Sorry my ignorance, but perhaps someone here is able to answer this question straight from the line: is it possible for the surface made by delaunay triangulation to contain a hole in the middle of it?
If the answer is no - then there is a bug in ROOT, for I have such a case in my data. If answer is yes - sorry for wasting your time, I’ll have to code my own 2D interpolation procedure
I do, although not that short. One file in the archive is the script, second contains necessary data. One has to wait a while for the script to go over all “conincidencing points”. The whole is not well visible on TGraph2D plot - just a small white line. However histogram made from TGraph2D::Interpolate clearly shows it, inside the square (1.4, 400) (2.4, 440).
btw. the loop in the script makes graph for just one parameter. However, if one uncomments the line for making for all the parameters, it becomes visible, that only the last (39) par histogram does not contain the hole. deltri.zip (47 KB)
[quote=“couet”]Do yo also get 1000 of messages like:
Two of these three points are coincident 766 16 28
Unfortunately I did. However, I could not find any conincident points. Additionally, when I plot in carthesian coordinates, there are much less of such messages.
Despite them I get a plot, in which I do not see any hole.
Can you send me a picture showing what you call a " hole" ?[/quote]
It is hardly visible on TGraph2D, but well visible on TH2 with points that are results of interpolation of the TGraph2D. There is a possibility, that this is a bug of Interpolate() not the delaunay triagulation itself…
Yes … but that’s not that simple because the message occur after many transformation and the true points are not so easily available…Any way, as you saw it took me not too long to find out the faulty guy.
Yes, sorry I wasted your time. Sometimes long ago I assumed that TGraph2D can produce such messages when there are truly no coincident points. Connecting this with my attempt to find such points according to the printed message lead to this unnecessary problem report.