[Matplotlib-users] log-log errorbar plots with errorbars including zero

[Dan C. <jd...@uw...>]

I regularly make log-log errorbar plots where the errors are larger than
the y values.  This means that the error bar goes a finite distance
upwards, but should go infinitely far downwards.  In Debian's 0.87.7-0.3
package, just the top portion is drawn, which seems like a reasonable
solution.  But in Ubuntu's 0.90.1-2ubuntu1 package, trying to do a
plot like this causes an error.  Any ideas?

Dan

$ python
Python 2.5.1 (r251:54863, Oct  5 2007, 13:36:32) 
[GCC 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from pylab import *
>>> errorbar([1],[1],[2])
(<matplotlib.lines.Line2D instance at 0xb5ac024c>, [<matplotlib.lines.Line2D instance at 0xb5ac00cc>, <matplotlib.lines.Line2D instance at 0xb5ac00ec>], [<matplotlib.collections.LineCollection instance at 0xb5abdfac>])
>>> gca().set_yscale('log')
>>> show()
Exception in Tkinter callback
Traceback (most recent call last):
  File "lib-tk/Tkinter.py", line 1406, in __call__
    return self.func(*args)
  File "/usr/lib/python2.5/site-packages/matplotlib/backends/backend_tkagg.py", line 151, in resize
    self.show()
  File "/usr/lib/python2.5/site-packages/matplotlib/backends/backend_tkagg.py", line 154, in draw
    FigureCanvasAgg.draw(self)
  File "/usr/lib/python2.5/site-packages/matplotlib/backends/backend_agg.py", line 392, in draw
    self.figure.draw(renderer)
  File "/usr/lib/python2.5/site-packages/matplotlib/figure.py", line 601, in draw
    for a in self.axes: a.draw(renderer)
  File "/usr/lib/python2.5/site-packages/matplotlib/axes.py", line 1286, in draw
    a.draw(renderer)
  File "/usr/lib/python2.5/site-packages/matplotlib/collections.py", line 700, in draw
    transoffset)
ValueError: Domain error on transOffset->operator in draw_line_collection