SPLINE(1G)           INTERACTIVE UNIX System           SPLINE(1G)



          NAME
               spline - interpolate smooth curve

          SYNOPSIS
               spline [ options ]

          DESCRIPTION
               The spline command 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 sufficient
               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:

                    tdefine prime2 'sup down 20 ''' ndefine prime2 'sup '''
                    y sub 0 prime2 ~=~ ky sub 1 prime2 , ~~~~ y sub n
                    prime2 ~=~ ky sub n-1 prime2

               is set by the next argument (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 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.





          Rev. Base System                                           Page 1