Telescope isn't my thing, but you're correct that the data (SNES or otherwise) required by KSPComputeOperators isn't available on the subcommunicator. If you want this feature, I don't know any way to go about it other than to use the hooks so the user can redistribute their problem data to new communicators. I agree it is difficult to implement in general.
Barry Smith <[email protected]> writes: > From the manual page: KSPSetComputeOperators() is not propagated to the > sub KSP. > > Yet there is some code > sred->ignore_kspcomputeoperators = PETSC_FALSE; > if (sred->ignore_kspcomputeoperators) { > ierr = PetscViewerASCIIPrintf(subviewer," Telescope: ignoring > KSPComputeOperators\n");CHKERRQ(ierr); > } > ierr = PetscOptionsBool("-pc_telescope_ignore_kspcomputeoperators","Ignore > method used to compute > A","PCTelescopeSetIgnoreKSPComputeOperators",sred->ignore_kspcomputeoperators,&sred->ignore_kspcomputeoperators,0);CHKERRQ(ierr); > etc > > that seems to indicate that Dave May intended to have support for > KSPComputeOperator ... but didn't complete it. > > In this case it is using KSPComputeOperators_SNES(KSP ksp,Mat A,Mat B,void > *ctx); which needs a couple of things changed to get it to work: > > 1) KSPComputeOperators_SNES() needs to work when the subdm is on a smaller > set of processes so the call to SNESComputeJacobian() has to handle running > on a subset of process (which of course it cannot do normally because the > SNES has its full communicator while the DM only lives on a subset of > processes). > > 2) The DMRestrictHook_SNESVecSol() has to handle switching to a DM on a > smaller set of processes and remapping the "solution" vector to that smaller > set. > > Dave and Jed, > > All and all looks awfully complex and fragile to get this working. What > do you think? > > Barry > > Curse whoever designed PETSc originally and didn't take into account in its > basic design the need to subcom PETSc objects to smaller communicators :-( > > > >> On Feb 13, 2017, at 10:01 AM, Zhang, Hong <[email protected]> wrote: >> >> Hi Barry, >> >> When using telescope, I get an error complaining about missing Jacobian. But >> apparently I have a Jacobian set by TSSetIJacobian(). >> >> [0]PETSC ERROR: --------------------- Error Message >> -------------------------------------------------------------- >> [0]PETSC ERROR: >> [0]PETSC ERROR: Must call SNESSetJacobian(), DMSNESSetJacobian(), >> DMDASNESSetJacobianLocal(), etc >> [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for >> trouble shooting. >> [0]PETSC ERROR: Petsc Development GIT revision: v3.7.4-2764-g0ff3c95 GIT >> Date: 2017-01-10 15:40:21 -0600 >> [0]PETSC ERROR: ./ex5adj_ell on a arch-memalign-mkl-avx512-opt named >> isdp001.cels.anl.gov by hongzh Mon Feb 13 09:56:48 2017 >> [0]PETSC ERROR: Configure options --COPTFLAGS="-g -O3 -xMIC-AVX512" >> --CXXOPTFLAGS="-g -O3 -xMIC-AVX512" --FOPTFLAGS="-g -O3 -xMIC-AVX512" >> --PETSC_ARCH=arch-memalign-mkl-avx512-opt >> --PETSC_DIR=/homes/hongzh/Projects/petsc --download-cmake >> --download-revolve=1 >> --with-blaslapack-dir=/opt/intel/2017-initial/compilers_and_libraries_2017/linux/mkl/lib/intel64 >> --with-cc=mpiicc --with-cxx=mpiicpc --with-debugging=no --with-fc=mpiifort >> --with-memalign=64 --with-mpiexec=mpirun >> [0]PETSC ERROR: #1 SNESComputeJacobian() line 2242 in >> /home/hongzh/Projects/petsc/src/snes/interface/snes.c >> [0]PETSC ERROR: #2 KSPComputeOperators_SNES() line 569 in >> /home/hongzh/Projects/petsc/src/snes/interface/snes.c >> [0]PETSC ERROR: #3 KSPSetUp() line 327 in >> /home/hongzh/Projects/petsc/src/ksp/ksp/interface/itfunc.c >> [0]PETSC ERROR: #4 KSPSolve() line 599 in >> /home/hongzh/Projects/petsc/src/ksp/ksp/interface/itfunc.c >> [0]PETSC ERROR: #5 PCApply_Telescope_dmda() line 952 in >> /home/hongzh/Projects/petsc/src/ksp/pc/impls/telescope/telescope_dmda.c >> [0]PETSC ERROR: #6 PCApply() line 458 in >> /home/hongzh/Projects/petsc/src/ksp/pc/interface/precon.c >> [0]PETSC ERROR: #7 KSP_PCApply() line 251 in >> /homes/hongzh/Projects/petsc/include/petsc/private/kspimpl.h >> [0]PETSC ERROR: #8 KSPSolve_PREONLY() line 22 in >> /home/hongzh/Projects/petsc/src/ksp/ksp/impls/preonly/preonly.c >> [0]PETSC ERROR: #9 KSPSolve() line 656 in >> /home/hongzh/Projects/petsc/src/ksp/ksp/interface/itfunc.c >> [0]PETSC ERROR: #10 PCMGMCycle_Private() line 19 in >> /home/hongzh/Projects/petsc/src/ksp/pc/impls/mg/mg.c >> [0]PETSC ERROR: #11 PCMGMCycle_Private() line 53 in >> /home/hongzh/Projects/petsc/src/ksp/pc/impls/mg/mg.c >> [0]PETSC ERROR: #12 PCMGMCycle_Private() line 53 in >> /home/hongzh/Projects/petsc/src/ksp/pc/impls/mg/mg.c >> [0]PETSC ERROR: #13 PCMGMCycle_Private() line 53 in >> /home/hongzh/Projects/petsc/src/ksp/pc/impls/mg/mg.c >> [0]PETSC ERROR: #14 PCMGMCycle_Private() line 53 in >> /home/hongzh/Projects/petsc/src/ksp/pc/impls/mg/mg.c >> [0]PETSC ERROR: #15 PCApply_MG() line 331 in >> /home/hongzh/Projects/petsc/src/ksp/pc/impls/mg/mg.c >> [0]PETSC ERROR: #16 PCApply() line 458 in >> /home/hongzh/Projects/petsc/src/ksp/pc/interface/precon.c >> [0]PETSC ERROR: #17 KSP_PCApply() line 251 in >> /homes/hongzh/Projects/petsc/include/petsc/private/kspimpl.h >> [0]PETSC ERROR: #18 KSPInitialResidual() line 67 in >> /home/hongzh/Projects/petsc/src/ksp/ksp/interface/itres.c >> [0]PETSC ERROR: #19 KSPSolve_GMRES() line 233 in >> /home/hongzh/Projects/petsc/src/ksp/ksp/impls/gmres/gmres.c >> [0]PETSC ERROR: #20 KSPSolve() line 656 in >> /home/hongzh/Projects/petsc/src/ksp/ksp/interface/itfunc.c >> [0]PETSC ERROR: #21 SNESSolve_NEWTONLS() line 224 in >> /home/hongzh/Projects/petsc/src/snes/impls/ls/ls.c >> [0]PETSC ERROR: #22 SNESSolve() line 3967 in >> /home/hongzh/Projects/petsc/src/snes/interface/snes.c >> [0]PETSC ERROR: #23 TS_SNESSolve() line 171 in >> /home/hongzh/Projects/petsc/src/ts/impls/implicit/theta/theta.c >> [0]PETSC ERROR: #24 TSStep_Theta() line 211 in >> /home/hongzh/Projects/petsc/src/ts/impls/implicit/theta/theta.c >> [0]PETSC ERROR: #25 TSStep() line 3808 in >> /home/hongzh/Projects/petsc/src/ts/interface/ts.c >> [0]PETSC ERROR: #26 TSSolve() line 4053 in >> /home/hongzh/Projects/petsc/src/ts/interface/ts.c >> [0]PETSC ERROR: #27 main() line 171 in >> /homes/hongzh/Projects/petsc/src/ts/examples/tutorials/advection-diffusion-reaction/ex5adj_ell.c >> [0]PETSC ERROR: PETSc Option Table entries: >> [0]PETSC ERROR: -da_refine 4 >> [0]PETSC ERROR: -dm_mat_type aij >> [0]PETSC ERROR: -forwardonly >> [0]PETSC ERROR: -ksp_converged_reason >> [0]PETSC ERROR: -ksp_view >> [0]PETSC ERROR: -mg_coarse_pc_telescope_reduction_factor 2 >> [0]PETSC ERROR: -mg_coarse_pc_type telescope >> [0]PETSC ERROR: -mg_coarse_telescope_pc_type lu >> [0]PETSC ERROR: -mg_levels_pc_type jacobi >> [0]PETSC ERROR: -pc_type mg >> [0]PETSC ERROR: -ts_dt 1 >> [0]PETSC ERROR: -ts_max_steps 1 >> [0]PETSC ERROR: ----------------End of Error Message -------send entire >> error message to [email protected] >> >> Thanks, >> Hong
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