Dear Dr.Bangerth, I tried both, first I tried 1e-4*system_rhs.l2_norm(), it failed. Then I tried with exact precision limits, from 1e-3 to 1e-8, all of them cannot converge. If I set the precision level as 1e-4, with or without L2 norm it stopped at step-42 with the residue 0.0113395. Best regards, Yuesu
On Sun, Aug 16, 2020 at 7:20 PM Wolfgang Bangerth <[email protected]> wrote: > On 8/14/20 9:20 PM, yuesu jin wrote: > > I tried a few levels of the tolerance, 1e-3, 1e-4 ,1e-6 and 1e-8. 1e-3 > > converged because that is in the same level with the solution. Error > occurs > > below 1e-4. I have tried the Jacobi preconditioner instead of SSOR in > the > > single thread CG version, it converged as well. > > Is this 1e-4 * system_rhs.l2_norm(), or just 1e-4? If the latter, what is > the > size of system_rhs.l2_norm()? You should choose a tolerance that is > proportional to the norm of the right hand side. > > Best > W. > > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: [email protected] > www: http://www.math.colostate.edu/~bangerth/ > > -- > The deal.II project is located at http://www.dealii.org/ > For mailing list/forum options, see > https://groups.google.com/d/forum/dealii?hl=en > --- > You received this message because you are subscribed to the Google Groups > "deal.II User Group" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/dealii/0cd8b66f-b168-c725-200f-b2bb6ff727d5%40colostate.edu > . > -- Yuesu Jin, Ph.D student, University of Houston, College of Natural Sciences and Mathematics, Department of Earth and Atmospheric Sciences, Houston, Texas 77204-5008 346-404-2062 -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/CA%2B25a%3DKGEYe-3RyZEi8Kn60UbAUROHj9iiqV7mYiZQBYiDuxBQ%40mail.gmail.com.
