[SciPy-Dev] Scipy.spatial.Delaunay fail to produce the tetrahedron for all particles

Pauli Virtanen pav@iki...
Sun Sep 30 08:42:18 CDT 2012

Dear Ilaudy,

25.09.2012 11:57, Ilaudy kirjoitti:
> I am using Scipy.spatial.Delaunay to do some analysis. I found that the Delaunay
> model can not produce the tetrahedron for my simulated 3D particles which is at
> the center of a halo. Lots of it are not included in the tri.vertices. For
> example, I select about ~2300 particles in the center, and do the triangulation.
> But the tri.vertices only have a shape of (484, 4)! I think this should be a
> problem of the Hull's accuracy setting. Can I know where I can tune this? Or any
> suggestions are welcome.

Yes, this is an issue due to QHull not including some vertices in the
triangulation due to precision issues.

This can probably be avoided by supplying additional options to Qhull.
For instance, "QJ" should force it to produce a triangulation including
all points. Unfortunately, currently there's no way to pass custom
options to scipy.spatial.Delaunay, but adding that is in the plans.

Pauli Virtanen

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