Yuri Kuznetsov and Konstantin Lipnikov (2002)
Fast Separable Solvers For Mixed Finie Element Methods And Applications
Journal of Numerical Mathematics, Volume 10(2):pp.137-155.
A separable preconditioner for solution of elliptic equations in the mixed-hybrid form is proposed and studied. The problem is discretized on logically rectangular (d=2 or 3) meshes with the lowest order Raviart-Thomas finite elements. The arithmetical complexity of the preconditioner is O(n \ln^d-1 n). Results of numerical experiments are presented.