On multigrid methods for the eigenvalue computation of nonselfadjoint elliptic operators (Q2716797)

The authors present two different approaches for the eigenvalue computation of nonselfadjoint operators. The authors first consider a pure multigrid approach very similar to the method proposed by \textit{W. Hackbusch} [Multigrid method and applications (1985; Zbl 0595.65106)]. It relies on the knowledge of a good initial guess on coarse grids which restricts the field of its applications. In the second approach it is proposed a new scheme which couples the Jacobi-Davidson method with a multigrid process based on a defect correction. Numerical experiments for the equation of convection-diffusion considering various Péclet numbers are included and show a drastic overall cost reduction compared to standard pure algebraic methods.