OK, but libMesh calls a library, defaulting to PETSc if it's installed. Which library are you using?
PETSc-3.3 On Thu, May 22, 2014 at 10:58 AM, Paul T. Bauman <[email protected]> wrote: > On Thu, May 22, 2014 at 11:52 AM, walter kou <[email protected]>wrote: > >> The amount of relative change in terms of ||delta U|| is about 1.0e-6 for >> my case with only 8 nodes. That's why I doubt I may not setup the solver >> correctly. >> >> >> If an iterative solver, what's the tolerance? >> >> Are you asking how I solved x in Ax=b? >> > > Yes. > > >> >> I just assembled the system: >> {system.matrix->add_matrix (Ke, dof_indices); >> system.rhs->add_vector (Fe, dof_indices);} >> then called system.solve, where system is a >> <TransientLinearImplicitSystem>. >> > > > > >> I did use the tolerance for the loop of iteration solver. it was 1.0e-5 >> for the delta U, and the n-iteration-number = 1000; >> > > This explains why you see 1.0r-6 in \Delta U - your > OK, but libMesh calls a library, defaulting to PETSc if it's installed. > Which library are you using? > > PETSc-3.3 > tolerance was 1.0e-5 (as stated above) > > > >> The above mainly shows the difference of the first >> iteration/calculation(Ax=b) between one processor and two processors. >> > > Right, the residual difference was < 1.0e-10 difference (small) and within > tolerance on \Delta U. > > >> By the way, What is the typical parameter setup I should use for the >> iterative solver? >> > > Entirely problem dependent. > > ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
