f_trend_poly: Data Transformation: Polynomial Linear Trend of Zoo Time Series
Description
Fits a polynomial linear model on each column of a zoo object using time as a predictor, and predicts the outcome to return the polynomial trend of the time series. This method is a useful alternative to f_trend_linear when the overall. trend of the time series does not follow a straight line.
Usage
f_trend_poly(x = NULL, degree = 2, center = TRUE, ...)
Value
zoo object
Arguments
x
(required, zoo object) Zoo time series object to transform.
degree
(optional, integer) Degree of the polynomial. Default: 2
center
(required, logical) If TRUE, the output is centered at zero. If FALSE, it is centered at the data mean. Default: TRUE
...
(optional, additional arguments) Ignored in this function.