Some functions don't handle inifinities and nans about mpmath-2 HOT 3 CLOSED

>>> for f in [lambda x: nthroot(x, 3), sqrt, cos, log, atan, cosh]:
...   print f(mpf('inf'))
...   print f(mpf('nan'))
...
+inf
nan
+inf
nan
nan
nan
+inf
nan
1.5707963267949
nan
+inf
nan
>>> mpf('nan')**2
mpf('nan')
>>> mpf('inf')**2
mpf('+inf')

Are there still some functions left?

Yes, plenty.

>>> acosh(nan)
mpc(real='0.0', imag='nan')

>>> hyp2f1(nan,nan,nan,nan)
(infinite recursion)

There are still some functions that will crash or return strange things at 
infs/nans, but the situation is much better, and there are lots of tests.