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Re: Arithmetic error [message #29107 is a reply to message #12177]

Thu, 31 January 2002 02:11

Nigel Wade
Messages: 286
Registered: March 1998

Senior Member

Ed Wright wrote:

>
> To: IDL
> From: Ed Wright, JPL
>
> I require assistance with an odd problem. My current projects involves
> creating a dlm module of some 200+ routines from a library of 1500+
> routines. Several of the IDL callable routines replicate intrinsic IDL
> calls. While testing one such routine that calculates determinate of a 3X3
> I encountered a problem. The numerical result between my determinant
> function and determn matches to 10^(-16).
>
> Now the odd thing. Under certain circumstances the use of my determinant
> function as an argument in another routine call causes an error:
>
> % Program caused arithmetic error: Floating illegal operand.
>

That error means somewhere in your code you have generated a NaN (Not a
Number). The operations which generate NaNs include 0/0, Inf*0, sqrt(<0)
Inf-Inf,Inf/Inf (there may be others...).

Since you don't have a preceding 'Floating divide by zero', it's a fair bet
your error doesn't involve Inf. So, all you have to do is look through your
code to find where you might have a 0/0 or sqrt(<0). ;-)

--
-----------------------------------------------------------
Nigel Wade, System Administrator, Space Plasma Physics Group,
University of Leicester, Leicester, LE1 7RH, UK
E-mail : nmw@ion.le.ac.uk
Phone : +44 (0)116 2523568, Fax : +44 (0)116 2523555

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[Message index]

		Arithmetic error from NR_MACHAR() By: Heiko H�nnefeld on Mon, 29 June 1998 00:00
		Re: Arithmetic error By: Nigel Wade on Fri, 01 February 2002 02:12
		Re: Arithmetic error By: Paul van Delst on Thu, 31 January 2002 10:41
		Re: Arithmetic error By: Ed Wright on Thu, 31 January 2002 07:53
		Re: Arithmetic error By: Nigel Wade on Thu, 31 January 2002 02:11

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