Arguments
argvals
a vector or matrix of covariates.
effect
predictor whose effect varies with respect to argvals.
E.g., if the effect of diagnosis varies with age, use
sf(age, effect = diagnosis). Similar to argument by in
s. k
number of B-spline basis functions.
norder
order of B-splines: the default, 4, gives cubic
B-splines.
pen.order
order of the penalty, i.e., of the derivative defining the
penalty.
range.basis
a numeric vector of length 2 defining the interval over
which the B-spline basis is created. If NULL, set to the range of the
variable.
knots
knots placement method for B-spline smoothing. The default,
"quantile", places the knots at equally spaced quantiles of the data;
"equispaced" gives equally spaced knots.