
From:  David Bateman 
Subject:  Re: Voronoi Diagrams 
Date:  Mon, 29 Dec 2008 22:53:37 +0100 
Useragent:  MozillaThunderbird 2.0.0.17 (X11/20081018) 
Ryan Matthew Balfanz wrote:
That is a surprising result... It appears that Qhull's Voronoi algorithm has some sort of threshold of whether the distance between a point is considered significant or not that is relative to the distance between two points and the maximum distance between any point. Unfortunately the external box I added to get the matlab compatibiliy works well for convhull and needs to be extremely large in that case to approximate a box at infinite. However, it causes issues for voronoi. For now set scale to something smaller then 1e4 (say scale = 1e2) and it should work.. I'll look at a better fix soon.Hi All, I've changed the the lines starting from line number 127 to the following:  #idx = find (!infi); # Original idx = find ( ! resize (infi, size(c))); # Modified ll = length (idx); # Original #ll = min (length (idx), length (c)); # Modified  and get strange output. My input file can be found at http://www.phy.ilstu.edu/~rbalfanz/voronoi/inp.dat The output can be found at http://www.phy.ilstu.edu/~rbalfanz/voronoi/voronoi.pdf To get my results do the following in octave:  load inp.dat voronoi(inp(:,2), inp(:,3))  For the curious, columns 2 and 3 of inp.dat are positional data of galaxies. I'm having no trouble in MatLab working with this data even though individual points can be extremely close to one another.
D.  David Bateman address@hidden 35 rue Gambetta +33 1 46 04 02 18 (Home) 92100 BoulogneBillancourt FRANCE +33 6 72 01 06 33 (Mob)
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