Generate the spline basis matrix for non log-linear effect.
NLL(x,
Spline = c("b-spline", "tp-spline", "tpi-spline"),
Knots = NULL,
Degree = 3,
Intercept = FALSE,
Boundary.knots = range(x),
Keep.duplicates = TRUE,
outer.ok = TRUE,
...)
the predictor variable.
a character string specifying the type of spline basis. "b-spline" for B-spline basis, "tp-spline" for truncated power basis and "tpi-spline" for monotone (increasing) truncated power basis.
the internal breakpoints that define the spline used to estimate the NLL effect. By default there are none.
degree of splines which are considered.
a logical value indicating whether intercept/first basis of spline should be considered.
range of variable which is analysed.
Should duplicate interior knots be kept or removed. Defaults is FALSE
, which removes
duplicate knots with a warning if duplicate interior knots are found.
logical indicating how are managed x
values outside the knots. If FALSE
,
return NA
, if TRUE
, return 0
for the corresponding x
values.
not used
NLL
is based on package orthogonalsplinebasis
NPH
and
NPHNLL
.