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Re: The continuing saga of WHERE and 2D [message #34312 is a reply to message #34243]

Fri, 28 February 2003 11:52

JD Smith
Messages: 850
Registered: December 1999

Senior Member

On Fri, 28 Feb 2003 11:15:11 -0700, Pavel Romashkin wrote:

> Hi JD,
> Is the same kind of allocation taking place when one simply calls
> FLTARR? I bet yes.
> I am still puzzled by the fact I can allocate 1.25 times more in the
> form of pointer arrays than as a single large array, like
>
> a = FLTARR(290000000) ; This is the limit, out of RAM over this (1.32
> Gb) a = PTRARR(3600, /allocate)
> temp = FLTARR(100000)
> for i = 0, 3599 do *a[i] = temp ; No problem at all
>

I'd go with the fragmentation argument. If so, this should be
independent of pointer use. You could, e.g., assign a different
variable name to each small array (execute comes to mind). The
system's memory allocator might not be pleased to give you a single
chunk of 1.32GB, but still be happy to hand out 100 chunks of 13.2 MB.

What if you repeat this a series of times, gradually reducing the
number of pointers to 1, while preserving the total memory allocated?
I'd bet it would slowly converge on the single-block limit, with fits
and starts as you pass awkward memory sizes.

JD

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[Message index]

		The continuing saga of WHERE and 2D By: Sean Raffuse on Thu, 27 February 2003 12:37
		Re: The continuing saga of WHERE and 2D By: David Fanning on Sun, 02 March 2003 16:24
		Re: The continuing saga of WHERE and 2D By: JD Smith on Fri, 28 February 2003 11:52
		Re: The continuing saga of WHERE and 2D By: Paul Van Delst[1] on Fri, 28 February 2003 10:42
		Re: The continuing saga of WHERE and 2D By: David Fanning on Fri, 28 February 2003 10:41

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