spline(1g) spline(1g)
Name
spline - interpolate smooth curve
Syntax
spline [option...]
Description
The command 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 has two continuous derivatives,
and a sufficient number of points to look smooth when plotted.
Options
The following options are recognized, each as a separate argument.
-a Supplies abcissa automatically and uses specified number (next argument) for spacing. Default is 1.
-k Sets the boundary constant to the specified value (next argument). By default k = 0. For example,
(2nd deriv. at end) = k*(2nd deriv. next to end)
-n Uses specified number (n) in calculating intervals between lower and upper limits. (Default n = 100.)
-p Periodically produces output (matches derivates at ends). First and last input values should normally agree.
-x Uses specified numbers (next arguments) as lower and upper limits. Normally these limits are calculated from the data. Automatic
abcissas start at lower limit (default 0).
Restrictions
A limit of 1000 input points is enforced silently.
Diagnostics
When data is not strictly monotone in x, reproduces the input without interpolating extra points.
See Also
graph(1g), plot(1g)
spline(1g)
