On Fri, Oct 19, 2018 at 5:01 AM Jan Grießer <griesser....@googlemail.com> wrote:
> With more than 1 MPI process you mean i should use spectrum slicing in > divide the full problem in smaller subproblems? > The --with-64-bit-indices is not a possibility for me since i configured > petsc with mumps, which does not allow to use the 64-bit version (At least > this was the error message when i tried to configure PETSc ) > I believe you can replace MUMPS with SuperLU_dist for 64-bit ints. Matt > Am Mi., 17. Okt. 2018 um 18:24 Uhr schrieb Jose E. Roman < > jro...@dsic.upv.es>: > >> To use BVVECS just add the command-line option -bv_type vecs >> This causes to use a separate Vec for each column, instead of a single >> long Vec of size n*m. But it is considerably slower than the default. >> >> Anyway, for such large problems you should consider using more than 1 MPI >> process. In that case the error may disappear because the local size is >> smaller than 768000. >> >> Jose >> >> >> > El 17 oct 2018, a las 17:58, Matthew Knepley <knep...@gmail.com> >> escribió: >> > >> > On Wed, Oct 17, 2018 at 11:54 AM Jan Grießer < >> griesser....@googlemail.com> wrote: >> > Hi all, >> > i am using slepc4py and petsc4py to solve for the smallest real >> eigenvalues and eigenvectors. For my test cases with a matrix A of the size >> 30k x 30k solving for the smallest soutions works quite well, but when i >> increase the dimension of my system to around A = 768000 x 768000 or 3 >> million x 3 million and ask for the smallest real 3000 (the number is >> increasing with increasing system size) eigenvalues and eigenvectors i get >> the output (for the 768000): >> > The product 4001 times 768000 overflows the size of PetscInt; consider >> reducing the number of columns, or use BVVECS instead >> > i understand that the requested number of eigenvectors and eigenvalues >> is causing an overflow but i do not understand the solution of the problem >> which is stated in the error message. Can someone tell me what exactly >> BVVECS is and how i can use it? Or is there any other solution to my >> problem ? >> > >> > You can also reconfigure with 64-bit integers: --with-64-bit-indices >> > >> > Thanks, >> > >> > Matt >> > >> > Thank you very much in advance, >> > Jan >> > >> > >> > >> > -- >> > 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/ >> >> -- 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.cse.buffalo.edu/~knepley/>