Replace -inf with zero value

There is:

from numpy import inf
x[x == -inf] = 0

Use isneginf http://docs.scipy.org/doc/numpy/reference/generated/numpy.isneginf.html#numpy.isneginf

x[numpy.isneginf(x)] = 0

Perhaps even easier and more flexible to use numpy.nan_to_num:

numpy.nan_to_num(x, neginf=0) 

Out[1]: array([ 0.        ,  0.        , 37.49668579])