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Re: Arithmetic error [message #29104 is a reply to message #12177]

Thu, 31 January 2002 07:53

Ed Wright
Messages: 39
Registered: February 1999

Member

in article a3b58p$kb2i$1@rook.le.ac.uk, Nigel Wade at nmw@ion.le.ac.uk wrote
on 1/31/02 2:11 AM:

> 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...).

By code, should I take it to mean the external C code?

>
> 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). ;-)

Oh, is that all. No problem. 300k lines - let me at them.... Mr. Codebuster,
that's me.

As always,
Ed Wright

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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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