numpy.log2(x, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj]) = <ufunc 'log2'>
Base2 logarithm of x
.
Parameters: 


Returns: 

New in version 1.3.0.
Logarithm is a multivalued function: for each x
there is an infinite number of z
such that 2**z = x
. The convention is to return the z
whose imaginary part lies in [pi, pi]
.
For realvalued input data types, log2
always returns real output. For each value that cannot be expressed as a real number or infinity, it yields nan
and sets the invalid
floating point error flag.
For complexvalued input, log2
is a complex analytical function that has a branch cut [inf, 0]
and is continuous from above on it. log2
handles the floatingpoint negative zero as an infinitesimal negative number, conforming to the C99 standard.
>>> x = np.array([0, 1, 2, 2**4]) >>> np.log2(x) array([Inf, 0., 1., 4.])
>>> xi = np.array([0+1.j, 1, 2+0.j, 4.j]) >>> np.log2(xi) array([ 0.+2.26618007j, 0.+0.j , 1.+0.j , 2.+2.26618007j])
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Licensed under the 3clause BSD License.
https://docs.scipy.org/doc/numpy1.17.0/reference/generated/numpy.log2.html