Hi, I have some questions regarding the use of hypre/boomeramg:
1. Is there anything I need to change in the assembly of matrix etc besides adding -pc_type hypre -pc_hypre_type boomeramg ? 2. Can it work in a sequential code? 3. I have 2 eqns to solve - momentum and poisson. if I used the options, will both equations be solved using hypre? Can I select which solver to solve with which equation? Thank you. On 2/12/07, Barry Smith <bsmith at mcs.anl.gov> wrote: > > > hypre/boomeramg may be the way to go, especially for the Poisson > problem. -pc_type hypre -pc_hypre_type boomeramg (-help for lots of > tuning options.). > > Barry > > > On Sun, 11 Feb 2007, Ben Tay wrote: > > > Well, > > > > I am simulating unsteady flow past a moving airfoil at Re~10^4. I'm > using > > fractional step FVM, which means that I need to solve a momentum and > poisson > > equation. > > > > To reach a periodic state takes quite a few hours and so I'm trying to > find > > ways to speed up the process. I thought parallelizing the code would > help > > but it seems like it's not the case. > > > > I'm now trying out different types of solver/preconditioner available on > > PETSc to assess their performance. Is there other external solvers, > which > > PETSc interfaces, which are recommended? I'm thinking of using multigrid > to > > solve the poisson eqn... wonder if hypre/BoomerAMG etc would help... > > > > > > On 2/11/07, Lisandro Dalcin <dalcinl at gmail.com> wrote: > > > > > > On 2/10/07, Ben Tay <zonexo at gmail.com> wrote: > > > > In other words, for my CFD code, it is not possible to parallelize > it > > > > effectively because the problem is too small? > > > > > > > > Is these true for all parallel solver, or just PETSc? I was hoping > to > > > reduce > > > > the runtime since mine is an unsteady problem which requires many > steps > > > to > > > > reach a periodic state and it takes many hours to reach it. > > > > > > Can you describe your specific application and how are you solving it? > > > As Barry said, your need-for-speed is not likely to be solved by > > > running in parallel. > > > > > > > > > -- > > > Lisandro Dalc?n > > > --------------- > > > Centro Internacional de M?todos Computacionales en Ingenier?a (CIMEC) > > > Instituto de Desarrollo Tecnol?gico para la Industria Qu?mica (INTEC) > > > Consejo Nacional de Investigaciones Cient?ficas y T?cnicas (CONICET) > > > PTLC - G?emes 3450, (3000) Santa Fe, Argentina > > > Tel/Fax: +54-(0)342-451.1594 > > > > > > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20070212/4c6b63e4/attachment.htm>
