Hermes, Sorry, I don't use petsc. Maybe someone else can help you.
Best, Bruno Le lun. 14 mars 2022 à 05:42, Hermes Sampedro <[email protected]> a écrit : > Dear Bruno, > > I have been reading the examples and documents you pointed out. I tried to > use SolvereGREMS with PreconditionILU. However, I am getting a running > error that I can not really understand when calling > PETScWrappers::PreconditionILU preconditioner(system_matrix). However, it > seems to work with PETScWrappers::PreconditionBlockJacobi > <https://dealii.org/current/doxygen/deal.II/classPETScWrappers_1_1PreconditionBlockJacobi.html> > preconditioner(system_matrix). The solver function ad error that I get is > the following: > > *void LaplaceProblem<dim>::solve()* > > * {* > > * PETScWrappers::MPI::Vector > completely_distributed_solution(locally_owned_dofs,mpi_communicator);* > > * SolverControl cn(completely_distributed_solution.size(), 1e-8 * > system_rhs.l2_norm());* > > * PETScWrappers::SolverGMRES solver(cn, mpi_communicator);* > > * PETScWrappers::PreconditionILU preconditioner(system_matrix);* > > * solver.solve(system_matrix, completely_distributed_solution, > system_rhs, preconditioner); * > > * constraints.distribute(completely_distributed_solution);* > > * locally_relevant_solution = completely_distributed_solution;* > > * }* > > > [0]PETSC ERROR: --------------------- Error Message > -------------------------------------------------------------- > > [0]PETSC ERROR: See > https://www.mcs.anl.gov/petsc/documentation/linearsolvertable.html for > possible LU and Cholesky solvers > > [0]PETSC ERROR: Could not locate a solver package for factorization type > ILU and matrix type mpiaij. > > [0]PETSC ERROR: See https://www.mcs.anl.gov/petsc/documentation/faq.html > for trouble shooting. > > [0]PETSC ERROR: Petsc Release Version 3.13.1, May 02, 2020 > > [0]PETSC ERROR: ./waveLaplaceSolver on a named gbarlogin1 by hsllo Fri > Mar 11 11:05:23 2022 > > [0]PETSC ERROR: Configure options > --prefix=/zhome/32/9/115503/dealii-candi/petsc-3.13.1 --with-debugging=0 > --with-shared-libraries=1 --with-mpi=1 --with-x=0 --with-64-bit-indices=0 > --download-hypre=1 CC=mpicc CXX=mpicxx FC=mpif90 > --with-blaslapack-dir=/appl/OpenBLAS/0.3.17/XeonE5-2660v3/gcc-11.2.0/lib > --with-parmetis-dir=/zhome/32/9/115503/dealii-candi/parmetis-4.0.3 > --with-metis-dir=/zhome/32/9/115503/dealii-candi/parmetis-4.0.3 > --download-scalapack=1 --download-mumps=1 > > [0]PETSC ERROR: #1 MatGetFactor() line 4492 in > /zhome/32/9/115503/dealii-candi/tmp/build/petsc-lite-3.13.1/src/mat/interface/matrix.c > > [0]PETSC ERROR: #2 PCSetUp_ILU() line 133 in > /zhome/32/9/115503/dealii-candi/tmp/build/petsc-lite-3.13.1/src/ksp/pc/impls/factor/ilu/ilu.c > > [0]PETSC ERROR: #3 PCSetUp() line 894 in > /zhome/32/9/115503/dealii-candi/tmp/build/petsc-lite-3.13.1/src/ksp/pc/interface/precon.c > > ---------------------------------------------------- > > Exception on processing: > > -------------------------------------------------------- > > An error occurred in line <431> of file > </zhome/32/9/115503/dealii-candi/tmp/unpack/deal.II-v9.3.1/source/lac/petsc_precondition.cc> > in function > > void dealii::PETScWrappers::PreconditionILU::initialize(const > dealii::PETScWrappers::MatrixBase&, const > dealii::PETScWrappers::PreconditionILU::AdditionalData&) > > The violated condition was: > > ierr == 0 > > Additional information: > > deal.II encountered an error while calling a PETSc function. > > The description of the error provided by PETSc is "See > > https://www.mcs.anl.gov/petsc/documentation/linearsolvertable.html for > > possible LU and Cholesky solvers". > > The numerical value of the original error code is 92. > > > > > > Could you please help me to understand what is happening? > > Thank you again for your help > Regards, > H > El viernes, 11 de marzo de 2022 a las 10:47:37 UTC+1, Hermes Sampedro > escribió: > >> Dear Bruno and Wolfgang, >> >> thank you very much for your comments and help, it is very helpful. >> Actually, I think that is what I am experiencing. When running with my >> actual direct solver a system with 15 elements per direction (4th >> polynomial order with 0.5million dof), the solver takes 50 seconds. >> However, increasing to 30 elements per direction (3.5 million dof) the >> solver takes 1.5 hours. I think this shows how it does not scale well in >> terms of time as you mentioned. I will definitely try with the iterative >> solver. >> >> Thannk you again >> Regards, >> H. >> El jueves, 10 de marzo de 2022 a las 17:17:47 UTC+1, Wolfgang Bangerth >> escribió: >> >>> On 3/10/22 07:00, Hermes Sampedro wrote: >>> > I am experiencing long computational times with the solver function. >>> I am >>> > trying to use DoFRenumbering::Cuthill_McKee(dof_handler), >>> > DoFRenumbering::boost::Cuthill_McKee(dof_handler,false,false) >>> > but I get even higher computational times. Am I doing something wrong? >>> >>> Renumbering makes an enormous difference for sparse direct solvers, and >>> as a >>> consequence all such solvers I know of do it internally (though they use >>> variations of the "minimum degree" renumbering, rather than >>> Cuthill-McKee). As >>> a consequence, renumbering yourself likely makes no difference. >>> >>> But, as you discover and as Bruno already pointed out, even with optimal >>> ordering, direct solvers do not scale well both in terms of overall time >>> and >>> in parallelism. You may want to take a look at the several video >>> lectures on >>> solvers and preconditioners to see what you can do about your case. >>> >>> 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 a topic in the > Google Groups "deal.II User Group" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/dealii/KQGIxkJZL6w/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/dealii/7f6384f4-ebae-4843-83e0-a17abb915e62n%40googlegroups.com > <https://groups.google.com/d/msgid/dealii/7f6384f4-ebae-4843-83e0-a17abb915e62n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- 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. 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