<div dir="ltr">Dear Petsc --<div><br></div><div>I am confused on whether -pc_type mg is supported for SNESVI solvers. The error messages sure aren't helping.</div><div><br></div><div>I am using petsc-maint.</div><div><br></div><div>First I looked at couple of simplest examples in src/snes/examples/tutorials, namely ex9 and ex54. I got mixed results (below), namely crashes with 'nonconforming object sizes' or 'zero pivot' errors in 3 of 4 cases. But I am not sure from the very limited docs what is supposed to work.</div><div><br></div><div>The documented ex54 run itself (see line 12 of ex54.c) just hangs/stagnates for me:</div><div><br></div><div><div>$ ./ex54 -pc_type mg -pc_mg_galerkin -T .01 -da_grid_x 65 -da_grid_y 65 -pc_mg_levels 4 -ksp_type fgmres -snes_atol 1.e-14 -mat_no_inode -snes_vi_monitor -snes_monitor</div><div> 0 SNES Function norm 6.177810506000e-03 </div><div> 0 SNES VI Function norm 6.177810506000e-03 Active lower constraints 0/0 upper constraints 0/0 Percent of total 0 Percent of bounded 0</div><div> 0 SNES Function norm 6.177810506000e-03 </div><div> 0 SNES VI Function norm 6.177810506000e-03 Active lower constraints 0/0 upper constraints 0/0 Percent of total 0 Percent of bounded 0</div><div> 0 SNES Function norm 6.177810506000e-03 </div><div> 0 SNES VI Function norm 6.177810506000e-03 Active lower constraints 0/0 upper constraints 0/0 Percent of total 0 Percent of bounded 0</div><div> 0 SNES Function norm 6.177810506000e-03 </div><div> 0 SNES VI Function norm 6.177810506000e-03 Active lower constraints 0/0 upper constraints 0/0 Percent of total 0 Percent of bounded 0</div><div> 0 SNES Function norm 6.177810506000e-03 </div><div> 0 SNES VI Function norm 6.177810506000e-03 Active lower constraints 0/0 upper constraints 0/0 Percent of total 0 Percent of bounded 0</div></div><div>...</div><div><br></div><div>The wordy documented run of ex55.c stagnates and then seg faults for me (see attachment):</div><div><br></div><div>~/petsc-maint/src/snes/examples/tutorials[maint*]$ ./ex55 -ksp_type fgmres -pc_type mg -mg_levels_ksp_type fgmres -mg_levels_pc_type fieldsplit -mg_levels_pc_fieldsplit_detect_saddle_point -mg_levels_pc_fieldsplit_type schur -mg_levels_pc_fieldsplit_factorization_type full -mg_levels_pc_fieldsplit_schur_precondition user -mg_levels_fieldsplit_1_ksp_type gmres -mg_levels_fieldsplit_1_pc_type none -mg_levels_fieldsplit_0_ksp_type preonly -mg_levels_fieldsplit_0_pc_type sor -mg_levels_fieldsplit_0_pc_sor_forward -snes_vi_monitor -ksp_monitor_true_residual -pc_mg_levels 5 -pc_mg_galerkin -mg_levels_ksp_monitor -mg_levels_fieldsplit_ksp_monitor -mg_levels_ksp_max_it 2 -mg_levels_fieldsplit_ksp_max_it 5 -snes_atol 1.e-11 -mg_coarse_ksp_type preonly -mg_coarse_pc_type svd -da_grid_x 65 -da_grid_y 65 -ksp_rtol 1.e-8 &> out.ex55err<br></div><div><br></div><div>These examples all seem to perform o.k. with default (and non-multigrid) options.</div><div><br></div><div>Thanks for help!</div><div><br></div><div>Ed<br><div><br></div><div><br></div><div>errors from simple ex9, ex54 runs below:</div><div><br></div><div><div>~/petsc-maint/src/snes/examples/tutorials[maint]$ ./ex9 -da_refine 2 -snes_type vinewtonrsls -pc_type mg</div><div>setup done: square side length = 4.000</div><div> grid Mx,My = 41,41</div><div> spacing dx,dy = 0.100,0.100</div><div>[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------</div><div>[0]PETSC ERROR: Nonconforming object sizes</div><div>[0]PETSC ERROR: Mat mat,Vec x: global dim 1388 1681</div><div>[0]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html">http://www.mcs.anl.gov/petsc/documentation/faq.html</a> for trouble shooting.</div><div>[0]PETSC ERROR: Petsc Release Version 3.5.3, unknown </div><div>[0]PETSC ERROR: ./ex9 on a linux-c-opt named bueler-leopard by ed Fri Feb 27 21:02:20 2015</div><div>[0]PETSC ERROR: Configure options --with-cc=gcc --with-cxx=g++ --with-fc=gfortran --download-fblaslapack --download-mpich --with-debugging=0</div><div>[0]PETSC ERROR: #1 MatMultTranspose() line 2232 in /home/ed/petsc-maint/src/mat/interface/matrix.c</div><div>[0]PETSC ERROR: #2 MatRestrict() line 7529 in /home/ed/petsc-maint/src/mat/interface/matrix.c</div><div>[0]PETSC ERROR: #3 DMRestrictHook_SNESVecSol() line 480 in /home/ed/petsc-maint/src/snes/interface/snes.c</div><div>[0]PETSC ERROR: #4 DMRestrict() line 2022 in /home/ed/petsc-maint/src/dm/interface/dm.c</div><div>[0]PETSC ERROR: #5 PCSetUp_MG() line 699 in /home/ed/petsc-maint/src/ksp/pc/impls/mg/mg.c</div><div>[0]PETSC ERROR: #6 PCSetUp() line 902 in /home/ed/petsc-maint/src/ksp/pc/interface/precon.c</div><div>[0]PETSC ERROR: #7 KSPSetUp() line 306 in /home/ed/petsc-maint/src/ksp/ksp/interface/itfunc.c</div><div>[0]PETSC ERROR: #8 SNESSolve_VINEWTONRSLS() line 506 in /home/ed/petsc-maint/src/snes/impls/vi/rs/virs.c</div><div>[0]PETSC ERROR: #9 SNESSolve() line 3743 in /home/ed/petsc-maint/src/snes/interface/snes.c</div><div>[0]PETSC ERROR: #10 main() line 122 in /home/ed/petsc-maint/src/snes/examples/tutorials/ex9.c</div><div>[0]PETSC ERROR: ----------------End of Error Message -------send entire error message to petsc-maint@mcs.anl.gov----------</div><div>application called MPI_Abort(MPI_COMM_WORLD, 60) - process 0</div><div>[unset]: aborting job:</div><div>application called MPI_Abort(MPI_COMM_WORLD, 60) - process 0</div><div><br></div><div><br></div><div>~/petsc-maint/src/snes/examples/tutorials[maint]$ ./ex9 -da_refine 2 -snes_type vinewtonssls -pc_type mg</div><div>setup done: square side length = 4.000</div><div> grid Mx,My = 41,41</div><div> spacing dx,dy = 0.100,0.100</div><div>number of Newton iterations = 8; result = CONVERGED_FNORM_RELATIVE</div><div>errors: av |u-uexact| = 2.909e-04</div><div> |u-uexact|_inf = 1.896e-03</div><div><br></div><div><br></div><div>~/petsc-maint/src/snes/examples/tutorials[maint]$ ./ex54 -snes_monitor -da_refine 2 -snes_type vinewtonssls -pc_type mg</div><div> 0 SNES Function norm 3.156635589354e-02 </div><div>[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------</div><div>[0]PETSC ERROR: Zero pivot in LU factorization: <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#ZeroPivot">http://www.mcs.anl.gov/petsc/documentation/faq.html#ZeroPivot</a></div><div>[0]PETSC ERROR: Zero pivot, row 0</div><div>[0]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html">http://www.mcs.anl.gov/petsc/documentation/faq.html</a> for trouble shooting.