[MITgcm-devel] code changes

[Matthew Mazloff]

Hello,

The ordering for obcs controls is T / S / normal vel /  tangential  
vel.  This is consistent throughout the code

-Matt


On Mar 10, 2011, at 9:22 AM, Holly Dail wrote:

>>> Hate to open other cans of worms, but there is some inconsistency  
>>> in the code re. the ordering of obcs control fields.  I believe  
>>> the code pieces I'm using assume the 3rd field is vvel and 4th  
>>> field is uvel (i.e. they are packed T/S/V/U -- see for example  
>>> ctrl_getobcss.F where OBSu is modified when iobcs is 4), while  
>>> code like cost_obcsvol.F assumes they are packed T/S/U/V (which is  
>>> more logical, but this code is never called from any other S/R).   
>>> I can't figure out right now which order they are packed into the  
>>> control files.  I'm mostly concerned as to whether its all  
>>> consistent, rather than whether its illogical.
>> I can only recommend to avoid code within #ifdef  
>> ALLOW_CTRL_OBCS_BALANCE. The code does not look right to me. I  
>> think Jake tried to balance both normal and tangential  
>> xx_velocities (why?) and might have mixed up things? Plus, there  
>> are definitely hfac's missing in this computation, so leave it  
>> alone. The ordering is T/S/U/V for the obcs and this is also true  
>> for the ctrl-fields.
>> For balanced flow even with optimized boundary flow you can  
>> (probably) use the "forward" flags OBCSuseBalance with all the new  
>> features checked in by Jean-Michel. I am currently using an older  
>> hacked version which does effectively what Jean-Michel implemented  
>> more generally, and this gives fine results (in terms of balancing).
>
> I'm attaching the relevant bits from ctrl_getobcss.F in which I  
> believe the ordering is T/S/V/U:
>
>            else if (iobcs .EQ. 4) then
>             OBSu(i,k,bi,bj) = OBSu (i,k,bi,bj)
>     &            + obcssfac            *xx_obcss0(i,k,bi,bj,iobcs)
>     &            + (1. _d 0 - obcssfac)*xx_obcss1(i,k,bi,bj,iobcs)
>             OBSu(i,k,bi,bj) = OBSu(i,k,bi,bj)
>     &            *maskW(i,j,k,bi,bj)
>            else if (iobcs .EQ. 3) then
>             OBSv(i,k,bi,bj) = OBSv (i,k,bi,bj)
>     &            + obcssfac            *xx_obcss0(i,k,bi,bj,iobcs)
>     &            + (1. _d 0 - obcssfac)*xx_obcss1(i,k,bi,bj,iobcs)
>             OBSv(i,k,bi,bj) = OBSv(i,k,bi,bj)
>     &            *maskS(i,j+jp1,k,bi,bj)
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