ANTsR (version 0.7.2.0)

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, kernel)

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

kernel

smoothing kernel in estimate, see spec.pgram

Value

vector is output showing ALFF and fALFF values

Examples

# NOT RUN {
mat <- matrix(rnorm(3000),ncol=50)
fallf = apply( mat, FUN=alffmap, MARGIN=2 )
k = kernel("daniell", rep( 2, 3 ) )
fallf2 = apply( mat, FUN=alffmap, MARGIN=2, kernel=k )

# }