g_fft_pow(G;S;O;X)
Returns the fast Fourier transform (FFT) power spectrum for each group
Syntax
g_fft_pow(G;S;O;X)
Input
Argument | Type | Description |
---|---|---|
G |
any | A space- or comma-separated list of column names Rows are in the same group
if their values for all of the columns listed in If If any of the columns listed in |
S |
integer | The name of a column in which every row evaluates to a 1 or 0, which determines
whether or not that row is selected to be included in the calculation If
If any of the values in
|
O |
integer | A space- or comma-separated list of column names that
determine the row order within a particular group If
If any of the values in |
X |
integer or decimal | A column name
|
Return Value
For every row in each group defined by G
(and for those rows where
S
=1, if specified), g_fft_pow
returns a decimal number corresponding to the power spectrum of the data computed using FFT
for each group.
Data to be Fourier-transformed should not contain any N/A. Any N/A in the data returns N/A as the result for the entire group.