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Re: moving average of a large array [message #51499 is a reply to message #51487]

Thu, 23 November 2006 19:58

Kenneth P. Bowman
Messages: 585
Registered: May 2000

Senior Member

In article <1164296828.559622.31580@m7g2000cwm.googlegroups.com>,
"Jenny" <envi35@yahoo.ca> wrote:

> Hi, I want to calculate the moving average of a large array:
> data[800,800,365]. The moving average is for the 3rd dimension - day of
> year. But TS_SMOOTH only works for a vector. Anyone knows if there is
> another function in IDL that I could use? I probably can use TS_SMOOTH
> and for loops to get this, but it will be slow. In addition, there are
> invalid data in my array as well.
>
> I've read discussions in this list about adding Dimension and NAN
> keywords to other functions, such as Total, Median, etc., which are
> very useful. Why nobody cares about TS_SMOOTH? Or am I asking a silly
> question? Is there an obvious way to calculate the moving average of a
> large array?
>
>
> Thanks,
> Jenny

If x = FLTARR(800, 800, 365)

try

y = SMOOTH(x, [1, 1, 3])

This runs a boxcar smoother, which has awful spectral characteristics.
You also might want to consider what to do at the edges.

Ken Bowman

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[Message index]

		Re: moving average of a large array By: Paul Van Delst[1] on Mon, 27 November 2006 09:21
		Re: moving average of a large array By: David Fanning on Fri, 24 November 2006 08:30
		Re: moving average of a large array By: David Fanning on Fri, 24 November 2006 08:27
		Re: moving average of a large array By: envi35@yahoo.ca on Fri, 24 November 2006 08:17
		Re: moving average of a large array By: David Fanning on Fri, 24 November 2006 07:08
		Re: moving average of a large array By: envi35@yahoo.ca on Fri, 24 November 2006 06:46
		Re: moving average of a large array By: Kenneth P. Bowman on Thu, 23 November 2006 19:58
		Re: moving average of a large array By: David Fanning on Mon, 27 November 2006 09:32

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