1.#QNAN Solution

[Greg Corradini]

Thanks for you help Grant

Grant Edwards wrote:
> 
> On 2007-05-08, Greg Corradini <gregcorradini at gmail.com> wrote:
> 
>> I'm running descriptive stats on mileages from a database
>> (float numbers, about a million records). My sum returns
>> 1.#QNAN, which I understand from searching this forum is an
>> error.
> 
> Not necessarily.  You've ended up with a floating point "not a
> number" value (AKA a NaN).  That might or might not be an
> error.  Whether it's an error not not depends on your input
> data and your algorithm.
> 
>> While I'm looking for help in solving this problem, I'm more
>> interested in a general explanation about the cause of this
>> problem.
> 
> If you're asking how you end up with a NaN, there are several
> ways to generate a NaN:
> 
>   0/0
>   
>   Inf*0
>   
>   Inf/Inf
>   
>   Inf-Inf
>   
>   Almost any operation on a NaN 
> 
> http://en.wikipedia.org/wiki/NaN
> http://steve.hollasch.net/cgindex/coding/ieeefloat.html
> 
> -- 
> Grant Edwards                   grante             Yow! Spreading peanut
>                                   at               butter reminds me of
>                                visi.com            opera!!  I wonder why?
> -- 
> http://mail.python.org/mailman/listinfo/python-list
> 
> 

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