A null space algorithm for mixed nite element approximation
of Darcy's equation
Mario Arioli 1 and Gianmarco Manzini 2
A null space algorithm is considered to solve the augmented system produced by the mixed
nite element approximation of Darcy's Law. The method is based on the combination of
an orthogonal factorisation technique for sparse matrices with an iterative Krylov solver.
The computational e∆ciency of the method relies on a suitable stopping criterion for the
iterative solver. We experimentally investigate its performance on a realistic set of selected
Keywords: Augmented systems, sparse matrices, mixed nite elements.
AMS(MOS) subject classications: 65F05, 65F50.
Current reports available by anonymous ftp to ftp.numerical.rl.ac.uk in directory pub/reports.
1 M.Arioli@rl.ac.uk, Rutherford Appleton Laboratory,
2 email@example.com, IAN - CNR, via Ferrata 1, 27100 Pavia, Italy
Computational Science and Engineering Department
Rutherford Appleton Laboratory
Oxon OX11 0QX