gistfile1.txt

Traceback (most recent call last):
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/backends/backend_macosx.py", line 136, in _draw
    self.figure.draw(renderer)
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/artist.py", line 68, in draw_wrapper
    return draw(artist, renderer, *args, **kwargs)
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/figure.py", line 1262, in draw
    renderer, self, dsu, self.suppressComposite)
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/image.py", line 139, in _draw_list_compositing_images
    a.draw(renderer)
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/artist.py", line 68, in draw_wrapper
    return draw(artist, renderer, *args, **kwargs)
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/axes/_base.py", line 2374, in draw
    mimage._draw_list_compositing_images(renderer, self, dsu)
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/image.py", line 139, in _draw_list_compositing_images
    a.draw(renderer)
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/artist.py", line 68, in draw_wrapper
    return draw(artist, renderer, *args, **kwargs)
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/image.py", line 470, in draw
    renderer, renderer.get_image_magnification())
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/image.py", line 694, in make_image
    unsampled=unsampled)
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/image.py", line 360, in _make_image
    A = self.norm(A)
  File "/Users/goldbaum/Documents/matplotlib/lib/matplotlib/colors.py", line 929, in __call__
    resdat -= vmin
  File "/Users/goldbaum/Documents/yt-hg/yt/units/yt_array.py", line 939, in __isub__
    oth = sanitize_units_add(self, other, "subtraction")
  File "/Users/goldbaum/Documents/yt-hg/yt/units/yt_array.py", line 163, in sanitize_units_add
    raise YTUnitOperationError(op_string, inp.units, dimensionless)
yt.utilities.exceptions.YTUnitOperationError: The subtraction operator for YTArrays with units (km) and (1) is not well defined.