On Mon, Sep 5, 2011 at 4:08 PM, Kristen Eisenberg < [email protected]> wrote:

[petsc-users] SLEPc generalized eigenvalue problem question?

I create 2 matrices using:

MatCreateSeqDense(PETSC_COMM_SELF, n, n, Ka, &A); MatCreateSeqDense(PETSC_COMM_SELF, n, n, Kb, &B); These matrices are 99% zeros ( 16,016,004 entries and 18660 non-zeros). They are symmetric and real. Their tri-diagonal elements are non-zero plus a few other entries.

You would get better performance and use less memory if you made these matrices of type MATAIJ. Matt

I tried to use ex7 for the generalized eigenvalue problem:

./ex7.exe -f1 k.dat -f2 m.dat -eps_gen_hermitian -eps_smallest_real > x.out 2>&1

without specifying an EPS and get:

Generalized eigenproblem stored in file.

Reading REAL matrices from binary files... Number of iterations of the method: 500 Number of linear iterations of the method: 4009 Solution method: krylovschur

Number of requested eigenvalues: 1 Stopping condition: tol=1e-07, maxit=500 Number of converged approximate eigenpairs: 0

Is krylovschur inappropriate for this problem or have I set up the problem incorrectly by using MatCreateSeqDense(...) to create the matrix input files in PETSc binary form?

Kristen Eisenberg Billige Flüge Marketing GmbH Emanuelstr. 3, 10317 Berlin Deutschland Telefon: +49 (33) 5310967 Email: utebachmeier at gmail.com Site: http://flug.airego.de - Billige Flüge vergleichen

-- 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