6 Nov
2015
6 Nov
'15
9:15 a.m.
Hi Hong,
On 6 Nov 2015, at 16:09, Hong <[email protected]> wrote:
Denis: Do you use shift-and-invert method for solving eigenvalue problem? no, it’s just shift with zero value. So for GHEP one inverts B-matrix.
If so, the linear problems would be extremely ill-conditioned, for which the direct solver, such LU or Cholesky are usually the only working option. Depends on the shift, i would say. In any case the same problem works with jacobi preconditioner no no other changes, so i would not relate it to any settings on SLEPc part.
You may run your petsc/slepc code with option '-ksp_monitor' to observe convergence behavior. Will do, thanks.
Regards, Denis.