X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/GMRES2stage.git/blobdiff_plain/2e6154ec59cf3bf10609cc7de399aa809e9b44ea..f906225644f3d763193e909f019cce9455984280:/paper.tex diff --git a/paper.tex b/paper.tex index 8ffd387..e7e7e0d 100644 --- a/paper.tex +++ b/paper.tex @@ -354,6 +354,7 @@ \usepackage{amsmath} \usepackage{amssymb} \usepackage{multirow} +\usepackage{graphicx} \algnewcommand\algorithmicinput{\textbf{Input:}} \algnewcommand\Input{\item[\algorithmicinput]} @@ -583,8 +584,7 @@ performances. The present paper is organized as follows. In Section~\ref{sec:02} some related works are presented. Section~\ref{sec:03} presents our two-stage algorithm using a least-square residual minimization. Section~\ref{sec:04} describes some -convergence results on this method. In Section~\ref{sec:05}, parallization -details of TSARM are given. Section~\ref{sec:06} shows some experimental +convergence results on this method. Section~\ref{sec:05} shows some experimental results obtained on large clusters of our algorithm using routines of PETSc toolkit. Finally Section~\ref{sec:06} concludes and gives some perspectives. %%%********************************************************* @@ -615,7 +615,7 @@ points of our solver are given in Algorithm~\ref{algo:01}. In order to accelerate the convergence, the outer iteration periodically applies a least-square minimization on the residuals computed by the inner solver. The -inner solver is a Krylov based solver which does not required to be changed. +inner solver is based on a Krylov method which does not require to be changed. At each outer iteration, the sparse linear system $Ax=b$ is solved, only for $m$ iterations, using an iterative method restarting with the previous solution. For @@ -680,18 +680,6 @@ To summarize, the important parameters of TSARM are: \item $\epsilon_{ls}$ the threshold to stop the least-square method \end{itemize} -%%%********************************************************* -%%%********************************************************* - -\section{Convergence results} -\label{sec:04} - - - -%%%********************************************************* -%%%********************************************************* -\section{Parallelization} -\label{sec:05} The parallelisation of TSARM relies on the parallelization of all its parts. More precisely, except the least-square step, all the other parts are @@ -733,10 +721,21 @@ In each iteration of CGLS, there is two matrix-vector multiplications and some classical operations: dots, norm, multiplication and addition on vectors. All these operations are easy to implement in PETSc or similar environment. + + +%%%********************************************************* +%%%********************************************************* + +\section{Convergence results} +\label{sec:04} + + + + %%%********************************************************* %%%********************************************************* \section{Experiments using petsc} -\label{sec:06} +\label{sec:05} In order to see the influence of our algorithm with only one processor, we first @@ -856,6 +855,17 @@ but they are not scalable with many cores. \end{table*} +\begin{figure} +\centering + \includegraphics[width=0.45\textwidth]{nb_iter_sec_ex15_juqueen} +\caption{Number of iterations per second with ex15 and the same parameters than in Table~\ref{tab:03}} +\label{fig:01} +\end{figure} + + + + + \begin{table*} \begin{center} \begin{tabular}{|r|r|r|r|r|r|r|r|r|} @@ -913,7 +923,7 @@ but they are not scalable with many cores. %%%********************************************************* %%%********************************************************* \section{Conclusion} -\label{sec:07} +\label{sec:06} %The conclusion goes here. this is more of the conclusion %%%********************************************************* %%%*********************************************************