[MITgcm-devel] stripes in adjoint along tile edges

[Torge Martin]

Hi Martin,

That looks a lot like the issue I had when I last tested the ITD code on a
linux cluster using 24 cpus. Now I remember talking to Patrick about the
possibility that the overlap regions might not be handled well in the ITD
code. Have to check this. Would be great to hear how you solve your issue
in the end.

Torge

On Thu, Nov 20, 2014 at 4:28 PM, Martin Losch <Martin.Losch at awi.de> wrote:

> Hi adjoint people,
>
> while debugging, I stumbled over interesting stripes in the adjoint fields
> along tile edges. See attached files for an example (based on arctic_cs36
> with 24 cpus, sNx = 35, sNy = 48), log10(sqrt(adU**2)) for layers 1 and 10
> after 1 adjoint timestep (after evaluating the cost function). As a cost
> function I evaluate theta(80,30), at the spot with the highest sensitivity.
> The stripes have low magnitudes (1e-8), but still large compared to the
> surrounding values. Does that look familiar in any way? Should I be worried
> about this? (I am because the model later explodes along these stripes).
>
> Martin
>
> PS. I am using cdTargetResidual=1e-13 and cg2dMaxIters=1000, and these
> stripes appear when the seaice package is turned off totally (forwards and
> backwards), with advection scheme 30 and 33 for T/S.
>
>
>
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>
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