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Re: speed of n_elements [message #17662 is a reply to message #17650]

Wed, 03 November 1999 00:00

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

Pavel Romashkin <promashkin@cmdl.noaa.gov> writes:
> So, briefly: if you want to get the size of an array of structures,
> examine the size of an array of scalar fields (if available) and you
> will have 10X5 faster n_elements.

Two things:

* I can't repeat your experience on Sun or Linux. On both those
machines n_elements(data.flag) is much slower than n_elements(data),
at least in a loop.

* I've always found that putting large data arrays into structures is
a big loser. In my experience it's slow to create such structures
and slow to extract the fields later. Thus I was surprised by your
observation (but unfortunately I can't confirm it); however because
of that I still avoid large arrays in structures. Use pointers or
handles instead.

Craig

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Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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[Message index]

		Re: speed of n_elements By: R.Bauer on Thu, 04 November 1999 00:00
		Re: speed of n_elements By: Craig Markwardt on Wed, 03 November 1999 00:00
		Re: speed of n_elements By: Pavel Romashkin on Wed, 03 November 1999 00:00
		Re: speed of n_elements By: Craig Markwardt on Wed, 03 November 1999 00:00

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