spline(C) 19 June 1992 spline(C) Name spline - interpolate smooth curve Syntax spline [ option ] ... 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 stan- dard 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 n 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 n The constant n used in the boundary value computation '' ' '' ' y0 = ky1 ,..., yn = kyn-1 is set by the next argument. By default n = 0. -n n Spaces output points so that approximately n intervals occur between the lower and upper x limits. (Default n = 100.) -p Makes output periodic, that is, matches derivatives at ends. First and last input values should normally agree. -x l [ u ] Next 1 (or 2) arguments are lower (and upper) x limits. Nor- mally these limits are calculated from the data. Automatic abscissas start at lower limit (default 0). Diagnostics When data is not strictly monotone in x, spline reproduces the input without interpolating extra points. Note A limit of 1000 input points is silently enforced.