How do you do natural logs (e.g. “ln()”) with numpy in Python?

问题

Using numpy, how can I do the following:

ln(x)

Is it equivalent to:

np.log(x)

I apologise for such a seemingly trivial question, but my understanding of the difference between log and ln is that ln is logspace e?

回答1:

np.log is ln, whereas np.log10 is your standard base 10 log.

Relevant documentation:

http://docs.scipy.org/doc/numpy/reference/generated/numpy.log.html

http://docs.scipy.org/doc/numpy/reference/generated/numpy.log10.html

回答2:

Correct, np.log(x) is the Natural Log (base e log) of x.

For other bases, remember this law of logs: log-b(x) = log-k(x) / log-k(b) where log-b is the log in some arbitrary base b, and log-k is the log in base k, e.g.

here k = e

l = np.log(x) / np.log(100)

and l is the log-base-100 of x

回答3:

I usually do like this:

from numpy import log as ln

Perhaps this can make you more comfortable.

回答4:

from numpy.lib.scimath import logn
from math import e

#using: x - var
logn(e, x)

来源：https://stackoverflow.com/questions/10593100/how-do-you-do-natural-logs-e-g-ln-with-numpy-in-python