minor tweaks and parameter changes #39
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Do you need this fixed at 16? The thing is that for FT we need to keep this free, otherwise we cannot estimate the overhead..
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No, you can set this to whatever value you want. The only problem is that with too few iterations, PFASST can become unstable over the course of the simulation.
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OK, so PFASST will reasonably converge with the residual criterion?
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In general, yes. You might have to tweak the tolerance a bit, PFASST takes quite long to reach very fine residuals. I tried to go for something between 1e-5 and 1e-6. The residual after the first iteration is already 1e-4, so larger values do not make much sense.
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What would be a reasonable tolerance to get approx. 10-20 iterations per block, then? Does this change during the simulation or is it more or less constant?
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Try 1e-6 or 1e-7... for 16 processors, this might already give you quite a lot of iterations. It seems not to change too much over the simulation, but I did not take a systematic look at it.
minor tweaks and parameter changes
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Minor changes and fixed parameters. Now runs PFASST with 16 processors - alas, ultimately the last process needs 16 iterations to converge.