Re: [deal.II] PETSc iteration does not converge

2020-08-17 Thread yuesu jin
OK, I see. I will do it, thank you! I will let you know if I get any result. On Mon, Aug 17, 2020 at 7:06 PM Wolfgang Bangerth wrote: > On 8/17/20 6:01 PM, yuesu jin wrote: > > I did nothing to verify those properties. because the single thread > CG > > solver converged well. I used

Re: [deal.II] PETSc iteration does not converge

2020-08-17 Thread Wolfgang Bangerth
On 8/17/20 6:01 PM, yuesu jin wrote:     I did nothing to verify those properties. because the single thread CG solver converged well. I used  different preconditioners in parallel version and single thread version. In the parallel version I used block Jacobi and in the single thread version

Re: [deal.II] PETSc iteration does not converge

2020-08-17 Thread yuesu jin
Dear Dr.Bangerth, I did nothing to verify those properties. because the single thread CG solver converged well. I used different preconditioners in parallel version and single thread version. In the parallel version I used block Jacobi and in the single thread version I used Jacobi. How can I

Re: [deal.II] PETSc iteration does not converge

2020-08-17 Thread Wolfgang Bangerth
   I tried both, first I tried 1e-4*system_rhs.l2_norm(), it failed. Then either the matrix is not symmetric/positive definite/whatever other property your iterative solver requires, or your preconditioner is unsuitable. What have you don to verify that your matrix has the necessary

Re: [deal.II] PETSc iteration does not converge

2020-08-16 Thread yuesu jin
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

Re: [deal.II] PETSc iteration does not converge

2020-08-16 Thread Wolfgang Bangerth
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

Re: [deal.II] PETSc iteration does not converge

2020-08-14 Thread yuesu jin
Dear Dr. Bangerth, 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. Best

Re: [deal.II] PETSc iteration does not converge

2020-08-14 Thread Wolfgang Bangerth
On 8/14/20 5:53 PM, yuesu jin wrote: I also wrote a single thread CG version, which converges well. The preconditioner in the parallel version is blockJacobi but the single thread version I used is SSOR. Does it matter to the convergence? Thank you! Yes, in exactly the ways the error

[deal.II] PETSc iteration does not converge

2020-08-14 Thread yuesu jin
Dear all, I am working on acoustic wave simulation through PETSc wrapper, it gives the error message: ** Mesh Info Dimensions2 No.cells:5144 Number of active cells:5144 Number of degrees of freedom:20833