Description: Potential Analysis

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Description

livpotential_ews performs one-dimensional potential estimation derived from a uni-variate timeseries

Usage

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  livpotential_ews(x, std = 1, bw = -1, xi = NULL,
    weights = c(), grid.size = 200)

Arguments

x

data vector

std

the standard deviation of the noise (defaults to 1, so then you use scaled potentials

bw

bandwidth for kernel estimation

xi

x values at which the potential is estimated

weights

optional weights in ksdensity (used by movpotentials).

grid.size

grid size

Details

see ref below

Value

livpotential returns a list with the following elements:

xi

the grid of points on which the potential is estimated

pot

the actual value of the potential

minima

the grid points at which the potential has minimum values

maxima

the grid points at which the potential has maximum values

bw

bandwidth of kernel used

Author(s)

Based on Matlab code from Egbert van Nes modified by Leo Lahti. Implemented in early warnings package by V. Dakos.

References

Livina, VN, F Kwasniok, and TM Lenton, 2010. Potential analysis reveals changing number of climate states during the last 60 kyr . Climate of the Past, 6, 77-82.

Dakos, V., et al (2012)."Methods for Detecting Early Warnings of Critical Transitions in Time Series Illustrated Using Simulated Ecological Data." PLoS ONE 7(7): e41010. doi:10.1371/journal.pone.0041010

See Also

generic_ews; ddjnonparam_ews; bdstest_ews; sensitivity_ews;surrogates_ews; ch_ews;movpotential_ews