Python 3.6.8 (default, Aug 20 2019, 17:12:48)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from mpmath import *
>>> import numpy as np
>>> mp.hyp1f1(2.5,2.2,np.nan)
mpf('1.0')
>>> mp.hyp1f1(1,2.2,np.nan)
mpf('1.0')
>>> mp.hyp1f1(1,2002.2,np.nan)
mpf('1.0')
mpmath version: 1.1.0
When the third argument for hyp1f1 in the mp context is a NaN, a 1 is returned
regardless of the other input. For what it's worth, the fp context
version throws a NoConvergence Exception. For the same input, SciPy
and GSL agree on an output of NaN.
Example: