Pspline by Jim Ramsay, 1996/11/26
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smooth.Pspline           Fit a polynomial smoothing spline of arbitrary
                         order
This has lines(), plot(), predict() and print() methods.

sm.spline                Interface to smooth.Pspline like smooth.spline

As smooth.Pspline requires x to be supplied in increasing order with no
ties, sm.spline tries to convert the data to that form and to select method
automatically.

B.D. Ripley 1998-08-23, 2013-03-01

