lmrob.Psi {robustbase} | R Documentation |
Compute Tukey's bi-square score (psi) function and its first derivative.
lmrob.Psi(x, cc, deriv = 0)
x |
numeric vector. |
cc |
tuning constant |
deriv |
integer in {0,1,2} specifying the order of the
derivative; the default, deriv = 0 computes the chi-function. |
a numeric vector of the same length as x
.
Matias Salibian-Barrera and Martin Maechler
op <- par(mfrow = 2:1, oma = c(0,0, 2, 0), mgp = c(1.5, 0.6, 0), mar= .1+c(3,4,3,2)) x <- seq(-5, 5, length = 201) cc <- 4.69 # as set by default in lmrob.control() plot. <- function(...) { plot(...); abline(h=0,v=0, col="gray", lty=3)} plot.(x, lmrob.Psi(x, cc), type = "l", col = 2) plot.(x, lmrob.Psi(x, cc, deriv = 1), type = "l", col = 2) mtext(sprintf("lmrob.Psi(x, c = %g, deriv), deriv = 0,1", cc), outer = TRUE, font = par("font.main"), cex = par("cex.main")) par(op)