plgraphics (version 1.2)

smoothRegr: Smoothing function used as a default in plgraphics / straight line "smoother"

Description

These functions wrap the loess smoothing function or the lm.fit function in order to meet the argument conventions used in the plgraphics package.

Usage

smoothRegr(x, y, weights = NULL, par = NULL, iterations = 50, minobs=NULL, ...)
smoothLm(x, y, weights = NULL, ...)

Value

vector of smoothed values, with an attribute xtrim, which is 1 for smoothRegr and 0 for smoothLm. If loess fails, NAs will be returned without issuing a warning.

Arguments

x

vector of x values

y

vector of y values to be smoothed

weights

vector of weigths used for fitting the smooth

par

value for the span argument of loess.

iterations

number of iterations for the loess algorithm. If ==1, the non-robust, least squares version is applied.

minobs

minimal number of observations. If less valid observations are provided, the result is NULL.

...

Further arguments, passed to loess.

Author

Werner A. Stahel, ETH Zurich

See Also

loess, gensmooth

Examples

t.x <- (1:50)^1.5
t.y <- log10(t.x) + rnorm(length(t.x),0,0.3)
t.y[40] <- 5
r.sm <- smoothRegr(t.x, t.y, par=0.5)
r.sm1 <- smoothRegr(t.x, t.y, iterations=1, par=0.5)

plot(t.x,t.y)
lines(t.x,r.sm, col=2)
lines(t.x,r.sm1, col=3)