

   DDeessiiggnn MMaattrriixx ffoorr BB--sspplliinneess

        splineDesign(knots, x, ord, derivs)
        spline.des(knots, x, ord, derivs)

   AArrgguummeennttss::

      knots: a numeric vector of knot positions with non-
             decreasing values.

          x: a numeric vector of values at which to evaluate
             the B-spline functions or derivatives. The values
             in `x' must be between `knots[ord]' and `knots[
             length(knots) + 1 - ord ]'.

        ord: a positive integer giving the order of the spline
             function.  This is the number of coefficients in
             each piecewise polynomial segment, thus a cubic
             spline has order 4.  Defaults to 4.

     derivs: an integer vector of the same length as `x' and
             with values between `0' and `ord - 1'.  The
             derivative of the given order is evaluated at the
             `x' positions.  Defaults to a vector of zeroes of
             the same length as `x'.

   DDeessccrriippttiioonn::

        Evaluate the design matrix for the B-splines defined by
        `knots' at the values in `x'.

   VVaalluuee::

        A matrix with `length( x )' rows and `length( knots ) -
        ord' columns.  The i'th row of the matrix contains the
        coefficients of the B-splines (or the indicated deriva-
        tive of the B-splines) defined by the `knot' vector and
        evaluated at the i'th value of `x'.  Each B-spline is
        defined by a set of `ord' successive knots so the total
        number of B-splines is `length(knots)-ord'.

   NNoottee::

        The older `spline.des' function takes the same argument
        but returns a list with several components including
        `knots', `ord', `derivs', and `design'.  The `design'
        component is the same as the value of the
        `splineDesign' function.

   AAuutthhoorr((ss))::

        Douglas Bates and Bill Venables

   EExxaammpplleess::

        splineDesign(knots = 1:10, x = 4:7)

