[Libmesh-users] generalized eigenvalue problem

Hi David, Thank you very much for reply! I have checked the lapack documentation and the respective petsc C-files beforehand but it did not help very much. I am solving the eigenvalue problem to compute the constant in the trace theorem and hence the matrix A is associated with the integral

Re: [Libmesh-users] generalized eigenvalue problem with one singular matrix

Hi Kathrin, I'm not sure why lapack would fail here, you could try to look up that error "Error in Lapack xGGES 260" in the lapack documentation? In my experience, lapack works robustly unless the problem is "too large": lapack treats the matrices as dense, so you "hit a wall" at some point an

[Libmesh-users] generalized eigenvalue problem with one singular matrix

Hi all, I am trying to solve a generalized eigenvalue problem based on eigenproblems_ex2.C, where the matrix A is singular (only a few entries are different from zero) and the matrix B is symmetric and positive definite and I am using lapack. I get convergence for a mesh of 30 \times 5 \times