X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/Krylov_multi.git/blobdiff_plain/93d523a29282f24946a4550b80d133269f3130f2..refs/heads/master:/krylov_multi_reviewed.tex diff --git a/krylov_multi_reviewed.tex b/krylov_multi_reviewed.tex index 02d1aca..7934501 100644 --- a/krylov_multi_reviewed.tex +++ b/krylov_multi_reviewed.tex @@ -84,16 +84,16 @@ thousands of cores are used. Traditional parallel iterative solvers are based on fine-grain computations that frequently require data exchanges between computing nodes and have global -synchronizations that penalize the scalability. Particularly, they are more -penalized on large scale architectures or on distributed platforms composed of -distant clusters interconnected by a high-latency network. It is therefore -imperative to develop coarse-grain based algorithms to reduce the communications -in the parallel iterative solvers. Two possible solutions consists either in -using asynchronous iterative methods~\cite{ref18} or in using multisplitting -algorithms. In this paper, we will reconsider the use of a multisplitting -method. In opposition to traditional multisplitting method that suffer from slow -convergence, as proposed in~\cite{huang1993krylov}, the use of a minimization -process can drastically improve the convergence.\\ +synchronizations that penalize the scalability~\cite{zkcgb+14:ij}. Particularly, +they are more penalized on large scale architectures or on distributed platforms +composed of distant clusters interconnected by a high-latency network. It is +therefore imperative to develop coarse-grain based algorithms to reduce the +communications in the parallel iterative solvers. Two possible solutions +consists either in using asynchronous iterative methods~\cite{ref18} or in using +multisplitting algorithms. In this paper, we will reconsider the use of a +multisplitting method. In opposition to traditional multisplitting method that +suffer from slow convergence, as proposed in~\cite{huang1993krylov}, the use of +a minimization process can drastically improve the convergence.\\ %%% AJOUTE************************ @@ -380,7 +380,7 @@ respectively. The size of the Krylov subspace basis $S$ is fixed to 10 vectors. \begin{figure}[htbp] \centering \begin{tabular}{c} -\includegraphics[width=0.8\textwidth]{weak_scaling_280k} \\ \includegraphics[width=0.8\textwidth]{weak_scaling_280K}\\ +\includegraphics[width=0.8\textwidth]{weak_scaling_280k} \\ \includegraphics[width=0.8\textwidth]{weak_scaling_280K2}\\ \end{tabular} \caption{Weak scaling with 3 blocks of 4 cores each to solve a 3D Poisson problem with approximately 280K components per core} \label{fig:002} @@ -476,7 +476,7 @@ to 115. So it is not different from GMRES. \begin{figure}[htbp] \centering \includegraphics[width=0.7\textwidth]{nb_iter_sec} -\caption{Number of iterations per second with the same parameters as in Table~\ref{tab1} (weak scaling) with only 2 blocks of cores} +\caption{Number of iterations per second with the same parameters as in Table~\ref{tab1} (weak scaling) with only blocks of cores} \label{fig:01} \end{figure}