Re: [Bug-gsl] DIFF in CSPLINE Interpolation bug !?

[Rhys Ulerich]

> I did a test of CSPLINE interpolation from the GSL package and compared the
> test (interp.c) file given in the doc/examples/ directory of the native GSL
> package
> to the XMGRACE interpolation function and found that they differ
> significantly.
> here i attach a pdf file which shows this difference.

What does XMGRACE use for end conditions on the cspline?  I notice
from your PDF that the discrepancies seem to "originate" in the
derivatives at the ends of the interval.  GSL's end conditions are
documented here:
http://www.gnu.org/software/gsl/manual/html_node/Interpolation-Types.html#Interpolation-Types

- Rhys