On Monday, 16 April 2012 at 16:34, Kacper Kowalik wrote: > > On 16 Apr 2012 22:31, "Damon McDougall" <d.mcdoug...@warwick.ac.uk > (mailto:d.mcdoug...@warwick.ac.uk)> wrote: > > > > Hi Kacper, > > > > Just to be clear, is it tri.Triangulation(x, y) that hangs, or is it > > plt.tricontour(…)? > It's plt.tricontour that hangs, tri.Triangulation properly issues warning > about duplicates. > Cheers, > Kacper > > On Monday, 16 April 2012 at 14:28, Kacper Kowalik wrote: > >> > >> Hi, > >> I haven't been able to pin point it exactly but following script: > >> > >> import matplotlib.pyplot as plt > >> import matplotlib.tri as tri > >> import numpy as np > >> from numpy.random import uniform, seed > >> > >> seed(0) > >> npts = 200 > >> x = uniform(-2,2,npts) > >> y = uniform(-2,2,npts) > >> z = x*np.exp(-x**2-y**2) > >> > >> y[1:3] = x[0] # 4 or more duplicate points make tricontour hang!!! > >> x[1:3] = y[0] You should call z = x*np.exp(-x**2-y**2) _before_ changing the points you're triangulating. Having said that, I see the same behaviour even if I change the vertices before I compute z. > >> triang = tri.Triangulation(x, y) > >> plt.tricontour(x, y, z, 15, linewidths=0.5, colors='k') > >> > >> plt.show() > >> > >> > >> causes infinite loop in _tri.so. It happens in matplotlib-1.1.0 as well > >> as git HEAD. > >> I understand that my input is not exactly valid, but I'd rather see MPL > >> die than occupy my box for eternity ;) > >> Best regards, > >> Kacper I think the reason it's hanging is because you're trying to plot the contours of a function that is defined on an invalid triangulation (edges cross at points that are not in the vertex set). I think the best way to deal with this is to write a helper function to check the triangulation is valid. If it isn't, either tri.Triangulation(x, y) should fail, or the plotter should fail.
Anybody else have any suggestions? -- Damon McDougall d.mcdoug...@warwick.ac.uk (mailto:d.mcdoug...@warwick.ac.uk) http://damon.is-a-geek.com B2.39 Mathematics Institute University of Warwick Coventry West Midlands CV4 7AL United Kingdom
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