/Users/cmalone/code/yt-x86_64/lib/python2.7/site-packages/matplotlib-1.4.0-py2.7-macosx-10.4-x86_64.egg/matplotlib/axis.py:1016: UserWarning: Unable to find pixel distance along axis for interval padding; assuming no interval padding needed.
warnings.warn("Unable to find pixel distance along axis for interval padding; assuming no interval padding needed.")
/Users/cmalone/code/yt-x86_64/lib/python2.7/site-packages/matplotlib-1.4.0-py2.7-macosx-10.4-x86_64.egg/matplotlib/axis.py:1023: UserWarning: Unable to find pixel distance along axis for interval padding; assuming no interval padding needed.
warnings.warn("Unable to find pixel distance along axis for interval padding; assuming no interval padding needed.")