lf()

lf {locfit} R Documentation
Locfit term in Additive Model formula
Description
This function is used to specify a smooth term in a gam() model formula.
This function is designed to be used with the S-Plus gam() function. For R users, there are at least two different gam() functions available. Most current distributions of R will include the mgcv library by Simon Wood; lf() is not compatable with this function.
On CRAN, there is a gam package by Trevor Hastie, similar to the S-Plus version. lf() should be compatable with this, although it's untested.
Usage
lf(..., alpha=0.7, deg=2, scale=1, kern="tcub", ev=rbox(), maxk=100)
Arguments
...
numeric predictor variable(s)
alpha, deg, scale, kern, ev, maxk
these are as in locfit.raw.
See Also
locfit, locfit.raw, gam.lf, gam
Examples
# fit an additive semiparametric model to the ethanol data.
stopifnot(require(gam))
# The `gam' package must be attached _before_ `locfit', otherwise
# the following will not work.
data(ethanol, package = "lattice")
fit <- gam(NOx ~ lf(E) + C, data=ethanol)
op <- par(mfrow=c(2, 1))
plot(fit)
par(op)
[Package lo