Computes the B-spline basis matrix for a given polynomial spline.
bscpp(
x = NA_real_,
df = NA_integer_,
knots = NA_real_,
degree = 3L,
intercept = 0L,
boundary_knots = NA_real_,
warn_outside = 1L
)A matrix with dimensions c(length(x), df). If
df is provided, the matrix will have df columns.
Alternatively, if knots are supplied, the number of columns
will be length(knots) + degree + intercept. The matrix
contains attributes that correspond to the arguments
passed to the bscpp function.
A numeric vector representing the predictor variable.
Degrees of freedom, specifying the number of columns in the
basis matrix. If df is provided, the function automatically
selects df - degree - intercept internal knots based on
appropriate quantiles of x, ignoring any missing values.
A numeric vector specifying the internal breakpoints
that define the spline. If not provided, df must be specified.
An integer specifying the degree of the piecewise
polynomial. The default value is 3, which corresponds to
cubic splines.
A logical value indicating whether to include an
intercept in the basis. The default is FALSE.
A numeric vector of length 2 specifying the
boundary points where the B-spline basis should be anchored.
If not supplied, the default is the range of non-missing values
in x.
A logical value indicating whether a warning
should be issued if any values of x fall outside the
specified boundary knots.
Kaifeng Lu, kaifenglu@gmail.com