X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/hpcc2014.git/blobdiff_plain/74faf54391ee09cf05d205964b861e91ee559d74..46669e8faa395b87637d880f68557ff065c78d04:/hpcc.tex?ds=inline diff --git a/hpcc.tex b/hpcc.tex index 1dc732c..7389e3e 100644 --- a/hpcc.tex +++ b/hpcc.tex @@ -4,7 +4,7 @@ \usepackage[utf8]{inputenc} \usepackage{amsfonts,amssymb} \usepackage{amsmath} -\usepackage{algorithm} +%\usepackage{algorithm} \usepackage{algpseudocode} %\usepackage{amsthm} \usepackage{graphicx} @@ -216,8 +216,9 @@ Y_l = B_l - \displaystyle\sum_{\substack{m=1\\ m\neq l}}^{L}A_{lm}X_m \end{equation} is solved independently by a cluster and communications are required to update the right-hand side sub-vector $Y_l$, such that the sub-vectors $X_m$ represent the data dependencies between the clusters. As each sub-system (\ref{eq:4.1}) is solved in parallel by a cluster of processors, our multisplitting method uses an iterative method as an inner solver which is easier to parallelize and more scalable than a direct method. In this work, we use the parallel algorithm of GMRES method~\cite{ref1} which is one of the most used iterative method by many researchers. -\begin{algorithm} -\caption{A multisplitting solver with GMRES method} +\begin{figure} + %%% IEEE instructions forbid to use an algorithm environment here, use figure + %%% instead \begin{algorithmic}[1] \Input $A_l$ (sparse sub-matrix), $B_l$ (right-hand side sub-vector) \Output $X_l$ (solution sub-vector)\vspace{0.2cm} @@ -238,10 +239,23 @@ is solved independently by a cluster and communications are required to update t \State \Return $X_l^k$ \EndFunction \end{algorithmic} +\caption{A multisplitting solver with GMRES method} \label{algo:01} -\end{algorithm} +\end{figure} -Algorithm~\ref{algo:01} shows the main key points of the multisplitting method to solve a large sparse linear system. This algorithm is based on an outer-inner iteration method where the parallel synchronous GMRES method is used to solve the inner iteration. It is executed in parallel by each cluster of processors. For all $l,m\in\{1,\ldots,L\}$, the matrices and vectors with the subscript $l$ represent the local data for cluster $l$, while $\{A_{lm}\}_{m\neq l}$ are off-diagonal matrices of sparse matrix $A$ and $\{X_m\}_{m\neq l}$ contain vector elements of solution $x$ shared with neighboring clusters. At every outer iteration $k$, asynchronous communications are performed between processors of the local cluster and those of distant clusters (lines $6$ and $7$ in Algorithm~\ref{algo:01}). The shared vector elements of the solution $x$ are exchanged by message passing using MPI non-blocking communication routines. +Algorithm on Figure~\ref{algo:01} shows the main key points of the +multisplitting method to solve a large sparse linear system. This algorithm is +based on an outer-inner iteration method where the parallel synchronous GMRES +method is used to solve the inner iteration. It is executed in parallel by each +cluster of processors. For all $l,m\in\{1,\ldots,L\}$, the matrices and vectors +with the subscript $l$ represent the local data for cluster $l$, while +$\{A_{lm}\}_{m\neq l}$ are off-diagonal matrices of sparse matrix $A$ and +$\{X_m\}_{m\neq l}$ contain vector elements of solution $x$ shared with +neighboring clusters. At every outer iteration $k$, asynchronous communications +are performed between processors of the local cluster and those of distant +clusters (lines $6$ and $7$ in Figure~\ref{algo:01}). The shared vector +elements of the solution $x$ are exchanged by message passing using MPI +non-blocking communication routines. \begin{figure} \centering