void spline (x, y, n, n1, s1, s2, xn, yn) SMOOTH.C Level 3
 
float *x, *y The input arrays.
int n The dimension of x and y
int n1 The number of smoothed points
float s1 The initial slope of the smoothed line. If you do not wish to specify the slope set s1 = 1.0e30f (the program will then set the initial second derivative to zero).
float s2 The final slope of the smoothed line. If you do not wish to specify the slope set s2 = 1.0e30f (the program will set the final second derivative to zero).
float *xn, *yn The output x and y arrays of dimension n1.
 
spline() provides smoothed two-dimensional linear values using a cubic spline routine. Space for the output arrays must be allocated before this routine is called.