NaN again - and IEEE arithmatics

[Huaiyu Zhu]

Sometime ago I asked about reading back from a file containing arrays with
NaN as elements.  Someone kindly suggested

>>> from math import exp
>>> NaN = exp(1000)/exp(1000)
>>> NaN
nan

However this breaks in 1.6 (or maybe because it is installed on another
machine).

>>> import math
>>> NaN = math.exp(1000) / math.exp(1000)
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  OverflowError: math range error

Any suggestion of how to deal with it in this case?  Is there a generic way?

If I understand correctly, NaN is a standard feature in IEEE floating point
arithmatics.  So why isn't there a predefined class or object for NaN?  It
might go into the math or Numeric module, I think.

Thanks 

-- 
Huaiyu Zhu                               hzhu at knowledgetrack.com