GMRES(n,k), a version of GMRES for the solution of large sparse linear systems, is introduced. A cycle of GMRES(n,k) consists of n Richardson iterations followed by k iterations of GMRES. Such cycles… (More)

A two-level method for the solution of nite element schemes on locally reened meshes is introduced. The upper bound on the condition number implies, in some cases, mesh-independent convergence, as is… (More)

The present study proposes an unsupervised method for selection of feature subsets, which retain sucient information for classi®cation purposes. Multiple alternative physically feasible partitions… (More)

A two-level method for the solution of locally reened nite element schemes is introduced. It is shown that in the isotropic SPD case the condition number of the preconditioned coeecient matrix is… (More)

A convergence theory for Black-Box Multigrid for a class of SPD problems is presented. Improved versions of Black-Box Multigrid for diiusion problems with discon-tinuous coeecients are deened. A… (More)

Ž . Let F be the family of continued fractions K a r1 , where a s yg , a s p 1 1 p Ž . < < 1 y g g x , p s 2, 3, . . . , with 0 F g F 1, g fixed, and x F 1, p s py1 p p p p p 2, 3, . . . . In this… (More)

Spectral element schemes for the solution of elliptic boundary value problems are considered. Preconditioning methods based on finite difference and finite element schemes are implemented. Numerical… (More)

A two-level analysis method for certain separable problems is introduced. Unlike standard two-level analysis methods, based on Fourier analysis, it is based on spectral analysis, hence applicable to… (More)