</div><div>[0]PETSC ERROR: Petsc Release Version 3.5.3, unknown </div><div>[0]PETSC ERROR: ./ex54 on a linux-c-opt named bueler-leopard by ed Fri Feb 27 21:02:43 2015</div><div>[0]PETSC ERROR: Configure options --with-cc=gcc --with-cxx=g++ --with-fc=gfortran --download-fblaslapack --download-mpich --with-debugging=0</div><div>[0]PETSC ERROR: #1 PetscKernel_A_gets_inverse_A_2() line 50 in /home/ed/petsc-maint/src/mat/impls/baij/seq/dgefa2.c</div><div>[0]PETSC ERROR: #2 MatSOR_SeqAIJ_Inode() line 2806 in /home/ed/petsc-maint/src/mat/impls/aij/seq/inode.c</div><div>[0]PETSC ERROR: #3 MatSOR() line 3643 in /home/ed/petsc-maint/src/mat/interface/matrix.c</div><div>[0]PETSC ERROR: #4 PCApply_SOR() line 35 in /home/ed/petsc-maint/src/ksp/pc/impls/sor/sor.c</div><div>[0]PETSC ERROR: #5 PCApply() line 440 in /home/ed/petsc-maint/src/ksp/pc/interface/precon.c</div><div>[0]PETSC ERROR: #6 KSP_PCApply() line 230 in /home/ed/petsc-maint/include/petsc-private/kspimpl.h</div><div>[0]PETSC ERROR: #7 KSPInitialResidual() line 56 in /home/ed/petsc-maint/src/ksp/ksp/interface/itres.c</div><div>[0]PETSC ERROR: #8 KSPSolve_GMRES() line 234 in /home/ed/petsc-maint/src/ksp/ksp/impls/gmres/gmres.c</div><div>[0]PETSC ERROR: #9 KSPSolve() line 460 in /home/ed/petsc-maint/src/ksp/ksp/interface/itfunc.c</div><div>[0]PETSC ERROR: #10 KSPSolve_Chebyshev() line 368 in /home/ed/petsc-maint/src/ksp/ksp/impls/cheby/cheby.c</div><div>[0]PETSC ERROR: #11 KSPSolve() line 460 in /home/ed/petsc-maint/src/ksp/ksp/interface/itfunc.c</div><div>[0]PETSC ERROR: #12 PCMGMCycle_Private() line 19 in /home/ed/petsc-maint/src/ksp/pc/impls/mg/mg.c</div><div>[0]PETSC ERROR: #13 PCMGMCycle_Private() line 48 in /home/ed/petsc-maint/src/ksp/pc/impls/mg/mg.c</div><div>[0]PETSC ERROR: #14 PCApply_MG() line 337 in /home/ed/petsc-maint/src/ksp/pc/impls/mg/mg.c</div><div>[0]PETSC ERROR: #15 PCApply() line 440 in /home/ed/petsc-maint/src/ksp/pc/interface/precon.c</div><div>[0]PETSC ERROR: #16 KSP_PCApply() line 230 in /home/ed/petsc-maint/include/petsc-private/kspimpl.h</div><div>[0]PETSC ERROR: #17 KSPInitialResidual() line 63 in /home/ed/petsc-maint/src/ksp/ksp/interface/itres.c</div><div>[0]PETSC ERROR: #18 KSPSolve_GMRES() line 234 in /home/ed/petsc-maint/src/ksp/ksp/impls/gmres/gmres.c</div><div>[0]PETSC ERROR: #19 KSPSolve() line 460 in /home/ed/petsc-maint/src/ksp/ksp/interface/itfunc.c</div><div>[0]PETSC ERROR: #20 SNESSolve_VINEWTONSSLS() line 317 in /home/ed/petsc-maint/src/snes/impls/vi/ss/viss.c</div><div>[0]PETSC ERROR: #21 SNESSolve() line 3743 in /home/ed/petsc-maint/src/snes/interface/snes.c</div><div>[0]PETSC ERROR: #22 main() line 98 in /home/ed/petsc-maint/src/snes/examples/tutorials/ex54.c</div><div>[0]PETSC ERROR: ----------------End of Error Message -------send entire error message to petsc-maint@mcs.anl.gov----------</div><div>application called MPI_Abort(MPI_COMM_WORLD, 71) - process 0</div><div>[unset]: aborting job:</div><div>application called MPI_Abort(MPI_COMM_WORLD, 71) - process 0</div><div><br></div><div><br></div><div>~/petsc-maint/src/snes/examples/tutorials[maint]$ ./ex54 -snes_monitor -da_refine 2 -snes_type vinewtonrsls -pc_type mg</div><div> 0 SNES Function norm 3.160548858489e-02 </div><div>[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------</div><div>[0]PETSC ERROR: Zero pivot in LU factorization: <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#ZeroPivot">http://www.mcs.anl.gov/petsc/documentation/faq.html#ZeroPivot</a></div><div>[0]PETSC ERROR: Zero pivot, row 0</div><div>[0]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html">http://www.mcs.anl.gov/petsc/documentation/faq.html</a> for trouble shooting.