[matplotlib-devel] strange message in contour

[<kei...@bt...>]

Using pyplot.contour, I'm getting

/usr/lib/pymodules/python2.7/matplotlib/contour.py:374: RuntimeWarning: invalid value encountered in true_divide
  dist = np.add.reduce(([(abs(s)[i]/L[i]) for i in range(xsize)]),-1)

although the resulting plot seems to be ok.

Keith