TVec.FFT Method (boolean)

Fast Furier Transformation (FFT) from complex to complex or from real to complex.

Pascal

function FFT(ConjugateExtend: boolean = false): TVec; overload;

Fast Furier Transformation (FFT) from complex to complex or from real to complex. Calculate the FFT from all calling vector elements in-place. If the calling vector is complex then complex to complex forward FFT is performed. If the calling vector is real then real to complex FFT is performed.

The Length of the transforming vector can be any number but highest performance will be achieved if it is a power of two.

Notes

When performing FFT from real to complex the conjugated symmetric part is also generated by conjugating and mirroring the first half of the spectrum. If Complex is false, the operation will not be performed in-place, if the Length of the destination will allocate more than amount of the memory preallocated for the TVec object. Instead, the data will be copied first to allocate enough space to store the result.

There are two important parameters to consider that affect how will the FFT be computed: TDenseMtxVec.FFTStorageFormat and TDenseMtxVec.FFTScrambled. The default storage format is fsfCCS.

Example

var a,b: TVec; begin CreateIt(a,b); try a.SetIt(False,[1,2,3,4]); b.FFT(a); a.FFT; // a = [(10, 0),( -2,2), (-2, 0), (-2,-2)] if not a.Equal(b) then ERaise('Not equal'); finally FreeIt(a,b); end; end;

TVec Class, TVec Members, MtxVec Namespace, FFT Method, Example, See Also

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