On the Use of Inexact Subdomain Solvers in BDDC Preconditioners

Jing Li

Email: li@math.kent.edu
Postal address: Department of Mathematical Sciences, Kent State University, Kent, OH 44242

The BDDC preconditioner is shown to be equivalent to a domain decomposition preconditioner written in terms of solving a partially subassembled finite element problem. The connection of another with the FETI--DP algorithm with a lumped preconditioner is also considered. In the preconditioning step, a Multigrid Method is used to solve the subdomain problems inexactly. Under certain assumptions, it can be established that the iteration count using inexact subdomain solvers essentially remains the same as using exact ones. This talk is based on joint work with Olof Widlund of Courant Institute.