices --
// this uses FFT and IFFT
func Convolve(x, y []complex128) []complex128