pub fn eigsh<O>(operator: &O, options: EigshOptions) -> Result<Eigensystem>where
O: LinearOperator + ?Sized,Expand description
Selected Hermitian eigenpairs.
Small problems use a dense real-symmetric decomposition. Larger problems use a matrix-free, fully reorthogonalized Lanczos backend; shift targets apply a restarted GMRES inverse without materializing the operator.