# periodogram_methods: Methods For Computing Periodograms In rethomics/zeitgebr: Analysis of Circadian Behaviours

## Description

These functions provides a series of methods to assess periodicity of circadian processes.

## Usage

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16``` ```ac_periodogram(x, period_range = c(hours(16), hours(32)), sampling_rate = 1/mins(1), alpha = 0.05) chi_sq_periodogram(x, period_range = c(hours(16), hours(32)), sampling_rate = 1/mins(1), alpha = 0.05, time_resolution = hours(0.1)) cwt_periodogram(x, period_range = c(hours(16), hours(32)), sampling_rate = 1/mins(1), alpha = 0.05, resolution = 1/512, n_sim = 10) fourier_periodogram(x, period_range = c(hours(16), hours(32)), sampling_rate = 1/mins(1), alpha = 0.05) ls_periodogram(x, period_range = c(hours(16), hours(32)), sampling_rate = 1/mins(1), alpha = 0.05, oversampling = 8) ```

## Arguments

 `x` numeric vector `period_range` vector of size 2 defining minimal and maximal range of period to study (in seconds) `sampling_rate` the – implicitly regular – sampling rate of x (in hertz) `alpha` significance level `time_resolution` the resolution of periods to scan `resolution` the period resolution of the CWT (i.e. the number of suboctaves) `n_sim` the number of shuffling simulation to compute p-value (see WaveletComp::analyze.wavelet) `oversampling` the oversampling factor (see lomb::lsp)

## Value

a data.table with the columns:

• `period` – the period (in s)

• `power` – the power (or equivalent) for a given period

• `p_value` – the significance of the power

• `signif_threshold` – the significance threshold of the power (at alpha)

## References

• lomb::lsp – the orginal function for `ls_periodogram`
• stats::acf – the orginal function for `ac_periodogram`
• WaveletComp::analyze.wavelet – the orginal function for `cwt_periodogram`