spectr provides a consistent interface to use various methods to calculate the periodogram and estimate the period of a rhythmic time-course. Methods include Lomb-Scargle, fast Fourier transform, and three versions of the chi-square periodogram.


The risks of using the chi-square periodogram to estimate the period of biological rhythms, Tackenberg and Hughey, PLOS Comput Biol 2021

Optogenetic stimulation of VIPergic SCN neurons induces photoperiodic changes in the mammalian circadian clock, Tackenberg et al., bioRxiv