Inverse hyperbolic cosine, element-wise.
LAX-backend implementation of
arccosh(). Original docstring below.
arccosh(x, /, out=None, *, where=True, casting=’same_kind’, order=’K’, dtype=None, subok=True[, signature, extobj])
x (array_like) – Input array.
arccosh – Array of the same shape as x. This is a scalar if x is a scalar.
- Return type
arccosh is a multivalued function: for each x there are infinitely many numbers z such that cosh(z) = x. The convention is to return the z whose imaginary part lies in [-pi, pi] and the real part in
For real-valued input data types, arccosh 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, arccosh is a complex analytical function that has a branch cut [-inf, 1] and is continuous from above on it.
M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions”, 10th printing, 1964, pp. 86. http://www.math.sfu.ca/~cbm/aands/
Wikipedia, “Inverse hyperbolic function”, https://en.wikipedia.org/wiki/Arccosh
>>> np.arccosh([np.e, 10.0]) array([ 1.65745445, 2.99322285]) >>> np.arccosh(1) 0.0