What is the meaning of the coefficients returned with the CURFIT task?
These coefficients are described in the design document for the curfit math package, which is called by the curfit task. The document can be printed with the following command: cl> help math$curfit/doc/curfit.spc fi+ | lprint Sections 3.2 (algorithms) and 6 (references) are most useful. Note that curfit evaluates the spline explicitly, NOT with look-up tables; the algorithms section is out of date and the comments about look-up tables should be ignored. The references used when writing the cubic spline code are: (1) Carl de Boor, “A Practical Guide to Splines”, 1978, Springer-Verlag New York Inc. (2) P.M. Prenter, “Splines and Variational Methods”, 1975, John Wiley and Sons Inc. The curfit package uses the least squares cubic spline described in detail in Chapter 14 of reference (1). The actual spline functions are the cardinal-B splines appropriate for fitting data with uniformly spaced knots. The cubic splines can be represented in terms of derivatives as you mentioned or as polynomi
These coefficients are described in the design document for the curfit math package, which is called by the curfit task. The document can be printed with the following command: cl> help math$curfit/doc/curfit.spc fi+ | lprint Sections 3.2 (algorithms) and 6 (references) are most useful. Note that curfit evaluates the spline explicitly, NOT with look-up tables; the algorithms section is out of date and the comments about look-up tables should be ignored. The references used when writing the cubic spline code are: • Carl de Boor, Practical Guide to Splines, 1978, Springer-Verlag New York Inc. • P.M. Prenter, Splines and Variational Methods, 1975, John Wiley and Sons Inc. The curfit package uses the least squares cubic spline described in detail in Chapter 14 of reference (1). The actual spline functions are the cardinal-B splines appropriate for fitting data with uniformly spaced knots. The cubic splines can be represented in terms of derivatives as you mentioned or as polynomial coeffic
