Hello everyone, this is a question about SLEPc.
The problem that I need to solve is as follows. I have a matrix and I need a full spectrum of it (both eigenvalues and eigenvectors). The regular way is to use Lapack, but it is slow. I decided to try the following: a) compute the bounds of the spectrum using Krylov Schur approach. b) divide the complex eigenvalue plane into rectangular areas, then apply CISS to each area in parallel. However, I found that the solver is missing some eigenvalues, even if my rectangles cover the whole spectral area. My question: can this approach work in principle? If yes, how one can set-up CISS solver to not loose the eigenvalues? Thank you, Michael.
