Natural logarithm, element-wise.
LAX-backend implementation of
log(). Original docstring below.
log(x, /, out=None, *, where=True, casting=’same_kind’, order=’K’, dtype=None, subok=True[, signature, extobj])
The natural logarithm log is the inverse of the exponential function, so that log(exp(x)) = x. The natural logarithm is logarithm in base e.
x (array_like) – Input value.
y – The natural logarithm of x, element-wise. This is a scalar if x is a scalar.
- Return type
Logarithm is a multivalued function: for each x there is an infinite number of z such that exp(z) = x. The convention is to return the z whose imaginary part lies in [-pi, pi].
For real-valued input data types, log always returns real output. For each value that cannot be expressed as a real number or infinity, it yields
nanand sets the invalid floating point error flag.
For complex-valued input, log is a complex analytical function that has a branch cut [-inf, 0] and is continuous from above on it. log handles the floating-point negative zero as an infinitesimal negative number, conforming to the C99 standard.
M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions”, 10th printing, 1964, pp. 67. http://www.math.sfu.ca/~cbm/aands/
Wikipedia, “Logarithm”. https://en.wikipedia.org/wiki/Logarithm
>>> np.log([1, np.e, np.e**2, 0]) array([ 0., 1., 2., -Inf])