SPLINE(1) | User's Reference Manual | SPLINE(1) |
aspline - Akima spline interpolation
aspline [-a xstep] [-l llim] [-u ulim] [-n n] {file(s)}
aspline reads pairs of numbers from the indicated file(s) (or from stdin if no files were given) as abscissas and ordinates of a function. It produces a similar set, which is approximately equally spaced and includes the input set on standard output. The output is an Akima-interpolated spline which has an continuous first derivative. The second derivate may be discontinuous, but the output does not wiggle as it would do with cubic splines.
Datasets are separated by blank lines.
H. Akima, A New Method of Interpolation and Smooth Curve Fitting Based on Local Procedures, Journal of Assc. for Comp. Mach., Vol. 17, No. 4, Oct. 1970, pp. 589—602
If you need a continuous second derivative, use spline from the plotutils package instead.
January 1998 | Debian |