ANTsR (version 0.3.3)

alffmap: alffmap

Description

Amplitude of Low Frequency Fluctuations (ALFF; Zang et al., 2007) and fractional Amplitude of Low Frequency Fluctuations (f/ALFF; Zou et al., 2008) are related measures that quantify the amplitude of low frequency oscillations (LFOs). This function outputs ALFF and fALFF for the input.

Usage

alffmap(x, flo = 0.01, fhi = 0.1, tr = 1, detrend = TRUE, takesqrt = FALSE)

Arguments

x

input vector for the time series of interest

flo

low frequency, typically 0.01

fhi

high frequency, typically 0.1

tr

the period associated with the vector x (inverse of frequency)

detrend

detrend the input time series

takesqrt

take the sqrt of the computed values

Value

vector is output showing ALFF and fALFF values

Examples

mat <- matrix(rnorm(3000),ncol=50)
fallf = apply( mat, FUN=alffmap, MARGIN=2 )