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Re: VALUE_LOCATE and NaNs [message #81815 is a reply to message #81813]

Thu, 25 October 2012 08:05

Jeremy Bailin
Messages: 618
Registered: April 2008

Senior Member

On 10/25/12 9:48 AM, Fab wrote:
> On 10/25/2012 03:41 PM, Kai Muehlbauer wrote:
>>
>> I can confirm:
>>
>> IDL> print, !VERSION
>> { x86_64 linux unix linux 7.1.1 Aug 21 2009 64 64}
>>
>> IDL> data = FINDGEN(10) & data[0] = !VALUES.F_NAN
>> IDL> p = VALUE_LOCATE(LINDGEN(10), data) & print, p[0]
>> -1
>> % Program caused arithmetic error: Floating illegal operand
>> IDL>
>>
>> Cheers,
>> Kai
>>
>
> At least the answer is right, but the warning is there ;-)
> So three different behaviours of value locate with three input types:
>
> IDL> data = FINDGEN(10) & data[0] = !VALUES.F_NAN
> IDL> p = VALUE_LOCATE(INDGEN(10), data) & print, p[0]
> 0
> % Program caused arithmetic error: Floating illegal operand
> IDL> p = VALUE_LOCATE(LINDGEN(10), data) & print, p[0]
> -1
> % Program caused arithmetic error: Floating illegal operand
> IDL> p = VALUE_LOCATE(FINDGEN(10), data) & print, p[0]
> -1
>
>

I agree with Craig - there is no well-defined answer for what
VALUE_LOCATE should return when faced with a NaN. But it also shouldn't
give different answers depending on the type of location array.

-Jeremy.

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[Message index]

		Re: VALUE_LOCATE and NaNs By: Fabzi on Thu, 25 October 2012 08:07
		Re: VALUE_LOCATE and NaNs By: Jeremy Bailin on Thu, 25 October 2012 08:05
		Re: VALUE_LOCATE and NaNs By: wlandsman on Thu, 25 October 2012 08:01
		Re: VALUE_LOCATE and NaNs By: lecacheux.alain on Thu, 25 October 2012 07:59
		Re: VALUE_LOCATE and NaNs By: Craig Markwardt on Thu, 25 October 2012 07:30
		Re: VALUE_LOCATE and NaNs By: Fabzi on Thu, 25 October 2012 06:48
		Re: VALUE_LOCATE and NaNs By: Kai Muehlbauer on Thu, 25 October 2012 06:41
		Re: VALUE_LOCATE and NaNs By: lecacheux.alain on Thu, 25 October 2012 04:10
		Re: VALUE_LOCATE and NaNs By: Fabzi on Thu, 25 October 2012 02:57
		Re: VALUE_LOCATE and NaNs By: lecacheux.alain on Thu, 25 October 2012 02:34

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