[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.

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?