[MITgcm-devel] stripes in adjoint along tile edges

[Menemenlis, Dimitris (329D)]

Not sure if relevant, but I do remember that Ralf Giering was sufficiently concerned about cg2d inaccuracies to write an alternative "direct" solver during his time at JPL.

One way to test this hypothesis would be to vary (lower or raise) the accuracy (number of iterations) of the cg2d solver and observe whether striping decreases or increases.

> On Nov 27, 2014, at 6:37 AM, Martin Losch <Martin.Losch at awi.de> wrote:
> 
> Hi there,
> 
> since there hasn’t been any other statement: Can I assume that no-one on this list has ever seen stripes like this in the adjoint (would be good, because it would mean, that I am making a mistake, that I should be able to find)? Or does the low reply rate mean that no-one has ever looked closely enough to see the stripes? 
> 
> I am running a little out of ideas about where they might come from. I have a suspicion, that they are related to cg2d/solve_for_pressure, but no good pieces of evidence, yet.
> 
> Martin