from brian2 import arctanh)
Inverse hyperbolic tangent element-wise.
x : array_like
out : ndarray
Array of the same shape as
arctanh()is a multivalued function: for each
xthere are infinitely many numbers
tanh(z) = x. The convention is to return the
zwhose imaginary part lies in
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
nanand sets the
invalidfloating point error flag.
For complex-valued input,
arctanh()is a complex analytical function that has branch cuts
[1, inf]and is continuous from above on the former and from below on the latter.
The inverse hyperbolic tangent is also known as
[R17] M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions”, 10th printing, 1964, pp. 86. http://www.math.sfu.ca/~cbm/aands/ [R18] Wikipedia, “Inverse hyperbolic function”, http://en.wikipedia.org/wiki/Arctanh
>>> np.arctanh([0, -0.5]) array([ 0. , -0.54930614])