numpy.arctanh(x) for x >= 1 returns NaN but I want complex
Add +0j to your real inputs to make them complex numbers.
Numpy is following a variation of the maxim "Garbage in, Garbage out."
Float in, float out.
>>> import numpy as np>>> np.sqrt(-1)__main__:1: RuntimeWarning: invalid value encountered in sqrtnanComplex in, complex out.
>>> numpy.sqrt(-1+0j)1j>>> numpy.arctanh(24+0j)(0.0416908044695255-1.5707963267948966j)