Hi Alexander, The versions of library I am using are listed below: deal.II 8.4.0 petsc 3.3.0.3 MUMPS 4.10.0-p3 I run the first two mesh refining loops of the step-17. So the matrix size is 162*162 and 302*302 respectively. The symmetry direct solver doesn't give the 'right solution' for both cases.
Sorry, I am not familiar with the petsc library. You meant if I call *solver.solve(system_matrix,solution,system_rhs)* twice, internally, it would use the factorization from the first time for the second solving process? (of course the system matrix is the same.) Do i understand this correctly? Thanks. Best, Shanglong 在 2016年7月25日星期一 UTC-4下午3:24:25，Alexander写道： > > >> I modify the step-17 so that it uses PETScWrappers::SparseDirectMUMPS as >> solver. However, when I active the option of set_symmetric_mode, the >> solution has discrepancy from CG or MUMPS without the symmetry option. (The >> solutions from CG and MUMPS without symmetry option are identical though.) >> Any suggestion? >> > > Which version of PETSc, MUMPS and deal.II do you use? What is the matrix > size you work with? > > >> >> And it seems to me that PETScWrappers::SparseDirectMUMPS doesn't have >> the functionality of reusing the factorization of system matrix for >> different right-hand side vector. Do I miss anything? >> > > Yes, it does. The first time you call solve it performs factorization, but > the following calls will reuse it (since you don't call KSPSetOperators). > > >> >> Thank you very much. >> >> Best, >> Shanglong >> > -- 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]. For more options, visit https://groups.google.com/d/optout.
