[MITgcm-support] Adjoins advection schemes

[Matthew Mazloff]

And I'll add that the adjoint is usually run without multi-dimensional  
advection

GAD_OPTIONS.h:#define DISABLE_MULTIDIM_ADVECTION

If I remember correctly this is to prevent some nasty recomputations.

-Matt




On Jul 2, 2012, at 6:41 AM, Patrick Heimbach wrote:

>
> Christopher,
>
> our scheme of choice for the adjoint has become
> 3rd-order direct space and time DST3 in non-flux limited form, i.e.  
> scheme 30.
> DST3FL (33) causes problems for certain applications, and we haven't  
> followed up on this
> (the obvious issue being how the limiters are formulated).
>
> SOM is very memory-consuming, so we've staid away from this one for  
> the adjoint
> (which amplifies memory-consumption).
>
> OS7MP is also currently disabled but might be worth a try
> (would need some tweak though before it can be attempted).
>
> -Patrick
>
> On Jul 2, 2012, at 3:58 AM, Martin Losch wrote:
>
>> Christopher,
>>
>> the easiest way to find out is to have a look at gad_advection or  
>> gad_calc_rhs (the calls to GAD_*_ADV_X/Y). You'll see that most  
>> schemes "work" (i.e., they are allowed to be used) but in  
>> particular OS7MP (and I think SOM) doesn't work. From my experience  
>> I recommend using linear advection schemes (which rules out all  
>> flux limited schemes) for more accurate gradients.
>>
>> Martin
>>
>> On Jun 29, 2012, at 10:25 PM, Christopher L. P. Wolfe wrote:
>>
>>> Hi all,
>>>
>>> Does anyone know if there exists a list of advection schemes which  
>>> are known to "work" with adjoint? I'm particular interested in the  
>>> higher order schemes like OS7MP and SOM and their flux limited  
>>> forms.
>>>
>>> Thanks in advance,
>>> Christopher
>>>
>>>
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>>
>>
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> ---
> Patrick Heimbach | heimbach at mit.edu | http://www.mit.edu/~heimbach
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