Re: [netcdfgroup] Per variable chunking with nccopy

• To: Charlie Zender <zender@xxxxxxx>
• Subject: Re: [netcdfgroup] Per variable chunking with nccopy
• From: Chris Barker <chris.barker@xxxxxxxx>
• Date: Tue, 13 Jan 2015 08:34:31 -0800

On Mon, Jan 12, 2015 at 8:19 PM, Charlie Zender <zender@xxxxxxx> wrote:

> NCO version 4.4.7 (and later) implement the Rew chunking algorithm:
>
> ncks -4 --cnk_plc=all --cnk_map=rew in.nc out.nc
>
> http://nco.sf.net/nco.html#cnk
> The C-code is in nco_cnk.c.
>
> NCO only utilizes this algorithm for 3D variables.
> 4D variables in the same file will not be chunked by this algorithm,
> though NCO will preserve their chunking from a previous algorithm.
>
> We're open to suggestions on how to make this more usuable.
> One idea would be to make, in NCO-speak, a chunk policy that
> uses 'rew' chunk map for 3D vars, and something else for other ranks.
>

indeed -- a reasonable default chunking for any dimension variable would be
good (even though it is, indeed, impossible to define the "best" one
without knowing the use-cases)

-Chris

-- 

Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
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Chris.Barker@xxxxxxxx

• References:
  • Re: [netcdfgroup] Per variable chunking with nccopy
    • From: Charlie Zender