numpy.arctanh(x[, out]) =
Inverse hyperbolic tangent element-wise.
Parameters: |
x : array_like Input array. |
---|---|
Returns: |
out : ndarray Array of the same shape as |
See also
emath.arctanh
arctanh
is a multivalued function: for each x
there are infinitely many numbers z
such that tanh(z) = x
. The convention is to return the z
whose imaginary part lies in [-pi/2, pi/2]
.
For real-valued input data types, arctanh
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 complex-valued input, arctanh
is a complex analytical function that has branch cuts [-1, -inf]
and [1, inf]
and is continuous from above on the former and from below on the latter.
The inverse hyperbolic tangent is also known as atanh
or tanh^-1
.
[R7] | M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions”, 10th printing, 1964, pp. 86. http://www.math.sfu.ca/~cbm/aands/ |
[R8] | Wikipedia, “Inverse hyperbolic function”, http://en.wikipedia.org/wiki/Arctanh |
>>> np.arctanh([0, -0.5]) array([ 0. , -0.54930614])
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https://docs.scipy.org/doc/numpy-1.12.0/reference/generated/numpy.arctanh.html