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Re: Array Subscripting Memory Usage (watch out!) [message #32415 is a reply to message #32328]

Thu, 03 October 2002 03:55

R.Bauer
Messages: 1424
Registered: November 1998

Senior Member

Dick Jackson wrote:

> Hi all,
>
> This may be old news to some of you, but it surprised me and a couple of
> colleagues, and I couldn't find any discussion of it on this group, so
> I'll share it around.
>
> I was surprised to find how much memory is used during access to a
> subset of an array. I ran this, which makes a 1000x1000 array, and
> accesses a subset of it using an array of subscripts:
>
> a = bindgen(1000, 1000)
> subscripts = Long(RandomU(seed, 500)*1000)
> baseMem = (memory())[0]
> help, a[subscripts, *]
> highWaterMem = (memory())[3]
> Print, 'Memory used during access: ', highWaterMem-baseMem

That's normal.
If you need a constant you need memory for it in it's type multiplied by
it's length.

I would be interested how this is handled?
a = (bindgen(1000, 1000))[Long(RandomU(seed, 500)*1000),*]

regards

Reimar

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email: R.Bauer@fz-juelich.de
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[Message index]

		Array Subscripting Memory Usage (watch out!) By: Dick Jackson on Wed, 02 October 2002 14:28
		Re: Array Subscripting Memory Usage (watch out!) By: JD Smith on Fri, 04 October 2002 13:58
		Re: Array Subscripting Memory Usage (watch out!) By: Dick Jackson on Fri, 04 October 2002 13:13
		Re: Array Subscripting Memory Usage (watch out!) By: R.Bauer on Fri, 04 October 2002 12:40
		Re: Array Subscripting Memory Usage (watch out!) By: R.Bauer on Thu, 03 October 2002 03:55
		Re: Array Subscripting Memory Usage (watch out!) By: R.Bauer on Thu, 03 October 2002 03:49

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