Get basis for an illustration of an M-spline with given knots.

Get basis for an illustration of an M-spline with given knots.

Usage

mspline_plotsetup(
  knots,
  bknot = 10,
  tmin = NULL,
  tmax = NULL,
  degree = 3,
  df = 10,
  bsmooth = TRUE
)

Arguments

knots

Vector of knot locations. If not supplied, df has to be specified. One of two rules is then used to choose the knot locations. If bknots is specified, a set of equally spaced knots between zero and bknots is used. Otherwise if obstimes is supplied, the knots are chosen as equally spaced quantiles of obstimes.

The number of knots (excluding zero) is df - degree + 1 if bsmooth is TRUE, or df - degree - 1 otherwise.

bknot

Location of the final spline knot.

tmin

Minimum plotting time. Defaults to zero.

tmax

Maximum plotting time. Defaults to the highest knot.

degree

Spline polynomial degree. Can only be changed from the default of 3 if bsmooth is FALSE.

df

Desired number of basis terms, or "degrees of freedom" in the spline. If knots is not supplied, the number of knots is then chosen to satisfy this.

bsmooth

If TRUE then the function is constrained to also have zero derivative and second derivative at the boundary.

Value

Data frame containing the basis, as returned by mspline_basis.