Degrees of freedom in the smoothing spline fit in a GAM formula

0
votes

If the smoothing spline is simply a natural cubic spline with knots at every unique value of x_i. Then why does gam::s() in R need a degree of freedom?

1
rsplinesmoothinggamcubic-spline

1 Answers

2
votes

Because it is smoothing not interpolation. The degree of freedom tells how much complexity you want in the fitted spline.