SPLINE(CP) XENIX System V SPLINE(CP)
Name
spline - Interpolates smooth curve.
Syntax
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
has two continuous derivatives, and enough points to look
smooth when plotted.
The following options are recognized, each as a separate
argument.
-a Supplies 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
'' ' '' '
y0 = ky1 , . . . , yn = kyn-1
is set by the next argument. By default k = 0.
-n Spaces output points so that approximately n intervals
occur between the lower and upper x limits. (Default n
= 100.)
-p Makes output periodic, i.e. matches 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).
Diagnostics
When data is not strictly monotone in x, spline reproduces
the input without interpolating extra points.
Notes
A limit of 1000 input points is silently enforced.
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