-
numpy.arctanh(x[, out]) =
-
Inverse hyperbolic tangent element-wise.
Parameters: x : array_like
Input array.
Returns: out : ndarray
Array of the same shape as
x
.See also
emath.arctanh
Notes
arctanh
is a multivalued function: for eachx
there are infinitely many numbersz
such thattanh(z) = x
. The convention is to return thez
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 yieldsnan
and sets theinvalid
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
ortanh^-1
.References
[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 Examples
>>> np.arctanh([0, -0.5]) array([ 0. , -0.54930614])
numpy.arctanh()
2017-01-10 18:12:43
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