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Re: Incorrect behavior of /NAN [message #30021]

Thu, 04 April 2002 11:38

Paul van Delst
Messages: 364
Registered: March 1997

Senior Member

Jaco van Gorkom wrote:
>
> "Paul van Delst" <paul.vandelst@noaa.gov> wrote in message
> news:3CAC9914.B52D1669@noaa.gov...
>> Kenneth Bowman wrote:
>>> ....
>>> IDL> print, mean([a, a], /nan)
>>> NaN
>>
>> I think the last result *here* is wrong :o) Shouldn't it be 1.0? What is
> MEAN in this case
>> but:
>>
>> total([a,a],/NAN) / n_elements(non-nan values only)
>>
>> Both the numerator and denominator are 0.
>
> So you mean that 0 / 0 = 1.0 ? Or 0. / 0. = 1.0 ?
> In any case, IDL seems to disagree with you here: :-)
>
> IDL> print, 0./0.
> -NaN
> % Program caused arithmetic error: Floating illegal operand
>
> IDL> print, 0/0
> 0
> % Program caused arithmetic error: Integer divide by 0
>

Maybe a holistic division operator is required in these sorts of cases. :o)

paulv

--
Paul van Delst Religious and cultural
CIMSS @ NOAA/NCEP purity is a fundamentalist
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[Message index]

		Re: Incorrect behavior of /NAN By: Paul van Delst on Thu, 04 April 2002 11:38
		Re: Incorrect behavior of /NAN By: Jaco van Gorkom on Thu, 04 April 2002 10:38
		Re: Incorrect behavior of /NAN By: Paul van Delst on Thu, 04 April 2002 10:19
		Re: Incorrect behavior of /NAN By: Craig Markwardt on Thu, 04 April 2002 09:32
		Re: Incorrect behavior of /NAN By: K. Bowman on Fri, 05 April 2002 10:20
		Re: Incorrect behavior of /NAN By: Mark Hadfield on Thu, 04 April 2002 13:06
		Re: Incorrect behavior of /NAN By: Craig Markwardt on Thu, 04 April 2002 18:26

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