[petsc-users] Convergence behavior of different solvers

[Alexander Grayver]

Ok, thank you for pointing me to this paper.

On 21.03.2012 11:38, Jed Brown wrote:
> On Wed, Mar 21, 2012 at 04:03, Alexander Grayver 
> <agrayver at gfz-potsdam.de <mailto:agrayver at gfz-potsdam.de>> wrote:
>
>     Hello,
>
>     Plotting values of relative residual norm versus iteration I
>     noticed that these curves have different behavior. For instance,
>     ones I got with BiCGStab are oscillatory and rather noisy with
>     large jumps within few iterations. Curves for QMR are smooth,
>     however it's usual that they stagnate for ~10-20 iterations and
>     then go down further. Same preconditioner is applied for both and
>     both methods are Lanczos based, so I don't understand this.
>     I'm wondering is this just my specific case or there is general
>     explanation for that?
>
>
> This is normal.
>
> http://people.maths.ox.ac.uk/trefethen/publication/PDF/1992_52.pdf


-- 
Regards,
Alexander

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