In this paper, we present a block version of incomplete LU preconditioner which is computed as the by-product of block A-biconjugation process. The pivot entries of this block preconditioner are one by one or two by two blocks. The L and U factors of this block preconditioner are computed separately. The block pivot selection of this preconditioner is inherited from one of the block versions of...

To solve saddle point systems efficiently, several preconditioners have been published. There are many methods for constructing preconditioners for linear systems from saddle point problems, for instance, the relaxed dimensional factorization (RDF) preconditioner and the augmented Lagrangian (AL) preconditioner are used for both steady and unsteady Navier-Stokes equations. In this paper we comp...

in this paper, we will present a modification of the preconditioned aor-type method for solving the linear system. a theorem is given to show the convergence rate of modification of the preconditioned aor methods that can be enlarged than the convergence aor method.

In this research, a sub-array preconditioner is applied to improve the convergence of conjugate gradient (CG) iterative solver in the fast multipole method and fast Fourier transform (FMM-FFT) implementation on a large-scale finite periodic array antenna with arbitrary geometry elements. The performance of the sub-array preconditioner is compared with the near-group preconditioner in the array ...

In an earlier paper preconditioning of stationary Stokes-constrained optimal control problems has been considered. In this article we construct an efficient preconditioner for solving the algebraic systems arising from discretized optimal control problems with time-periodic Stokes equations. A simplified analysis of the derivation of the preconditioner and its properties is presented. The preco...

A new parallel symmetric successive over-relaxation (PSSOR) preconditioner is proposed in this paper by the multi-type partition techniques introduced in SIAM J. Scientific Computing 20, 2006, pp. 1513-1533. In a general matrix expression, it is proved to be symmetric and positive-definite if the coefficient matrix of a linear system is symmetric and positive-definite. It is also proved to be e...

In this paper, a block LU preconditioner for saddle point problems is presented. The main diierence between the approach presented here and that of other studies is that an explicit, accurate approximation of the Schur complement matrix is eeciently computed. This is used to compute a preconditioner to the Schur complement matrix that in turn deenes a preconditioner for a global iteration. The ...

In this paper we present a fast iterative image superresolution algorithm using preconditioned conjugate gradient method. To avoid explicitly computing the tolerance in the inverse filter based preconditioner scheme, a new Wiener filter based preconditioner for the conjugate gradient method is proposed to speed up the convergence. The circulant-block structure of the preconditioner allows effic...

We introduce a method for constructing a polynomial preconditioner using a nonlinear least squares (NLLS) algorithm. We show that this polynomial-based NLLS-optimized (PBNO) preconditioner significantly improves the performance of 2-D continuous Galerkin (CG) and discontinuous Galerkin (DG) fluid dynamical research models when run in an implicit-explicit time integration mode. When employed in ...