Thanks, I monitored the ksp but I found that " unpreconditioned resid norm" and "true resid norm" are exactly the same. I can't understand while I set Jacobian = Precondition matrix ?!!!
In addition, I am solving true Newton iterations and I saw that first iteration is good (as I got from previous linear solvers) and the norm of the matrix is what I expected BUT for the next nonlinear iteration, the linear iterations can not converge to desired tolerance!!! On Tue, Oct 11, 2011 at 6:18 PM, Barry Smith <bsmith at mcs.anl.gov> wrote: > > http://www.mcs.anl.gov/petsc/petsc-as/documentation/faq.html#kspdiverged > > > On Oct 11, 2011, at 9:45 AM, behzad baghapour wrote: > > > Dear all, > > > > I set my Jacobian matrix in petsc and test it to ensure for correctness > for Jacobian and RHS function. ( also precondition = jacobian ) > > I have solved my problem before with some other solvers (gmers/ILU(2)) > and the convergence has been achieved within 15 - 16 iterations. > > > > But in petsc the linear solver (ksp=GMRES) is not converged within this > number ( or may be converged in more than 700 iterations!!! ). I know that I > should have a mistake but I can't predict it? > > > > Please help me what parts of petsc solver I should check? > > > > Regards, > > Behzad > > > > -- > > ================================== > > Behzad Baghapour > > Ph.D. Candidate, Mechecanical Engineering > > University of Tehran, Tehran, Iran > > https://sites.google.com/site/behzadbaghapour > > Fax: 0098-21-88020741 > > ================================== > > > > -- ================================== Behzad Baghapour Ph.D. Candidate, Mechecanical Engineering University of Tehran, Tehran, Iran https://sites.google.com/site/behzadbaghapour Fax: 0098-21-88020741 ================================== -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20111011/1cf18925/attachment.htm>
