NAME spline - interpolate smooth curve SYNOPSIS spline [ option ] ... DESCRIPTION Spline takes pairs of numbers from the standard input as abcissas and ordinates of a function. It produces a similar set, which is approximately equally spaced and includes the input set, on the standard output. The cubic spline output (R. W. Hamming, Numerical Methods for Scientists and Engi- neers, 2nd ed., 349ff) has two continuous derivatives, and sufficiently many points to look smooth when plotted, for example by plot (I). The following options are recognized, each as a separate argument. a Supply abscissas automatically (they are missing from the input); spacing is given by the next argument, or is assumed to be 1 if next argument is not a number. k The constant k used in the boundary value computation (2nd deriv. at end) = k*(2nd deriv. next to end) is set by the next argument. By default k = 0. n Space output points so that approximately n points occur between the lower and upper x limits. (Default n = 100.) p Make output periodic, i.e. match derivatives at ends. First and last input values should normally agree. x Next 1 (or 2) arguments are lower (and upper) x limits. Normally these limits are calculated from the data. Automatic abcissas start at lower limit (default 0). SEE ALSO plot (I) AUTHOR M. D. McIlroy BUGS A limit of 1000 input points is enforced silently. 1