[MITgcm-support] XYPeriodicity

[Gianmaria Sannino]

Dear Martin,

I agree with you that the model needs to exchange the obcs 
(and the other variables) through adjacent overlapping. 
The problem is that MITgcm tends to exchange the variables 
also when you are running on one CPU exchanging in this 
way your eastern end overlapping region variables on the 
western end region and viceversa. This is evident for 
example during one of the first exchange, i.e. during the 
exchange of bathymetry in ini_depth.F where it copies the 
eastern bathymetry on the western overlapping region and 
viceversa.

This is because when MITgcm assigns the identifiers to 
each tile and then defines a map of neighbors for each 
tile in ini_communication_pattern.F it assigns, when uses 
one CPU, the eastern side at the western side (and 
viceversa).

Is there a flag to define/undefine to avoid this kind of 
problems?

thanks in advance
gianmaria

On Thu, 2 Mar 2006 08:56:55 +0100
  Martin Losch <mlosch at awi-bremerhaven.de> wrote:
>Hallo Gianmaria,
>
>that's the way it is supposed to be, the obcs-pkg should 
>overwrite  these values in the overlaps if necessary (it 
>works for me with four  open boundaries).
>
>Martin
>On Feb 27, 2006, at 10:53 AM, Gianmaria Sannino wrote:
>
>>
>>
>> Hello,
>>
>>
>>
>> I’m trying to set a channel experiment with a real 
>>bathymetry and  
>> two open boundaries on the eastern and western side. The 
>>experiment  
>> runs on an alpha monoCPU and this is my SIZE.h:
>>
>>
>>
>>       PARAMETER (
>>
>>      &           sNx =  128,
>>
>>      &           sNy =  90,
>>
>>      &           OLx =   3,
>>
>>      &           OLy =   3,
>>
>>      &           nSx =   1,
>>
>>      &           nSy =   1,
>>
>>      &           nPx =   1,
>>
>>      &           nPy =   1,
>>
>>      &           Nx  = sNx*nSx*nPx,
>>
>>      &           Ny  = sNy*nSy*nPy,
>>
>>      &           Nr  =  42)
>>
>>
>>
>> It seems that in this configuration (MPI is off) in the 
>>eastern  
>> overlapping region there are data from the western side 
>>and  
>> viceversa, in other words it seems that it is working a 
>>sort of  
>> Xperiodicity.
>>
>> I’ve seen that in ‘ini_communication_patterns’ one can 
>>set
>>
>>
>>
>>       notUsingXPeriodicity       = .TRUE.
>>
>>       notUsingYPeriodicity       = .TRUE.
>>
>>
>>
>> but also in this case I still have periodicity.
>>
>>
>>
>> Anyone could help me?
>>
>>
>>
>> Ciao
>>
>> gianmaria
>>
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>
>
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******************************************************
Gianmaria Sannino   
ENEA (Italian Agency for Energy and Environment)
Climate Project - Ocean Modelling Unit 
SP 91 - via Anguillarese 301
S.M. di Galeria, 00060 ROMA, ITALY
Voice: (+39) 06 3048 6799   Fax: (+39) 06 3048 4264
e-mail: gianmaria.sannino at casaccia.enea.it
URL: http://clima.casaccia.enea.it/staff/sannino/
******************************************************