On Fri, Mar 16, 2018 at 12:54 PM, TAY wee-beng <zon...@gmail.com> wrote:
> > On 15/3/2018 6:21 PM, Matthew Knepley wrote: > > On Thu, Mar 15, 2018 at 3:51 PM, TAY wee-beng <zon...@gmail.com> wrote: > >> Hi, >> >> I'm running a CFD code which solves the momentum and Poisson eqns. >> >> Due to poor scaling with HYPRE at higher cpu no., I decided to try using >> PETSc with boomeramg and gamg. >> >> I tested for some small cases and it work well. However, for the large >> problem which has poor scaling, it gives an error when I change my Poisson >> solver from pure HYPRE to PETSc with boomeramg and gamg. >> >> The error is : >> >> Caught signal number 11 SEGV: Segmentation Violation, probably memory >> access out of range >> >> I tried using: >> >> -poisson_ksp_type richardson -poisson_pc_type hypre >> -poisson_pc_type_hypre boomeramg >> >> -poisson_ksp_type gmres -poisson_pc_type hypre -poisson_pc_type_hypre >> boomeramg >> >> -poisson_pc_type gamg -poisson_pc_gamg_agg_nsmooths 1 >> >> but they all gave similar error. >> >> So why is this so? How should I troubleshoot? I am now running a debug >> ver of PETSc to check the error msg. > > > 1) For anything like this, we would like to see a stack trace from the > debugger or valgrind output. > > 2) We do have several Poisson examples. Does it fail for you on those? > > Hi, > > Can you recommend me some suitable egs? Esp in Fortran? > Here is 2D Poisson https://bitbucket.org/petsc/petsc/src/4b6141395f14f0c7d1415a2ff0158eec75a27d63/src/snes/examples/tutorials/ex5f.F90?at=master&fileviewer=file-view-default > > 3) You can also try ML, which is the same type of MG as GAMG. > (--download-ml). > > My cluster can't connect to the internet. Where can I 1st download it? > > Similarly, how can I find out the location of the ext software by myself? > The locations are all in the configure Python modules: https://bitbucket.org/petsc/petsc/src/4b6141395f14f0c7d1415a2ff0158eec75a27d63/config/BuildSystem/config/packages/ml.py?at=master&fileviewer=file-view-default Thanks, Matt > Thanks, > > Matt > > >> >> -- >> Thank you very much. >> >> Yours sincerely, >> >> ================================================ >> TAY Wee-Beng (Zheng Weiming) ιδΌζ >> Personal research webpage: http://tayweebeng.wixsite.com/website >> Youtube research showcase: https://www.youtube.com/channe >> l/UC72ZHtvQNMpNs2uRTSToiLA >> linkedin: www.linkedin.com/in/tay-weebeng >> ================================================ >> >> > > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which their > experiments lead. > -- Norbert Wiener > > https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/%7Emk51/> > > > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>