(num) This should be a numeric vector representing the process to estimate.
k
(int) The number of Gegenbauer frequencies
alpha
(num)
method
(char) One of "gsp" or "lpr" - lpr is the log-periodogram-regression technique, "gsp" is the Gaussian
semi-parametric technique. "lpr" is the default. Refer Arteche (1998).
min_freq
(num) The minimum frequency to search through for peaks - default 0.0.
max_freq
(num) The maximum frequency to search through for peaks - default 0.5.