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INVFFT

Syntax: INVFFT(R)

R = a range

INVFFT generates the inverse Discrete Fourier Transform or range R using a Fast Fourier Transform algorithm. The length of the vector must be a power of 2. INVFFT will produce the same results as INVDFT, but it is much faster ($N \log N$) time as opposed to $N^2$ time).

Examples:

Matrix A1..B4 =

  A B
1 0.99 0
2 3 6.2
3 4.1 1.1
4 3.3 6.3
     

INVFFT(A1..B4) =
2.8475 3.4
-0.8025 -0.2
-0.3025 -2.85
-0.7525 -0.35

INVFFT(A1..F3) = Error - INVFFT, dimension must be power of 2

Excel function: N/A


next up previous contents index
Next: IPMT, XLIPMT Up: A. Function Reference Previous: INVERT   Contents   Index
SpreadScript User's Guide, Version 1.2
Grey Trout Software
02 March 2003