Calculate alpha (relationship between MSD and normal diffusion)

Source: R/calculateAlpha.R

Alpha is the MSD exponent. Normal diffusion is alpha = 1. Subdiffusion is alpha < 1 and superdiffusion is alpha > 1. Input is a data matrix of msd curves. Output is mean of log2(alpha), one value for each trace. D, calculated from a fit of the first four data points, is also outputted. The method excludes the first four data points from the alpha calculation - may result in NAs if tracks are too short.

calculateAlpha(alphaMat, tstep)

Arguments

alphaMat

matrix of msd curves, each col is a track, each row is time lag (will contain NAs)

tstep

variable. Time step in seconds

Value

data frame