Two algorithms for computing the inverse factors of general tridiagonal and pentadiagonal matrices are obtained. Then, these algorithms are used for computing a block ILU preconditioner for the block tridiagonal linear system of equations. Some numerical results are given to show the robustness and efficiency of the preconditioner. The performance of the proposed preconditioner is compared with...

We discuss an iterative method for solving large sparse systems of equations. A hybrid method is introduced which uses ideas both from ILU preconditioning and from multigrid. The resulting preconditioning technique requires the matrix only. A multilevel structure is obtained by using maximal independent sets for graph coarsening. Ideas from [20], [22] are used to construct a sparse Schur comple...

We consider a Newton-Krylov approach for discretized compressible Euler equations. A good preconditioner in the Krylov subspace method is essential for obtaining an efficient solver in such an approach. In this paper we compare point-block-Gauss-Seidel, point-block-ILU and point-block-SPAI preconditioners. It turns out that the SPAI method is not satisfactory for our problem class. The point-bl...

A simple but eecient ILU preconditioning method is described which is well-adapted to Jacobi matrices generated by reaction-diiusion equations modeling diiusion processes in semiconductors. The method is based on a physically motivated subdivision of unknowns into \essential" and \non-essential" ones. The basic idea is to extract a subblock of \essential unknowns" by threshold dropping and to c...

Geotourism potential of Eruku and its environs with emphasis on Ilado hill was appraised.The methods adopted in this work includes geological field mapping interview. From the exercise, rocks include migmatite, gneisses, amphibolite granites, diorite pegmatite. The tourist attractions remnant ancient city wall (Odi Ilu), joining Abumo) hill. also discovered to be an abandoned gate made gold ful...

When powerful machines such as the Cray-2 became available in the late 1980s, a number of researchers investiWe investigate the use of an inexact Newton’s method to solve the potential equations in the transonic regime. As a test case, gated use of exact Newton’s method for solving steady we solve the two-dimensional steady transonic small disturbance state CFD problems. Direct sparse matrix so...

We summarize our experience in solving the three-dimensional carrier continuity equations in our MOS/MES-FET simulator MINIMOS S. First we give a brief overview of the algebraic properties of the coefficient matrices. We show that the matrices are symmetrizable and can be solved by the symmetrized preconditioned CG algorithm. Since the symmetrization matrices are computationally infeasible due ...