I'm getting an FPE in LAPACKgesvd of KSPComputeExtremeSingularValues_GMRES. I'm not sure where this routine is required during the algorithm as I'm using BiCG + richardson/SOR on all multigrid levels. Also, even though I've set mg_coarse_ksp_type richardson, KSPView is showing that preonly is used on the coarsest level. Am I misunderstanding something about the options I'm using?
-pres_ksp_type preonly -pres_pc_type redistribute -pres_redistribute_ksp_type bcgsl -pres_redistribute_pc_type gamg -pres_redistribute_pc_gamg_threshold 0.01 -pres_redistribute_mg_levels_ksp_type richardson -pres_redistribute_mg_levels_pc_type sor -pres_redistribute_mg_coarse_ksp_type richardson -pres_redistribute_mg_coarse_pc_type sor -pres_redistribute_mg_coarse_pc_sor_its 4 -pres_redistribute_pc_gamg_agg_nsmooths 1 -pres_redistribute_pc_gamg_sym_graph true -pres_redistribute_gamg_type agg -pres_ksp_view [8]PETSC ERROR: ------------------------------------------------------------------------ [8]PETSC ERROR: Caught signal number 8 FPE: Floating Point Exception,probably divide by zero [8]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger [8]PETSC ERROR: or see http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[8]PETSC ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to find memory corruption errors [40]PETSC ERROR: ------------------------------------------------------------------------ [40]PETSC ERROR: Caught signal number 8 FPE: Floating Point Exception,probably divide by zero [40]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger [40]PETSC ERROR: or see http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[40]PETSC ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to find memory corruption errors [40]PETSC ERROR: likely location of problem given in stack below [40]PETSC ERROR: --------------------- Stack Frames ------------------------------------ [40]PETSC ERROR: Note: The EXACT line numbers in the stack are not available, [40]PETSC ERROR: INSTEAD the line number of the start of the function [40]PETSC ERROR: is given. [40]PETSC ERROR: [40] LAPACKgesvd line 42 /Users/jmousel/SOFT/petsc/src/ksp/ksp/impls/gmres/gmreig.c [40]PETSC ERROR: [40] KSPComputeExtremeSingularValues_GMRES line 24 /Users/jmousel/SOFT/petsc/src/ksp/ksp/impls/gmres/gmreig.c [40]PETSC ERROR: [40] KSPComputeExtremeSingularValues line 51 /Users/jmousel/SOFT/petsc/src/ksp/ksp/interface/itfunc.c KSP Object:proj_ksp(pres_) 96 MPI processes type: preonly maximum iterations=1000, initial guess is zero tolerances: relative=1e-50, absolute=0.01, divergence=10000 left preconditioning using NONE norm type for convergence test PC Object:(pres_) 96 MPI processes type: redistribute Number rows eliminated 7115519 Percentage rows eliminated 44.1051 Redistribute preconditioner: KSP Object: (pres_redistribute_) 96 MPI processes type: bcgsl BCGSL: Ell = 2 BCGSL: Delta = 0 maximum iterations=1000, initial guess is zero tolerances: relative=1e-50, absolute=0.01, divergence=10000 left preconditioning has attached null space using PRECONDITIONED norm type for convergence test PC Object: (pres_redistribute_) 96 MPI processes type: gamg MG: type is MULTIPLICATIVE, levels=4 cycles=v Cycles per PCApply=1 Using Galerkin computed coarse grid matrices Coarse grid solver -- level ------------------------------- KSP Object: (pres_redistribute_mg_coarse_) 96 MPI processes type: preonly maximum iterations=1, initial guess is zero tolerances: relative=1e-05, absolute=1e-50, divergence=10000 left preconditioning using NONE norm type for convergence test PC Object: (pres_redistribute_mg_coarse_) 96 MPI processes type: sor SOR: type = local_symmetric, iterations = 4, local iterations = 1, omega = 1 linear system matrix = precond matrix: Mat Object: 96 MPI processes type: mpiaij rows=465, cols=465 total: nonzeros=84523, allocated nonzeros=84523 total number of mallocs used during MatSetValues calls =0 not using I-node (on process 0) routines Down solver (pre-smoother) on level 1 ------------------------------- KSP Object: (pres_redistribute_mg_levels_1_) 96 MPI processes type: richardson Richardson: damping factor=1 maximum iterations=2 tolerances: relative=1e-05, absolute=1e-50, divergence=10000 left preconditioning using nonzero initial guess using NONE norm type for convergence test PC Object: (pres_redistribute_mg_levels_1_) 96 MPI processes type: sor SOR: type = local_symmetric, iterations = 1, local iterations = 1, omega = 1 linear system matrix = precond matrix: Mat Object: 96 MPI processes type: mpiaij rows=13199, cols=13199 total: nonzeros=2.09436e+06, allocated nonzeros=2.09436e+06 total number of mallocs used during MatSetValues calls =0 not using I-node (on process 0) routines Up solver (post-smoother) same as down solver (pre-smoother) Down solver (pre-smoother) on level 2 ------------------------------- KSP Object: (pres_redistribute_mg_levels_2_) 96 MPI processes type: richardson Richardson: damping factor=1 maximum iterations=2 tolerances: relative=1e-05, absolute=1e-50, divergence=10000 left preconditioning using nonzero initial guess using NONE norm type for convergence test PC Object: (pres_redistribute_mg_levels_2_) 96 MPI processes type: sor SOR: type = local_symmetric, iterations = 1, local iterations = 1, omega = 1 linear system matrix = precond matrix: Mat Object: 96 MPI processes type: mpiaij rows=568202, cols=568202 total: nonzeros=2.33509e+07, allocated nonzeros=2.33509e+07 total number of mallocs used during MatSetValues calls =0 not using I-node (on process 0) routines Up solver (post-smoother) same as down solver (pre-smoother) Down solver (pre-smoother) on level 3 ------------------------------- KSP Object: (pres_redistribute_mg_levels_3_) 96 MPI processes type: richardson Richardson: damping factor=1 maximum iterations=2 tolerances: relative=1e-05, absolute=1e-50, divergence=10000 left preconditioning using nonzero initial guess using NONE norm type for convergence test PC Object: (pres_redistribute_mg_levels_3_) 96 MPI processes type: sor SOR: type = local_symmetric, iterations = 1, local iterations = 1, omega = 1 linear system matrix = precond matrix: Mat Object: 96 MPI processes type: mpiaij rows=9017583, cols=9017583 total: nonzeros=1.01192e+08, allocated nonzeros=1.01192e+08 total number of mallocs used during MatSetValues calls =0 not using I-node (on process 0) routines Up solver (post-smoother) same as down solver (pre-smoother) linear system matrix = precond matrix: Mat Object: 96 MPI processes type: mpiaij rows=9017583, cols=9017583 total: nonzeros=1.01192e+08, allocated nonzeros=1.01192e+08 total number of mallocs used during MatSetValues calls =0 not using I-node (on process 0) routines linear system matrix = precond matrix: Mat Object: proj_A 96 MPI processes type: mpiaij rows=16133102, cols=16133102 total: nonzeros=1.09807e+08, allocated nonzeros=1.57582e+08 total number of mallocs used during MatSetValues calls =0 not using I-node (on process 0) routines Residual norms for vel_ solve.
