Turn off ZeroDivisionError?

Steve Holden steve at holdenweb.com
Fri Feb 15 20:35:34 CET 2008


Mark Dickinson wrote:
> On Feb 14, 11:09 pm, John Nagle <na... at animats.com> wrote:
>>      You also need to think about how conditionals interact with
>> quiet NANs.  Properly, comparisons like ">" have three possibilities:
> 
> True.  There was a recent change to Decimal to make comparisons (other
> than !=, ==) with NaNs do the "right thing":  that is, raise a Python
> exception, unless the Invalid flag is not trapped, in which case they
> return False (and also raise the Invalid flag).  I imagine something
> similar would make sense for floats.
> 
>> True, False, and "raise".  Many implementations don't do that well,
>> which means that you lose trichotomy.  "==" has issues; properly,
>> "+INF" is not equal to itself.
> 
> I don't understand:  why would +INF not be equal to itself?  Having
> INF == INF be True seems like something that makes sense both
> mathematically and computationally.
>  [...]

There are an uncountable number of infinities, all different.

regards
  Steve
-- 
Steve Holden        +1 571 484 6266   +1 800 494 3119
Holden Web LLC              http://www.holdenweb.com/




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