cSplineDes               package:mgcv               R Documentation

Evaluate cyclic B spline basis

Description:

     Uses 'splineDesign' to set up the model matrix for a cyclic
     B-spline basis.

Usage:

     cSplineDes(x, knots, ord = 4)

Arguments:

       x: covariate values for smooth.

   knots: The knot locations: the range of these must include all the
          data.

     ord: order of the basis. 4 is a cubic spline basis. Must be >1.

Details:

     The routine is a wrapper that sets up a B-spline basis, where the
     basis functions wrap at the first and  last knot locations.

Value:

     A matrix with 'length(x)' rows and 'length(knots)-1' columns.

Author(s):

     Simon N. Wood simon.wood@r-project.org

See Also:

     'cyclic.p.spline'

Examples:

      x <- 0:100/100;k<- 0:5/5
      X <- cSplineDes(x,k)
      plot(x,X[,1],type="l"); for (i in 2:5) lines(x,X[,i],col=i)

