R: Specifying a smooth long term trend within a 'modTempEff'...
seas
R Documentation
Specifying a smooth long term trend within a ‘modTempEff’ model
Description
Function employed within the tempeff formula to specify the variable with a smooth effect.
The function does not fit the model, it simply returns information exploited by tempeff.
Usage
seas(x, ndx = stop("please, provide `ndx' in seas()"))
Arguments
x
the long term trend variable
ndx
the apparent dimension (i.e. the rank) of the B-spline employed to
model the long trend. For instance it could be min(40,n/4) where n is the
time series length.
Details
The function is used within the formula of tempeff() when the long term trend of the daily time series
is fitted via a smooth term. A standard P-spline with a cubic B-spline basis and a second-order
difference penalty is employed.
Value
A list with relevant information.
Author(s)
Vito Muggeo
References
Eilers, P., Marx, B. (1996). Flexible Smoothing with B-splines and Penalties
Statistical Science11, 89–121.
Wood, S.N. (2006) Generalized Additive Models: An Introduction with R.
Chapman and Hall/CRC Press.