Re: Question about addfile command

Hi Gareth!

The NCL team will probably have a better idea, but one possibility is if
your file has an unlimited dimension (usually time). In that case, NCL has
to read in the whole file to see how big it really is. After you open the
file the first time, the computer will remember the size for at least a few
minutes, so subsequent addfiles should be faster.

Hope this helps...

     Carl

On Wed, Dec 8, 2010 at 10:47 PM, Gareth Berry <gareth@atmos.albany.edu>wrote:

> Hello!
>
> I have a quick question about the addfile command: I've been reading
> some large (1.7Gb) grib files in a plotting script and it's become
> apparent that the addfile command is taking an outstandingly long time
> to execute. I'm curious as to whether they is a way to speed up the
> process of opening a grib file?
>
> I'm using files from a local server via an nfs mount - from my network
> traffic I noticed that ncl transfers an amount of data about equal in
> size to the file itself. I would of assumed that addfile would not
> transfer this amount of data. I'm using ncl 5.2.1 on MacOSx 5.8, but
> have experienced the same issues with ncl 5.1.1. I don't think the nfs
> mount is the culprit as the long wait is not reduced significantly if
> I run using a file stored on my machine (both take ~1 min to read 1.7
> Gb). Any help or suggestions are most welcome!
>
> Cheers,
>
> Gareth.
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-- 
Carl J. Schreck III, PhD
Postdoctoral Research Associate
Cooperative Institute for Climate and Satellites (CICS-NC)
NOAA's National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801
Tel: 828-257-3140
carl.schreck@noaa.gov
http://www.atmos.albany.edu/student/carl/

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Received on Thu Dec 9 04:54:29 2010