SPLINE(1G)SPLINE(1G)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 Engineers, 2nd ed., 349ff) has two
continuous derivatives, and sufficiently many points to look smooth
when plotted, for example by graph(1G).
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 intervals 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 ALSOgraph(1G), plot(1G)DIAGNOSTICS
When data is not strictly monotone in x, spline reproduces the input
without interpolating extra points.
BUGS
A limit of 1000 input points is enforced silently.
7th Edition April 29, 1985 SPLINE(1G)
