make_surrogate_data {rEDM} | R Documentation |
make_surrogate_data
generates surrogate data under several different
null models.
make_surrogate_data(ts, method = c("random_shuffle", "ebisuzaki", "seasonal"), num_surr = 100, T_period = 1)
ts |
the original time series |
method |
which algorithm to use to generate surrogate data |
num_surr |
the number of null surrogates to generate |
T_period |
the period of seasonality for seasonal surrogates (ignored for other methods) |
Method "random_shuffle" creates surrogates by randomly permuting the values of the original time series.
Method "Ebisuzaki" creates surrogates by randomizing the phases of a Fourier transform, preserving the power spectra of the null surrogates.
Method "seasonal" creates surrogates by computing a mean seasonal trend of the specified period and shuffling the residuals.
See test_nonlinearity
for context.
A matrix where each column is a separate surrogate with the same length as ts
.
data("two_species_model") ts <- two_species_model$x[1:200] make_surrogate_data(ts, method = "ebisuzaki")