bs {lazy.stat}

R Documentation

Generate B Spline Basis

Description

Generate B Spline Basis

Usage

bs(
  x,
  nknots = 0,
  knots = NULL,
  intercept = TRUE,
  xmin = NULL,
  xmax = NULL,
  boundary.knots = NULL,
  degree = 3,
  xlim = NULL,
  ylim = NULL,
  title = "b-spline",
  print = 0,
  plot = 0
)

Arguments

x	Input vector.
nknots	# of knots to be used in [xmin, xmax].
knots	vector consisting of (internal) knots to be used.
intercept	= 0 to omit the intercept.
xmin	minimum of internal knots.
xmax	maximum of internal knots.
boundary.knots	Boundary knots.
degree	Degree of polynomial to be used.
xlim	xlim for plot.
ylim	ylim for plot.
title	Plot title.
print	= 1 to print the result.
plot	= 1 to plot the result.

Details

When knots are present, it has priority over nknots.
Default value of the boundary.knots is c(min(temp),max(temp))
where temp=c(x,interior.knots).

Value

List of:
x
X=length(x) x (nknots+degree+1) spline basis matrix
type="b"
knots ( boundary + inside )
interior.knots, boundary.knots, degree, nknots

Examples

n <- 100
x <- seq(-1,1, length=n)
bs( x, nknots=2, plot=1 )

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