[Matplotlib-users] Bug in Triangulation causes infinite loop if 4 or more duplicate points are used in tricontour()
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] 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 signature.asc Description: OpenPGP digital signature -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Bug in Triangulation causes infinite loop if 4 or more duplicate points are used in tricontour()
Hi Kacper, Just to be clear, is it tri.Triangulation(x, y) that hangs, or is it plt.tricontour(…)? -- 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 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] 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 -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net (mailto:Matplotlib-users@lists.sourceforge.net) https://lists.sourceforge.net/lists/listinfo/matplotlib-users -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Bug in Triangulation causes infinite loop if 4 or more duplicate points are used in tricontour()
On 16 Apr 2012 22:31, Damon McDougall 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 -- Damon McDougall 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 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] 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 -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Bug in Triangulation causes infinite loop if 4 or more duplicate points are used in tricontour()
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 -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
