cf.Field.log

Field.log(base=10, i=False)

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 field in place. By default a new field is created. In either case, a field is returned.

Returns:

out : cf.Field

The field with the logarithm of data array values.

Examples: 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: >