Hi Matt, Thanks for the pointer. Yan
On Mon, Sep 21, 2009 at 2:40 PM, Matthew Knepley <knepley at gmail.com> wrote: > You can use KSPBuildResidual(). > > Matt > > > On Mon, Sep 21, 2009 at 12:44 PM, Ryan Yan <vyan2000 at gmail.com> wrote: > >> Hi All, >> The following question is only for test and comparison reason. >> >> Is there a command line option to set up using 1-Norm(sum of absolute >> value of residuals) as convergence monitor and test. >> >> Alternatively, if I can get the residual "r" out at the end of each >> iteration, then it is going to be much simpler, since I can just call >> VecNorm(r, NORM_1, &r_ell1) and pass the r_ell1 into the convergence monitor >> and test. Can anyone inform me if PETSc has an interface for the resuidual >> r? >> >> Or one has to call the convergence test: >> MyKSPConverged(ksp,n,rnorm,flag,dummy); >> and following the steps: >> 1. fetch the exact solution: >> >> KSPBuildSolution(ksp,PETSC_NULL_OBJECT,x,ierr) >> >> 2. calculate the residual: >> >> pass the Right Hand side and the Matrix in to calculate the 1-Norm. But >> this step is *not* obvious, since the matrix and rhs is already distributed >> over each processes. >> >> 3. set up the convergence test based on the 1_Norm residual. >> >> >> Thank you very much, >> >> >> Yan >> > > > > -- > 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 > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20090921/8049dfb5/attachment.htm>
