[MITgcm-support] changing the number of tiles

[Stephanie Dutkiewicz]

Paola -
I usually join the files with the script:
utils/script/joinmds

> joinmds pickup 0000003200


steph

On Tue, 7 Mar 2006, Paola Cessi wrote:

> Hi Jean-Michel, is the step of reassembling the pickup files into a single 
> file necessary? I am asking because I cannot do it in Matlab, given the size 
> of my files. Do you have an alternative suggestion that is not as memory 
> intensive? Thanks,
>
> paola
>
> On Wed, 1 Mar 2006, Jean-Michel Campin wrote:
>
>> Hi Paola,
>> 
>> The thing that I do generally, in this case, is to read
>> all the tile-files (in matlab, with rdmds), and then
>> I just write the output from rdmds to a binary file:
>> 
>> namfil='pickup.0000003200';
>> va=rdmds(namfil);
>> wrfile=[namfil,'.data'];
>> fid=fopen(wrfile,'w','b');
>> fwrite(fid,va,'real*8');
>> fclose(fid);
>> 
>> And there is no problem for the model to restart from a unique file,
>> i.e. a "global" file that contains all the tiles, whatever the
>> new domain decomposition is.
>> 
>> Jean-Michel
>> 
>> On Wed, Mar 01, 2006 at 07:46:46PM -0500, Baylor Fox-Kemper wrote:
>>> No interpickups isn't necessary if there is no interpolation or
>>> coarsening, but it will work in that case, too.
>>> 
>>> What Ed is suggesting (I think) doesn't require netcdf.  However,
>>> someone not using netcdf should spell out exactly how this is to be
>>> done.  I think usually one needs to keep the number of tiles fixed,
>>> while changing the number of processors.  However, this process
>>> seemed messy to me, so that's why I wrote interpickups in the first
>>> place.
>>> 
>>> Will someone please explain how to do retiling, or at pickup
>>> conversions (without cubed sphere complications is fine) in the
>>> pickups for posterity?
>>>   -Baylor
>>> 
>>> 
>>> On Mar 1, 2006, at 5:49 PM, Paola Cessi wrote:
>>> 
>>>> Is interpickups.m necessary if the number of gridpoints is the
>>>> same, and thus no interpolation is needed, but the tiling changes?
>>>> paola
>>>> 
>>>> On Wed, 1 Mar 2006, Baylor Fox-Kemper wrote:
>>>> 
>>>>> Hi Paola,
>>>>> There is a little program: utils/matlab/interpickups.m, that I
>>>>> wrote a while back (and I think works with the present version of
>>>>> the code).  It takes a bunch of mnc input pickup files with one
>>>>> tiling and a bunch of mnc output pickup files with a different
>>>>> tiling, and interpolates between them in a simple way.  This way
>>>>> you can coarsen or fine-grain a set of pickup files to restart
>>>>> with a different tiling or even a different resolution.  If the
>>>>> number of gridpoints in the input and outputs is the same, it
>>>>> shouldn't change the data at all, it should just copy it
>>>>> appropriately from the input files to the outputs.
>>>>> The easy way to get the output pickups is to set up the model
>>>>> with the new gridding and run for one timestep outputting a
>>>>> pickup.  The routine will then overwrite the data in the files
>>>>> with the interpolated data from the set of input files.
>>>>> Cheers,
>>>>>   -Baylor
>>>>> 
>>>>> 
>>>>> 
>>>>> On Mar 1, 2006, at 2:47 PM, Paola Cessi wrote:
>>>>> 
>>>>>> Is it possible to restart a computation with 4*N tiles, using the
>>>>>> pickup files generated with N tiles, while keeping Nx and Ny
>>>>>> fixed? In other words, is it possible to change nPx and nPy in a
>>>>>> restart run, while keeping Nx and Ny the same? (without using
>>>>>> netcdf)
>>>>>> paola
>>>>>> --------------------------------------------------------------------
>>>>>> -----
>>>>>> Paola Cessi                            Tel: +1 858 534 0622
>>>>>> Scripps Institution of Oceanography    Fax: +1 858 534 8045
>>>>>> 9500 Gilman Drive
>>>>>> UCSD-0213                              e-mail: pcessi at ucsd.edu
>>>>>> La Jolla, CA 92093-0213
>>>>>> USA                      Web:  http://www-pord.ucsd.edu/~pcessi
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>>>>> 
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