</div><div>[0]PETSC ERROR: Petsc Release Version 3.5.3, unknown </div><div>[0]PETSC ERROR: ./ex54 on a linux-c-opt named bueler-leopard by ed Fri Feb 27 21:02:48 2015</div><div>[0]PETSC ERROR: Configure options --with-cc=gcc --with-cxx=g++ --with-fc=gfortran --download-fblaslapack --download-mpich --with-debugging=0</div><div>[0]PETSC ERROR: #1 PetscKernel_A_gets_inverse_A_2() line 50 in /home/ed/petsc-maint/src/mat/impls/baij/seq/dgefa2.c</div><div>[0]PETSC ERROR: #2 MatSOR_SeqAIJ_Inode() line 2806 in /home/ed/petsc-maint/src/mat/impls/aij/seq/inode.c</div><div>[0]PETSC ERROR: #3 MatSOR() line 3643 in /home/ed/petsc-maint/src/mat/interface/matrix.c</div><div>[0]PETSC ERROR: #4 PCApply_SOR() line 35 in /home/ed/petsc-maint/src/ksp/pc/impls/sor/sor.c</div><div>[0]PETSC ERROR: #5 PCApply() line 440 in /home/ed/petsc-maint/src/ksp/pc/interface/precon.c</div><div>[0]PETSC ERROR: #6 KSP_PCApply() line 230 in /home/ed/petsc-maint/include/petsc-private/kspimpl.h</div><div>[0]PETSC ERROR: #7 KSPInitialResidual() line 56 in /home/ed/petsc-maint/src/ksp/ksp/interface/itres.c</div><div>[0]PETSC ERROR: #8 KSPSolve_GMRES() line 234 in /home/ed/petsc-maint/src/ksp/ksp/impls/gmres/gmres.c</div><div>[0]PETSC ERROR: #9 KSPSolve() line 460 in /home/ed/petsc-maint/src/ksp/ksp/interface/itfunc.c</div><div>[0]PETSC ERROR: #10 KSPSolve_Chebyshev() line 368 in /home/ed/petsc-maint/src/ksp/ksp/impls/cheby/cheby.c</div><div>[0]PETSC ERROR: #11 KSPSolve() line 460 in /home/ed/petsc-maint/src/ksp/ksp/interface/itfunc.c</div><div>[0]PETSC ERROR: #12 PCMGMCycle_Private() line 19 in /home/ed/petsc-maint/src/ksp/pc/impls/mg/mg.c</div><div>[0]PETSC ERROR: #13 PCMGMCycle_Private() line 48 in /home/ed/petsc-maint/src/ksp/pc/impls/mg/mg.c</div><div>[0]PETSC ERROR: #14 PCApply_MG() line 337 in /home/ed/petsc-maint/src/ksp/pc/impls/mg/mg.c</div><div>[0]PETSC ERROR: #15 PCApply() line 440 in /home/ed/petsc-maint/src/ksp/pc/interface/precon.c</div><div>[0]PETSC ERROR: #16 KSP_PCApply() line 230 in /home/ed/petsc-maint/include/petsc-private/kspimpl.h</div><div>[0]PETSC ERROR: #17 KSPInitialResidual() line 63 in /home/ed/petsc-maint/src/ksp/ksp/interface/itres.c</div><div>[0]PETSC ERROR: #18 KSPSolve_GMRES() line 234 in /home/ed/petsc-maint/src/ksp/ksp/impls/gmres/gmres.c</div><div>[0]PETSC ERROR: #19 KSPSolve() line 460 in /home/ed/petsc-maint/src/ksp/ksp/interface/itfunc.c</div><div>[0]PETSC ERROR: #20 SNESSolve_VINEWTONRSLS() line 536 in /home/ed/petsc-maint/src/snes/impls/vi/rs/virs.c</div><div>[0]PETSC ERROR: #21 SNESSolve() line 3743 in /home/ed/petsc-maint/src/snes/interface/snes.c</div><div>[0]PETSC ERROR: #22 main() line 98 in /home/ed/petsc-maint/src/snes/examples/tutorials/ex54.c</div><div>[0]PETSC ERROR: ----------------End of Error Message -------send entire error message to petsc-maint@mcs.anl.gov----------</div><div>application called MPI_Abort(MPI_COMM_WORLD, 71) - process 0</div><div>[unset]: aborting job:</div><div>application called MPI_Abort(MPI_COMM_WORLD, 71) - process 0</div><div><br></div><div><br></div>-- <br><div class="gmail_signature">Ed Bueler<br>Dept of Math and Stat and Geophysical Institute<br>University of Alaska Fairbanks<br>Fairbanks, AK 99775-6660<br>301C Chapman and 410D Elvey<br>907 474-7693 and 907 474-7199 (fax 907 474-5394)</div>
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