On Sat, Oct 21, 2017 at 5:21 PM, Hao Zhang <[email protected]> wrote:
> ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY); > ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY); > > ierr = VecAssemblyBegin(x); > ierr = VecAssemblyEnd(x); > This is probably unnecessary > > ierr = VecAssemblyBegin(b); > ierr = VecAssemblyEnd(b); > This is probably unnecessary > > > ierr = MatNullSpaceCreate(PETSC_COMM_WORLD,PETSC_TRUE,0,PETSC_NULL, > &nullsp); > ierr = MatSetNullSpace(A,nullsp); // Petsc-3.8 > Is your rhs consistent with this nullspace? > // KSPSetOperators(ksp,A,A,DIFFERENT_NONZERO_PATTERN); > KSPSetOperators(ksp,A,A); > > KSPSetType(ksp,KSPBCGS); > > KSPSetComputeSingularValues(ksp, PETSC_TRUE); > #if defined(__HYPRE__) > KSPGetPC(ksp, &pc); > PCSetType(pc, PCHYPRE); > PCHYPRESetType(pc,"boomeramg"); > This is terribly unnecessary. You just use -pc_type hypre -pc_hypre_type boomeramg or -pc_type gamg > #else > KSPSetType(ksp,KSPBCGSL); > KSPBCGSLSetEll(ksp,2); > #endif /* defined(__HYPRE__) */ > > KSPSetFromOptions(ksp); > KSPSetUp(ksp); > > ierr = KSPSolve(ksp,b,x); > > > command line > You did not provide any of what I asked for the in the eprevious mail. Matt > On Sat, Oct 21, 2017 at 5:16 PM, Matthew Knepley <[email protected]> > wrote: > >> On Sat, Oct 21, 2017 at 5:04 PM, Hao Zhang <[email protected]> wrote: >> >>> hi, >>> >>> I implemented HYPRE preconditioner for my study due to the fact that >>> without preconditioner, PETSc solver will take thousands of iterations to >>> converge for fine grid simulation. >>> >>> with HYPRE, depending on the parallel partition, it will take HYPRE >>> forever to do anything. observation of output file is that the simulation >>> is hanging with no output. >>> >>> Any idea what happened? will post snippet of code. >>> >> >> 1) For any question about convergence, we need to see the output of >> >> -ksp_view_pre -ksp_view -ksp_monitor_true_residual -ksp_converged_reason >> >> 2) Hypre has many preconditioners, which one are you talking about >> >> 3) PETSc has some preconditioners in common with Hypre, like AMG >> >> Thanks, >> >> Matt >> >> >>> -- >>> Hao Zhang >>> Dept. of Applid Mathematics and Statistics, >>> Stony Brook University, >>> Stony Brook, New York, 11790 >>> >> >> >> >> -- >> 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/> >> > > > > -- > Hao Zhang > Dept. of Applid Mathematics and Statistics, > Stony Brook University, > Stony Brook, New York, 11790 > -- 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/>
