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Re: NaN problems [message #43703 is a reply to message #43584]

Sat, 23 April 2005 12:48

R.Bauer
Messages: 1424
Registered: November 1998

Senior Member

David Fanning wrote:

> Y.T. writes:
>
>> I don't have access to IDL on a win-box, but I have a (potentially
>> stupid) question: On that page of yours where you write
>>
>> IDL> print, array ne array
>> 0 0 0 0 0
>>
>> have you tried the converse, i.e.
>>
>> IDL> print, array eq array
>>
>> ?
>>
>> I am asking since, while it is true that a NaN is not equal to a NaN it
>> does not seem to follow (to my wrinkled brain) that a NaN is
>> necessarily UNequal to a NaN.
>>
>> In your version you test for the latter, and I'm kinda curious what
>> would happen if you tried the former...
>
> Well, looks like some things have changed since that
> article was written. Here is what I get in IDL 6.1 on Windows:
>
> IDL> a = [ 1.0, 2.0, !Values.F_NAN, 4.0, !Values.F_NAN ]
> IDL> print, a ne a
> 0 0 1 0 1
> % Program caused arithmetic error: Floating illegal operand
> IDL> print, a eq a
> 1 1 0 1 0
> % Program caused arithmetic error: Floating illegal operand
>
> Consistent, anyway. :-)
>
> Cheers,
>
> David

I got the same result without the warnings on the linux Version.
Probably we both should try it with the actual 6.1.1 version. For windows
it's a 2MB download and I don't know why it is for linux 60MB. ;-)

cheers

Reimar

--
Forschungszentrum Juelich
email: R.Bauer@fz-juelich.de
http://www.fz-juelich.de/icg/icg-i/
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[Message index]

		NaN problems By: David Lopez Pons on Thu, 21 April 2005 06:37
		Re: NaN problems By: R.Bauer on Sat, 23 April 2005 12:48
		Re: NaN problems By: David Fanning on Fri, 22 April 2005 20:38
		Re: NaN problems By: yp on Mon, 25 April 2005 16:51
		Re: NaN problems By: yp on Mon, 25 April 2005 16:49
		Re: NAN Problem By: R.Bauer on Thu, 14 January 2010 00:49
		Re: NAN Problem By: penteado on Wed, 13 January 2010 16:15
		Re: NAN Problem By: R.G.Stockwell on Wed, 13 January 2010 16:00
		Re: NAN Problem By: Foldy Lajos on Wed, 13 January 2010 13:00
		Re: NAN Problem By: penteado on Wed, 13 January 2010 12:59
		Re: NAN Problem By: David Fanning on Wed, 13 January 2010 12:39
		Re: NAN Problem By: jeanh on Wed, 13 January 2010 12:28

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