X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/Krylov_multi.git/blobdiff_plain/2ba13b434c9d2aab12becfb44463be0a8bea74e7..b7730f90b7bda6c50247f984c438b3fb1fde97bf:/krylov_multi.tex?ds=sidebyside diff --git a/krylov_multi.tex b/krylov_multi.tex index 98b8949..2d0bc69 100644 --- a/krylov_multi.tex +++ b/krylov_multi.tex @@ -75,11 +75,14 @@ traditional multisplitting method that suffer from slow convergence, as proposed in~\cite{huang1993krylov}, the use of a minimization process can drastically improve the convergence. +The paper is organized as follows. First in Section~\ref{sec:02} is given some related works and the main principle of multisplitting methods. The, in Section~\ref{sec:03} is presented the algorithm of our Krylov multisplitting method based on inner-outer iterations. Finally, in Section~\ref{sec:04}, the parallel experiments on Hector architecture show the performances of the Krylov multisplitting algorithm compared to the classical GMRES algorithm to solve a 3D Poisson problem. + %%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%% -\section{Related works and presention of the multisplitting method} +\section{Related works and presentation of the multisplitting method} +\label{sec:02} A general framework for studying parallel multisplitting has been presented in~\cite{o1985multi} by O'Leary and White. Convergence conditions are given for the most general case. Many authors improved multisplitting algorithms by proposing @@ -142,6 +145,7 @@ In the case where the diagonal weighting matrices $E_\ell$ have only zero and on %%%%%%%%%%%%%%%%%%%%%%%% \section{A two-stage method with a minimization} +\label{sec:03} Let $Ax=b$ be a given large and sparse linear system of $n$ equations to solve in parallel on $L$ clusters of processors, physically adjacent or geographically distant, where $A\in\mathbb{R}^{n\times n}$ is a square and non-singular matrix, $x\in\mathbb{R}^{n}$ is the solution vector and $b\in\mathbb{R}^{n}$ is the right-hand side vector. The multisplitting of this linear system is defined as follows \begin{equation} \left\{ @@ -253,6 +257,7 @@ The main key points of our Krylov multisplitting method to solve a large sparse %%%%%%%%%%%%%%%%%%%%%%%% \section{Experiments} +\label{sec:04} In order to illustrate the interest of our algorithm. We have compared our algorithm with the GMRES method which is a very well used method in many situations. We have chosen to focus on only one problem which is very simple to