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Re: IDL Memory Leaks [message #27671]

Mon, 05 November 2001 13:58

Myron Brown
Messages: 10
Registered: December 1999

Junior Member

David,

Thanks. I am using the TEMPORARY function. I know memory is leaking because the
Windows task manager indicates that my IDL process is consuming more and more
memory as time goes on. Of course, IDL doesn't realize this (i.e. HELP, /MEMORY
indicates no increase in memory usage).

Two questions:

1. How does UNDEFINE differ from setting the variable to zero (a and b below)?
The result appears to be the same, but is it?

(a) IF (N_Elements(varname) NE 0) THEN tempvar = Size(Temporary(varname))
(b) varname = 0

2. When my routine returns, does the memory allocated in that routine not get
free'd since the variables are no longer in scope? Are there cases when this is
not true?

Myron

David Fanning wrote:

> Myron Brown (brownmz1@jhuapl.edu) writes:
>
>> 4. The code includes repetitive reassignments of variables to large arrays,
>> even within a routine (still in scope). I tried to assign variables to zero
>> each time, but it doesn't seem to make a difference. Should this really be
>> necessary?
>
> I'd like to see how you are doing this (I hope you
> are using the TEMPORARY function!), as this is more
> than likely the source of your problem. You don't say
> how you know you are "leaking memory", but this is the
> kind of thing that will eat up process memory if you
> are not careful.
>
> If you have the same variable on both sides of an equal
> sign, you really need something like this:
>
> image = Temporary(image) * 5
>
> And when you are done with it:
>
> Undefine, image
>
> (The UNDEFINE program can be found on my web page.)
>
> Otherwise, you continually get more and more process
> memory (with malloc), and there is no way to give it
> back.
>
> "Is it necessary?". Yes, it is very, very necessary. :-)
>
> Cheers,
>
> David
> --
> David W. Fanning, Ph.D.
> Fanning Software Consulting
> Phone: 970-221-0438, E-mail: david@dfanning.com
> Coyote's Guide to IDL Programming: http://www.dfanning.com/
> Toll-Free IDL Book Orders: 1-888-461-0155

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[Message index]

		Re: IDL Memory Leaks By: Myron Brown on Mon, 05 November 2001 13:58
		Re: IDL Memory Leaks By: David Fanning on Mon, 05 November 2001 13:21
		Re: IDL Memory Leaks By: Myron Brown on Mon, 05 November 2001 12:57
		Re: IDL Memory Leaks By: John-David T. Smith on Mon, 05 November 2001 10:24
		Re: IDL Memory Leaks By: David Fanning on Mon, 05 November 2001 10:22
		Re: IDL Memory Leaks By: John-David T. Smith on Tue, 06 November 2001 09:59
		Re: IDL Memory Leaks By: pit on Tue, 06 November 2001 07:15
		Re: IDL Memory Leaks By: Mark Hadfield on Mon, 05 November 2001 17:02
		Re: IDL Memory Leaks By: John-David T. Smith on Mon, 05 November 2001 14:22
		Re: IDL Memory Leaks By: Stein Vidar Hagfors H[1] on Tue, 06 November 2001 06:23
		Re: IDL Memory Leaks By: Jaco van Gorkom on Tue, 06 November 2001 05:16

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