[petsc-users] Slepc solver not converging for generalized eigenproblem

[Manav Bhatia]

Hi, 

   I am attempting to compute the eigenvalues of the generalized nonhermitian eigenproblem  

M1 x = lambda M0 x

  M1 and M0 are in the attached text files. The solver is unable to converge with 300 iterations. I have played around with the max it (as high as 1500) and it still is unable to converge. 

  What would be the best way to work around this issue? 

   I would appreciate your help. 

Thanks,
Manav




EPS Object: 1 MPI processes
  type: krylovschur
    50% of basis vectors kept after restart
    using the locking variant
  problem type: generalized non-symmetric eigenvalue problem
  selected portion of the spectrum: smallest eigenvalues in magnitude
  number of eigenvalues (nev): 10
  number of column vectors (ncv): 50
  maximum dimension of projected problem (mpd): 50
  maximum number of iterations: 300
  tolerance: 1e-08
  convergence test: relative to the eigenvalue
BV Object: 1 MPI processes
  type: svec
  51 columns of global length 178
  vector orthogonalization method: classical Gram-Schmidt
  orthogonalization refinement: if needed (eta: 0.7071)
  block orthogonalization method: GS
  doing matmult as a single matrix-matrix product
DS Object: 1 MPI processes
  type: nhep
ST Object: 1 MPI processes
  type: shift
  shift: 0.
  number of matrices: 2
  all matrices have different nonzero pattern
KSP Object: (st_) 1 MPI processes
  type: preonly
  maximum iterations=10000, initial guess is zero
  tolerances:  relative=1e-08, absolute=1e-50, divergence=10000.
  left preconditioning
  using NONE norm type for convergence test
PC Object: (st_) 1 MPI processes
  type: lu
    out-of-place factorization
    tolerance for zero pivot 2.22045e-14
    matrix ordering: nd
    factor fill ratio given 0., needed 0.
      Factored matrix follows:
        Mat Object: 1 MPI processes
          type: seqdense
          rows=178, cols=178
          package used to perform factorization: petsc
          total: nonzeros=31684, allocated nonzeros=31684
          total number of mallocs used during MatSetValues calls =0
  linear system matrix = precond matrix:
  Mat Object: 1 MPI processes
    type: seqdense
    rows=178, cols=178
    total: nonzeros=31684, allocated nonzeros=31684
    total number of mallocs used during MatSetValues calls =0
 Linear eigensolve did not converge due to DIVERGED_ITS; iterations 300
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20180907/c3290eb3/attachment-0003.html>
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: M0.txt
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20180907/c3290eb3/attachment-0002.txt>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20180907/c3290eb3/attachment-0004.html>
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: M1.txt
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20180907/c3290eb3/attachment-0003.txt>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20180907/c3290eb3/attachment-0005.html>