[SciPy-Dev] Problem with N-dimensional interpolation using a new griddata function for N>=3

Robert Kern robert.kern@gmail....
Tue Sep 21 09:57:03 CDT 2010


On Tue, Sep 21, 2010 at 09:17, Adam Machnik <amachnik@gmail.com> wrote:
> Hello,
> I am concerned in the difference in triangulation. I think that on
> such a simple grid there should be no difference from qhull results.

What you call a "simple grid" is actually a degenerate set of points
for Delaunay triangulation. There are a a large number of valid
triangulations that satisfy the Delaunay condition. The way that qhull
deals with degeneracy is to randomly perturb the points. While perhaps
qhull should pick a consistent random seed in order to reproduce
whichever of the arbitrarily chosen triangulations to return in your
degenerate case, please be aware that interpolation using
triangulation is not going to work very well for your case. Trilinear
interpolation would be better.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
  -- Umberto Eco


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