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Re: IDL, arrays, and memory [message #33897 is a reply to message #33896]

Tue, 04 February 2003 09:31

Sean Raffuse
Messages: 46
Registered: July 2001

Member

>
> However, whereas in C the difference in terms of speed and algorithm
> design is negligible between using a ragged array and a "wasteful"
> full 3D array, this is not true in IDL. In particular, you can't use
> most of IDL's fast array-based operators with an array of pointers;
> you're stuck accessing each element in a loop, which will be markedly
> slower for a data structure of this size.
>
> You must balance the memory saved against the speed and flexibility
> with which you can operate on the data. This is a common theme in
> IDL, which, in many instances, trades increased memory usage for
> greater speed of execution. Often you can find other ways to organize
> the data which reduces the memory footprint while preserving much of
> the same flexibility had by putting it all in a single array. Or you
> can use, e.g., NaN values to fill the "wasted" array elements and
> avoid having to treat them specially.
>
> Good luck,
>
> JD

Exactly what I needed to hear. Speed of execution is indeed a major issue
here. I'll stick with the big array.

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[Message index]

		Re: IDL, arrays, and memory By: James Kuyper on Tue, 04 February 2003 09:29
		Re: IDL, arrays, and memory By: Sean Raffuse on Tue, 04 February 2003 09:31
		Re: IDL, arrays, and memory By: JD Smith on Tue, 04 February 2003 09:23
		Re: IDL, arrays, and memory By: David Fanning on Tue, 04 February 2003 08:54

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