Description Usage Arguments Value Examples
View source: R/data_transformations.R
This is a wrapper function for generating surrogate time series using several different null models.
See test_nonlinearity
for an example context for usage of this
function.
make_surrogate_shuffle()
creates surrogates by randomly
permuting the values of the original time series.
make_surrogate_ebisuzaki()
creates surrogates by
randomizing the phases of a Fourier transform, preserving the power
spectra of the null surrogates
make_surrogate_seasonal()
creates surrogates by
computing a mean seasonal trend of the specified period and shuffling the
residuals.
make_surrogate_twin()
creates surrogates using the twin-
surrogate method, with the option to preserve the phase for seasonal/
periodic data
1 2 3 4 5 6 7 8 9 10 11 12 | make_surrogate_data(ts, method = c("random_shuffle", "ebisuzaki",
"seasonal", "twin"), num_surr = 100, ...)
make_surrogate_shuffle(ts, num_surr = 100)
make_surrogate_ebisuzaki(ts, num_surr = 100)
make_surrogate_seasonal(ts, num_surr = 100, T_period = 12)
make_surrogate_twin(ts, num_surr = 1, dim = 1, tau = 1,
phase_lock = TRUE, T_period = 24, initial_point = "same_season",
...)
|
ts |
the original time series |
method |
which algorithm to use to generate surrogate data |
num_surr |
the number of null surrogates to generate |
... |
remaining arguments are passed on to the specific function to make surrogate time series of that type |
T_period |
the period of seasonality for seasonal surrogates (ignored for other methods) |
dim |
the embedding dimension for the state-space reconstruction, in which twins are identified |
tau |
the lag for the state-space reconstruction |
phase_lock |
whether twins have to occur at the same phase |
initial_point |
how to sample the initial point. If '"same_season"', then the initial point is chosen from the same phase in a different cycle, and the surrogate is not allowed to line up in both phase and cycle with the original time series. |
A matrix where each column is a separate surrogate with the same length as 'ts'.
1 2 3 4 5 6 7 8 9 10 11 | data("two_species_model")
ts <- two_species_model$x[1:200]
make_surrogate_data(ts, method = "ebisuzaki")
make_surrogate_shuffle(rnorm(100), 10)
make_surrogate_ebisuzaki(rnorm(100), 10)
make_surrogate_seasonal(rnorm(100) + sin(1:100 * pi / 6), 10)
make_surrogate_twin(rnorm(100, sd = 0.1) + sin(1:100 * pi / 6), 10)
|
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