FFT

struct PrepareFftBig{T, NUMDIMS, DIMS}

PrepareFftBig( size_fft::Unsigned, [T=BigFloat])

Immutable structure to operate fft transform, x is the type of non transformed data also called signal.

Arguments :

• size_fft::Integer : Number of values, must be a power of two
• [T=BigFloat | x::T ] : type of the values

Implementation

• size_fft : size of the signal
• tab_permut : permutation
• root_one : size order roots of one
• rootoneconj : conjugate of root_one

struct parameters

• T : type of Float
• NUMDIMS : Numbers of dimensions
• DIMS : tuple of dimensions

_reverse_num(num, pos)

function that reverse the order of the pos lowest bits

fftbig!(par, signal; flag_inv)