No, I mean to run in parallel:

$ mpiexec -n 8 python ex1.py 

Jose


> El 19 oct 2018, a las 11:01, Jan Grießer <griesser....@googlemail.com> 
> escribió:
> 
> 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 )
> 
> 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/
> 

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