Hello, The fix suggested by Mark resolves the error: #define GAMG_HASH(key) (PetscInt)((((PetscInt64)7)*(PetscInt64)key)%(PetscInt64)a_tab->size)
I’m guessing this is similar to the fix suggested by Barry: #define GAMG_HASH(key) ((((PetscInt64)7)*key)%a_tab->size) FWIW, my problem has around 1.2B d.o.f., so if the key is something like a column or row index, that could explain the error when doing 7*key Thanks, Pierre > On 24 Jun 2018, at 11:28 PM, Smith, Barry F. <[email protected]> wrote: > > > Pierre, > > Can you confirm if my suggested fix resolved the error message or not? If > so, we'll add it to the maint branch. > > Thanks > > Barry > > > https://stackoverflow.com/questions/11720656/modulo-operation-with-negative-numbers > > > >> On Jun 24, 2018, at 4:19 PM, Mark Adams <[email protected]> wrote: >> >> >> >> On Sun, Jun 24, 2018 at 2:09 PM Smith, Barry F. <[email protected]> wrote: >> >> >>> On Jun 24, 2018, at 11:15 AM, Mark Adams <[email protected]> wrote: >>> >>> First, -pc_gamg_threshold 0.8 is crazy. 0.08 is very high. probably best >>> to start with 0. >>> >>> This threshold will delete all of your edges in the coarsening graph, >>> probably, and GAMG will switch to a one level solve (silently although >>> -info will tell you). >>> >>> And yes, this looks like a 64 bit indices problem, we have: >>> >>> #define GAMG_HASH(key) ((((PetscInt)7)*key)%a_tab->size) >>> >>> We should probably cast everything to (long long) or (unsigned PetscInt) I >>> guess ... I'm not sure how this should be done exactly. Any ideas from the >>> peanut gallery? >> >> Mark, >> >> It should only be changed if we know the exact mechanism that causes the >> failure. It is not obvious to me that just changing >> ((((PetscInt)7)*key)%a_tab->size) to ((((PetscInt64)7)*key)%a_tab->size) >> should matter. >> >> If 7*key > 2B then you can get a negative number and %a_tab->size will still >> be a negative number, which triggers: >> >> ksp/pc/impls/gamg/agg.c: if (flid < 0) >> SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cannot find gid1 in table”); >> >> which is the second error that Pierre gets. I don't fully understand the >> first error but a messed up hash table is certainly a possibility. >> >> And maybe we should cast the hell out of it to be safe: >> >> #define GAMG_HASH(key) >> (PetscInt)((((PetscInt64)7)*(PetscInt64)key)%(PetscInt64)a_tab->size) >> >> I am a bit puzzled that this works. I would think this would be more of a >> problem but maybe everyone just uses 64 bit ints. I have dealt with this >> many times and I am puzzled that I left it in a state that looks so wrong to >> me now. Perhaps Pierre's complicated thing is causing this somehow. >> >> >> >> Barry >> >>> >>> >>> >>> On Sun, Jun 24, 2018 at 2:34 AM Pierre Jolivet <[email protected]> >>> wrote: >>> Hello, >>> Any ideas on how to debug this? >>> [406]PETSC ERROR: key 328214936 not found in table >>> [406]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html >>> for trouble shooting. >>> [406]PETSC ERROR: Petsc Development GIT revision: v3.9.2-603-gceafe64 GIT >>> Date: 2018-06-10 12:46:16 -0500 >>> [406]PETSC ERROR: >>> /ccc/work/cont003/rndm/rndm/FreeFem-sources/src/mpi/FreeFem++-mpi on a >>> arch-linux2-c-debug-bullxmpi named curie2698 by jolivetp Sun Jun 24 >>> 07:06:07 2018 >>> [406]PETSC ERROR: Configure options --with-scalar-type=real >>> --with-hypre-dir=arch-linux2-c-opt-bullxmpi >>> --with-metis-dir=arch-linux2-c-opt-bullxmpi >>> --with-mumps-dir=arch-linux2-c-opt-bullxmpi --with-mkl_cpardiso=1 >>> --with-mkl_pardiso=1 --with-parmetis-dir=arch-linux2-c-opt-bullxmpi >>> --with-ptscotch-dir=arch-linux2-c-opt-bullxmpi >>> --with-sowing-dir=arch-linux2-c-opt-bullxmpi >>> --with-blacs-include=/ccc/products/mkl-18.0.1.163/default/18.0.1.163/mkl/include >>> >>> --with-blacs-lib=/ccc/products/mkl-18.0.1.163/default/18.0.1.163/mkl/lib/intel64/libmkl_blacs_openmpi_lp64.so >>> >>> --with-blaslapack-dir=/ccc/products/mkl-18.0.1.163/default/18.0.1.163/mkl/lib/intel64 >>> --with-x=0 --with-debugging=1 --with-errorchecking=1 >>> --with-mkl_pardiso-dir=/ccc/products/mkl-18.0.1.163/default/18.0.1.163/mkl >>> --with-mkl_cpardiso-dir=/ccc/products/mkl-18.0.1.163/default/18.0.1.163/mkl >>> --with-scalapack-include=/ccc/products/mkl-18.0.1.163/default/18.0.1.163/mkl/include >>> >>> --with-scalapack-lib="[/ccc/products/mkl-18.0.1.163/default/18.0.1.163/mkl/lib/intel64/libmkl_scalapack_lp64.so,/ccc/products/mkl-18.0.1.163/default/18.0.1.163/mkl/lib/intel64/libmkl_blacs_openmpi_lp64.so]" >>> --with-fortran-bindings=0 PETSC_ARCH=arch-linux2-c-debug-bullxmpi >>> [406]PETSC ERROR: #1 PCGAMGHashTableFind() line 106 in >>> /ccc/work/cont003/rndm/rndm/petsc/include/petsc/private/pcgamgimpl.h >>> [406]PETSC ERROR: #2 smoothAggs() line 526 in >>> /ccc/work/cont003/rndm/rndm/petsc/src/ksp/pc/impls/gamg/agg.c >>> [406]PETSC ERROR: #3 PCGAMGCoarsen_AGG() line 970 in >>> /ccc/work/cont003/rndm/rndm/petsc/src/ksp/pc/impls/gamg/agg.c >>> [406]PETSC ERROR: #4 PCSetUp_GAMG() line 518 in >>> /ccc/work/cont003/rndm/rndm/petsc/src/ksp/pc/impls/gamg/gamg.c >>> [406]PETSC ERROR: #5 PCSetUp() line 932 in >>> /ccc/work/cont003/rndm/rndm/petsc/src/ksp/pc/interface/precon.c >>> [406]PETSC ERROR: #6 KSPSetUp() line 381 in >>> /ccc/work/cont003/rndm/rndm/petsc/src/ksp/ksp/interface/itfunc.c >>> >>> For smaller problems, this works fine. Should I compile using 64 bit >>> indices? >>> I’m using -pc_type gamg -pc_gamg_threshold 0.8 -pc_gamg_agg_nsmooths 1 >>> -pc_gamg_sym_graph true -pc_gamg_square_graph 10 >>> >>> Thanks, >>> Pierre >
