phenofit (version 0.3.2)

v_curve: v_curve

Description

V-curve is used to optimize Whittaker parameter lambda. Update 20180605 add weights updating to whittaker lambda selecting

Usage

v_curve(INPUT, lg_lambdas, d = 2, IsPlot = FALSE, wFUN = wTSM, iters = 2)

Arguments

INPUT

A list object with the elements of t, y, w, Tn (optional) and ylu, returned by check_input().

lg_lambdas

lg lambda vectors of Whittaker parameter.

d

Difference order.

IsPlot

Boolean. Whether to plot figure?

wFUN

weights updating function, can be one of wTSM(), wChen(), wBisquare() and wSELF().

iters

How many times curve fitting is implemented.

Examples

data("CA_NS6"); d = CA_NS6

# global parameter
IsPlot = TRUE
nptperyear = 23

INPUT    <- check_input(d$t, d$y, d$w, nptperyear,
                        maxgap = nptperyear/4, alpha = 0.02, wmin = 0.2)
# INPUT$y0 <- d$y   # raw time-series, for visualization

lg_lambdas <- seq(0, 3, 0.1)
r <- v_curve(INPUT, lg_lambdas, d = 2, IsPlot = TRUE)