SPLINE(1G)                           SysV                           SPLINE(1G)



NAME
     spline - interpolate smooth curve

SYNOPSIS
     spline [ options ]

DESCRIPTION
     spline takes pairs of numbers from the standard input as abscissas 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
     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:
               y'' = ky'',    y'' = ky''
          is set0by the1next arg
nument (
n-
d1
efault 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 abscissas
          start at lower limit (default 0).

SEE ALSO
     graph(1G).

DIAGNOSTICS
     When data is not strictly monotone in x, spline reproduces the input
     without interpolating extra points.

BUGS
     A limit of 1,000 input points is enforced silently.