The paper suggests a new approach to construction of preconditioned and convergence rate estimates for iterative methods to solve simultaneous linear algebraic equations arising in finite element approximations of elliptic problems. The approach is based on the decomposition of the original mesh domain into superelements. It is proved that for many important practical problems the convergence rate estimates of the methods considered do not depend on the mesh, and also on coefficients and boundary conditions of the original differential problem.
Jfl[_iJ=l OXiOXj J J Flwhere Γ χ = 3Ω/Γ 0 , and the coefficients a ij9 b and σ are piece wise-smooth bounded functions and, moreover, b and σ are nonnegative. Consider for a given function /eL 2 = ί. 2 (Ω) the following variational problem: find ueV such that φ, !>) = (/, t?) VueK (0.2)Here, (·,·) stands for the standard scalar product in L 2 . In what follows, we consider independently two cases. First, it is the Neumann problem for Γ 0 = 0, b = 0 in Ω, σ = 0 on Γ! and the function / satisfies the condition | Ω /αΩ = 0. In this case, the solution to problem (0.2) does exist and is uniquely defined, for example, under the assumption Brought to you by | University of Arizona Authenticated Download Date | 7/8/15 10:09 AM