Description Usage Arguments Details Note Author(s) References Examples
This function determines the minimum embedding dimension from a scalar time series using the algorithm proposed by L. Cao (see references).
1 2 3 4 | estimateEmbeddingDim(time.series,
number.points = length(time.series), time.lag = 1,
max.embedding.dim = 15, threshold = 0.95,
do.plot = TRUE, theiler.window = 1)
|
time.series |
The original time series. |
number.points |
Number of points from the time series that will be used to estimate the embedding dimension. By default, all the points in the time series are used. |
time.lag |
Time lag used to build the Takens' vectors needed to estimate the embedding dimension (see buildTakens). Default: 1. |
max.embedding.dim |
Maximum possible embedding dimension for the time series. Default: 15. |
threshold |
Numerical value between 0 and 1. The embedding dimension is estimated using the E1(d) function. E1(d) stops changing when d is greater than or equal to embedding dimension, staying close to 1. This value establishes a threshold for considering that E1(d) has stopped to change. Default: 0.95 |
do.plot |
Logical value. If TRUE (default value), a plot of E1(d) and E2(d) is shown. |
theiler.window |
Integer denoting the Theiler window: Two Takens' vectors must be separated by more than theiler.window time steps in order to be considered neighbours. By using a Theiler window, we exclude temporally correlated vectors from our estimations. Default: 1. |
The Cao's algorithm uses 2 functions in order to estimate the embedding dimension from a time series: the E1(d) and the E2(d) functions, where d denotes the dimension.
E1(d) stops changing when d is greater than or equal to the embedding dimension, staying close to 1. On the other hand, E2(d) is used to distinguish deterministic signals from stochastic signals. For deterministic signals, there exist some d such that E2(d)!=1. For stochastic signals, E2(d) is approximately 1 for all the values.
The current implementation of this function is fully written in R (as a prototype). Thus it requires heavy computations and may be quite slow. Future versions of the package will solve this issue.
In the current version of the package, the automatic detection of stochastic signals has not been implemented yet.
Constantino A. Garcia
Cao, L. Practical method for determining the minimum embedding dimension of a scalar time series. Physica D: Nonlinear Phenomena, 110,1, pp. 43-50 (1997).
1 2 3 4 5 6 | ## Not run:
h = henon(do.plot=FALSE)
dimension = estimateEmbeddingDim(h$x, time.lag=1, max.embedding.dim=6,
theiler.window=10, threshold=0.9, do.plot=TRUE)
## End(Not run)
|
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