cf.FieldAncillary.mask_invalid

FieldAncillary.mask_invalid(i=False)[source]

Mask the array where invalid values occur.

Note that:

  • Invalid values are Nan or inf
  • Invalid values in the results of arithmetic operations only occur if the raising of FloatingPointError exceptions has been suppressed by cf.Data.seterr.
  • If the raising of FloatingPointError exceptions has been allowed then invalid values in the results of arithmetic operations it is possible for them to be automatically converted to masked values, depending on the setting of cf.Data.mask_fpe. In this case, such automatic conversion might be faster than calling mask_invalid.

See also

cf.Data.mask_fpe, cf.Data.seterr

Examples 1: 
>>> g = f.mask_invalid()
Parameters:
i: bool, optional

If True then update the field ancillary in place. By default a new field ancillary is created. In either case, a field ancillary is returned.
Returns:

out: cf.FieldAncillary
Examples 2: 
>>> print f.array
[ 0.  1.]
>>> print g.array
[ 1.  2.]

>>> old = cf.Data.seterr('ignore')
>>> h = g/f
>>> print h.array
[ inf   2.]
>>> h.mask_invalid(i=True)
>>> print  h.array
[--  2.]

>>> h = g**12345
>>> print h.array
[ 1.  inf]
>>> h = h.mask_invalid()
>>> print h.array
[1.  --]

>>> old = cf.Data.seterr('raise')
>>> old = cf.Data.mask_fpe(True)
>>> print (g/f).array
[ --  2]
>>> print (g**12345).array
[1.  -- ]