Volume of convex hulls from Delaunay triangulation
Are there any known edge or degenerate cases with the simplex volume calculation in scipy.spatial's test_qhull.py (1)? Applying this method to my dataset, some of the volumes are negative and some are positive, which might just be the 3D analogue of area with a different surface normal. The goal is to get the total volume of the convex hull, which I assume I can just do by summing the absolute values of the individual simplex volumes. (1) https://github.com/scipy/scipy/blob/master/scipy/spatial/tests/test_qhull.py... Thanks, Eric
Eric Bruning <eric.bruning <at> gmail.com> writes:
Are there any known edge or degenerate cases with the simplex volume calculation in scipy.spatial's test_qhull.py (1)? Applying this method to my dataset, some of the volumes are negative and some are positive, which might just be the 3D analogue of area with a different surface normal.
The formula needs to be divided by ndim! to get the volume, cf., http://en.wikipedia.org/wiki/Simplex#Geometric_properties The volume is indeed oriented, and abs() gives the actual volume. I don't see any significant numerical caveats in the intended volume calculation using this approach. -- Pauli Virtanen
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Eric Bruning -
Pauli Virtanen