[SciPy-user] exponential integral behaviour near -20

David Joyner wdj@usna....
Mon Dec 15 22:39:39 CST 2008


A user reported a bug on the sage-support list (Sage, www.sagemath.org, includes scipy) for the exponential 
integral. This seems to illustrate the idea:

>>> import scipy.special, math
>>> -scipy.special.exp1(-complex(19.9999990))
>>> -scipy.special.exp1(-complex(19.9999991))

Any ideas on what would cause this?

- David Joyner

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