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Re: IDL 6.1 EPS error [message #41450]

Fri, 29 October 2004 07:43

Karl Schultz
Messages: 341
Registered: October 1999

Senior Member

"Michael Wallace" <mwallace.no.spam@no.spam.swri.edu.invalid> wrote in
message news:10o2odm89ncav58@corp.supernews.com...
>> I will try out this solution. It'll take me a few minutes to find all
>> the places in my code where I use empty strings.
>
> Well, I tried replacing my empty strings with ' ' strings and there are
> no longer nan values in the EPS. Everything appears to work okay. I
> did happen to notice that the underflow error is still present in
> IDLgrClipboard -> draw, but it doesn't seem to cause any problems.
>
> % Program caused arithmetic error: Floating underflow

Yes, I've seen this. As you probably know, it is not a serious problem,
because the underflow just indicates a loss of precision, and the true value
is closely approximated by zero.

I tried once to track this down and ended up thinking that the actual
underflow is occuring in Mesa, which is the OpenGL-like library we use to
produce the vector output. There are gobs of floating point math going on
inside of Mesa, and IDL is just reporting the underflow state after a fairly
long sequence of calls into Mesa. I'll have another look for next release.

Karl

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[Message index]

		Re: IDL 6.1 EPS error By: Karl Schultz on Fri, 29 October 2004 07:43
		Re: IDL 6.1 EPS error By: Michael Wallace on Thu, 28 October 2004 14:16
		Re: IDL 6.1 EPS error By: Randall Skelton on Thu, 28 October 2004 13:34
		Re: IDL 6.1 EPS error By: Karl Schultz on Thu, 28 October 2004 08:22
		Re: IDL 6.1 EPS error By: Mark Hadfield on Wed, 27 October 2004 16:10
		Re: IDL 6.1 EPS error By: Karl Schultz on Wed, 27 October 2004 15:57
		Re: IDL 6.1 EPS error By: Michael Wallace on Wed, 27 October 2004 15:37
		Re: IDL 6.1 EPS error By: Karl Schultz on Wed, 27 October 2004 15:32
		Re: IDL 6.1 EPS error By: Michael Wallace on Wed, 27 October 2004 15:29
		Re: IDL 6.1 EPS error By: Mark Hadfield on Wed, 27 October 2004 13:50
		Re: IDL 6.1 EPS error By: Michael Wallace on Wed, 27 October 2004 10:26

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