Ray Speth wrote: > I believe I have found a simple change that improves the rendering speed > of quiver plots, which can be quite slow for large vector fields. Based > on some profiling, the problem appears to stem from the use of numpy's > MaskedArrays in PolyCollection.set_verts. If I add the following line to > the top of the PolyCollection.set_verts function in collections.py: > > verts = np.asarray(verts) > > I find that quiver plots are drawn about 3 times as quickly, going from > 2.6 seconds for a 125x125 field to 0.65 seconds. This does not seem to > break the use of MaskedArrays as inputs, and masked regions are still > hidden in the final plot. I do not know if this has any adverse effects > in other classes that inherit from PolyCollection.
I made a change in PolyCollection.set_verts that has the effect of your suggestion but without affecting masked argument inputs in general. I also made a bunch of other changes in quiver.py to speed things up with or without masked inputs, but their net effect is minimal in practice; your suggestion was the key. I get a factor of 2, not 3; I think this must be a difference in our machines, though. In any case, I'm glad you found the time sink. Eric > > Using: > python 2.6.2 on Windows XP > numpy 1.3.0 > matplotlib 0.98.5.3, Qt4Agg backend > > I do not know why iterating over MaskedArrays is so slow, but perhaps > this information can be used to speed up some other functions as well. > > Ray Speth > > ------------------------------------------------------------------------------ > _______________________________________________ > Matplotlib-devel mailing list > Matplotlib-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-devel ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
