Re: [Help-gsl] monotone interpolation

[Feng Chen]

How about this one? (The green curve does not look like monotonic to me
though ... The blue curve is the reference you cited)

MESA/INTERP_1D
monotonicity preserving cubic interpolation
piecewise monotonic cubic interpolation

http://mesa.sourceforge.net/interp_1D.html


On Thu, Mar 1, 2012 at 1:30 PM, Christian Krueger <address@hidden>
wrote:
>
> Hi... is there any possibility to get a strictly monotone interpolation
function?
>
> I have data which for sure have to be monotone, but the provided
interpolation methods (cspline, akima) do not preserve this condition
(linear interpolation is not smooth and polynomial of course useless with
200+ datapoints).
>
> I wonder whether the method of Steffen (1990) is implemented somewhere
which seem to have some nice features (monotonicity, almost no spurious
oscillations)? Or might it be a useful extension for GSL?
> Found in this paper: A simple method for monotonic interpolation in one
dimension, Astron. Astrophys. 239, 443 (1990)
>
>
> Regards,
> Christian
>