numpy.emath.log2#
- emath.log2(x)[source]#
Compute the logarithm base 2 of x.
Return the “principal value” (for a description of this, see
numpy.log2
) of \(log_2(x)\). For real x > 0, this is a real number (log2(0)
returns-inf
andlog2(np.inf)
returnsinf
). Otherwise, the complex principle value is returned.- Parameters:
- xarray_like
The value(s) whose log base 2 is (are) required.
- Returns:
- outndarray or scalar
The log base 2 of the x value(s). If x was a scalar, so is out, otherwise an array is returned.
See also
Notes
For a log2() that returns
NAN
when real x < 0, usenumpy.log2
(note, however, that otherwisenumpy.log2
and thislog2
are identical, i.e., both return-inf
for x = 0,inf
for x = inf, and, notably, the complex principle value ifx.imag != 0
).Examples
We set the printing precision so the example can be auto-tested:
>>> np.set_printoptions(precision=4)
>>> np.emath.log2(8) 3.0 >>> np.emath.log2([-4, -8, 8]) array([2.+4.5324j, 3.+4.5324j, 3.+0.j ])