arccosh

arccosh(x, out=None, **kwargs)

Inverse hyperbolic cosine, element-wise.

Parameters:
x : ndarray or scalar

Input array.

out : ndarray or None, optional

A location into which the result is stored.
Returns:
arccosh : ndarray

Array of the same shape as x. This is a scalar if x is a scalar.

Notes

arccosh is a multivalued function: for each x there are infinitely many numbers z such that cosh(z) = x.

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 nan and sets the invalid floating point error flag.

This function differs from the original numpy.arccosh in the following aspects:
  • Do not support where, a parameter in numpy which indicates where to calculate.
  • Do not support complex-valued input.
  • Cannot cast type automatically. Dtype of out must be same as the expected one.
  • Cannot broadcast automatically. Shape of out must be same as the expected one.
  • If x is plain python numeric, the result won’t be stored in out.

Examples

>>> a = np.array([3.2, 5.0])
>>> np.arccosh(a)
array([1.8309381, 2.2924316])

>>> np.arccosh(1)
0.0