Return input with invalid data masked and replaced by a fill value.
Invalid data means values of nan, inf, etc.
| Parameters : | a : array_like 
 copy : bool, optional 
 fill_value : scalar, optional 
  | 
|---|---|
| Returns : | b : MaskedArray 
  | 
Notes
A copy is performed by default.
Examples
>>> x = np.ma.array([1., -1, np.nan, np.inf], mask=[1] + [0]*3)
>>> x
masked_array(data = [-- -1.0 nan inf],
             mask = [ True False False False],
       fill_value = 1e+20)
>>> np.ma.fix_invalid(x)
masked_array(data = [-- -1.0 -- --],
             mask = [ True False  True  True],
       fill_value = 1e+20)
>>> fixed = np.ma.fix_invalid(x)
>>> fixed.data
array([  1.00000000e+00,  -1.00000000e+00,   1.00000000e+20,
         1.00000000e+20])
>>> x.data
array([  1.,  -1.,  NaN,  Inf])