Replace -inf with zero value
Use isneginf
http://docs.scipy.org/doc/numpy/reference/generated/numpy.isneginf.html#numpy.isneginf
x[numpy.isneginf(x)] = 0
Use isneginf
http://docs.scipy.org/doc/numpy/reference/generated/numpy.isneginf.html#numpy.isneginf
x[numpy.isneginf(x)] = 0