Tony S Yu wrote:
> I was using pcolor with very large numbers and a small vrange (vmax -
> vmin), and ran into a float to integer conversion problem. Large numbers
> get converted to *negative* integers by astype (see numpy thread
> <http://projects.scipy.org/pipermail/numpy-discussion/2008-October/038159.html>)
> in
> colors.Colormap.__call__.
>
> I'm not sure if this is even worth fixing since almost no one would run
> into this problem (unless you were doing something stupid, like trying
> to use pcolor as a 2D zero finder :). For the error to occur, you have
> to set vmin/vmax values (otherwise, the data is properly normalized
> before converting to integers), and your data has to greatly exceed
> these limits.
Tony,
Thank you.
I committed the change; it looks like the cost of the extra clip is
negligible, and it is nice to make the behavior correct even under
extreme conditions.
Eric
>
> Cheers,
> -Tony
>
>
> ------------------------------------------------------------------------
>
>
> Example of the problem:
> #~~~~~~~~~~~~~
> import matplotlib.pyplot as plt
> import numpy as np
>
> cmap = plt.cm.gray
> cmap.set_over('r', 1.0)
> cmap.set_under('g', 1.0)
> cmap.set_bad('b', 1.0)
>
> eps = 1E-8
>
> A = np.arange(100).reshape(10, 10)
> plt.pcolor(A, vmin=50, vmax=50+eps, cmap=cmap)
> # the plot should be about half red and half green (plus a black square)
> # without patch, some of the red squares are filled green
> plt.show()
> #~~~~~~~~~~~~~
>
>
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