A comparison of period finding algorithms

This paper presents a comparison of popular period finding algorithms applied to the light curves of variable stars from the Catalina Real-Time Transient Survey, MACHO and ASAS data sets. We analyse the accuracy of the methods against magnitude, sampling rates, quoted period, quality measures (signal-to-noise and number of observations), variability and object classes. We find that measure of dispersion-based techniques - analysis of variance with harmonics and conditional entropy - consistently give the best results but there are clear dependences on object class and light-curve quality. Period aliasing and identifying a period harmonic also remain significant issues. We consider the performance of the algorithms and show that a new conditional entropy-based algorithm is the most optimal in terms of completeness and speed. We also consider a simple ensemble approach and find that it performs no better than individual algorithms.