[MITgcm-support] Equatorial Channel from -70 degree to +70 degree

[Yuan Lian]

Hi, Jean-Michel,

Good to hear from you again. I will follow your tips to run the 
simulations again. I also have one question about adjusting the location 
of cube-sphere-grid corners. Could you please give me some intructions 
to do it? Thanks!

cheers,
Yuan

Jean-Michel Campin wrote:

>Hi Yuan,
>
>Currently, the zonal filter only works with no tile
>decomposition (i.e. single tile) in the X direction.
>If you want to use it in your set-up, you will need
>to find the 8 tiles in the Y direction (e.g.:
>increasing Ny to 96 and setting nPy=8, nSy=12, 
>keeping nSx=256)
>
>Jean-Michel
>
>  
>
>>Hi, Dimitris and Martin,
>>
>>I just figured out that the problem is actually caused by zonal filter. 
>>I thought I shoud apply zonal filter if the latitude is greater than 45 
>>degree. Once the zonal filter was turned off, the code just ran 
>>smoothly. I feel a little uncomfortable that I have to turn off zonal 
>>filter. This might cause problems when the channel is close to polar 
>>region, say, a channel from -80 degree to +80 degree. However I think I 
>>can just reduce time step if the zonal filter is turned off.
>>
>>Yuan
>>
>>Martin Losch wrote:
>>
>>    
>>
>>>Yuan,
>>>
>>>the results from
>>>nPx=8, sNx=32, sNy=93 should be exactly the same (except for round- 
>>>off error) as those from
>>>nPx=4, sNx=64, sNy=93,
>>>nPx=2, sNx=128, sNy=93, and
>>>nPx=1, sNx=256, sNy=93, regardless of time step.
>>>When you have NaN's in one case and no NaN's in another, then  
>>>something else is wrong. What about your nSx/nSy? both should be 1 in  
>>>all of these examples so that  sNx*nSx*nPx = 256, and sNy*nSy*nPy =  
>>>93 for all cases.
>>>
>>>Martin
>>>
>>>On 4 Oct 2006, at 08:29, Yuan Lian wrote:
>>>
>>>      
>>>
>>>>Hi, Dimitris,
>>>>
>>>>Thanks. I tried the configuration nPx=8, sNx=32, sNy=93 but the  
>>>>simulation gave NAN values. I had to reduce the number of grids in  
>>>>latitude. The configuration nPx=4, sNx=64, sNy=63 worked just fine.  
>>>>I will try nPx=4, sNx=64, sNy=93 and see how it works. I might try  
>>>>to use very short time step as well.
>>>>
>>>>cheers,
>>>>Yuan
>>>>
>>>>Dimitris Menemenlis wrote:
>>>>
>>>>        
>>>>
>>>>>Hi Yuan,
>>>>>
>>>>>          
>>>>>
>>>>>>I noticed that, in order to run the simulation, the number of  grid 
>>>>>>points in
>>>>>>X direction has to be greater than the number of grids in Y  
>>>>>>direction in a
>>>>>>single tile.
>>>>>>            
>>>>>>
>>>>>
>>>>>There is no such restriction as far as possible model  
>>>>>configurations are concerned.
>>>>>
>>>>>          
>>>>>
>>>>>>The number of grids is 256x93
>>>>>>So the question is: how to configure the "SIZE.h" to run the  
>>>>>>simulation with
>>>>>>4 or 8 processors?
>>>>>>            
>>>>>>
>>>>>
>>>>>Since 93 is not divisible by 2, and assuming you are using MPI,   
>>>>>you can have
>>>>>nPx=4, sNx=64, sNy=93 and
>>>>>nPx=8, sNx=32, sNy=93.
>>>>>
>>>>>Cheers, Dimitris
>>>>>
>>>>>_______________________________________________
>>>>>MITgcm-support mailing list
>>>>>MITgcm-support at mitgcm.org
>>>>>http://mitgcm.org/mailman/listinfo/mitgcm-support
>>>>>
>>>>>          
>>>>>
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>>>>
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>>>      
>>>
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