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Re: Inconsistent Mean Calculation [message #30837 is a reply to message #30836]

Mon, 20 May 2002 18:59

Kenneth P. Bowman
Messages: 585
Registered: May 2000

Senior Member

In article <a3589d11.0205201557.1a92499f@posting.google.com>,
plmcelwee@yahoo.com (Phil) wrote:

> I have 5000 frames of video in a NetCDF file, and I want to calculate
> the average of frame 2557. I have read the video file into both IDL
> v5.1 and
> Matlab v6.1. Additionally I have extracted frame 2557 and copied it
> into Excel. Here are the mean calculations I get for this frame:
>
> Matlab: 4092.6805
> Excel: 4092.6805
> IDL: 4093.6165
>
> Can anyone offer any suggestions as to why the IDL calculation is
> different? Maybe there is a bug in IDL 5.1? Yeah I know it's a
> really old version. :)

Excel is doing the calculation in double precision; Matlab probably
likewise. Try TOTAL(image, /DOUBLE)/n or MOMENTS(image, /DOUBLE) in IDL
and let us know what you get.

5.1 is really old? Oh, maybe it's me that's really old.

Ken

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[Message index]

		Re: Inconsistent Mean Calculation By: plmcelwee on Tue, 21 May 2002 10:39
		Re: Inconsistent Mean Calculation By: Mark Hadfield on Mon, 20 May 2002 18:00
		Re: Inconsistent Mean Calculation By: Kenneth P. Bowman on Mon, 20 May 2002 18:59

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