cf.DomainAncillary.log

DomainAncillary.log(base=10, bounds=True, i=False)[source]

The logarithm of the data array.

By default the natural logarithm is taken, but any base may be specified.

See also

exp

Examples 1: 
>>> g = f.log()
Parameters:
base: number, optional

The base of the logiarthm. By default a natural logiarithm is taken.

i: bool, optional

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

The domain ancillary with the logarithm of data array values.
Examples 2: 
>>> f.data
<CF Data: [[1, 2]]>
>>> f.log().data
<CF Data: [[0.0, 0.69314718056]] ln(re 1)>

>>> f.data
<CF Data: [[1, 2]] 2>
>>> f.log().data
<CF Data: [[0.0, 0.69314718056]] ln(re 2 1)>

>>> f.data
<CF Data: [[1, 2]] kg s-1 m-2>
>>> f.log().data
<CF Data: [[0.0, 0.69314718056]] ln(re 1 m-2.kg.s-1)>

>>> g = f.log(i=True)
>>> g is f
True

>>> f.Units
<CF Units: >
>>> f.log()
ValueError: Can't take the logarithm to the base 2.718281828459045 of <CF Units: >