X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/GMRES2stage.git/blobdiff_plain/f2b93de905ad07c8701e6cc195e12da13406d8f3..96dcb243cd0224275446d6d85fab46ed72241a22:/paper.tex diff --git a/paper.tex b/paper.tex index ef0321c..9035059 100644 --- a/paper.tex +++ b/paper.tex @@ -823,13 +823,13 @@ which concludes the induction and the proof. \label{sec:05} -In order to see the influence of our algorithm with only one processor, we first -show a comparison with GMRES or FGMRES and our algorithm. In Table~\ref{tab:01}, -we show the matrices we have used and some of them characteristics. Those -matrices are chosen from the Davis collection of the University of -Florida~\cite{Dav97}. They are matrices arising in real-world applications. For -all the matrices, the name, the field, the number of rows and the number of -nonzero elements are given. +In order to see the behavior of the proposal when considering only one processor, a first +comparison with GMRES or FGMRES and the new algorithm detailed previously has been experimented. +Matrices that have been used with their characteristics (names, fields, rows, and nonzero coefficients) are detailed in +Table~\ref{tab:01}. These latter, which are real-world applications matrices, +have been extracted + from the Davis collection, University of +Florida~\cite{Dav97}. \begin{table}[htbp] \begin{center} @@ -849,8 +849,9 @@ torso3 & 2D/3D problem & 259,156 & 4,429,042 \\ \label{tab:01} \end{center} \end{table} - -The following parameters have been chosen for our experiments. As by default +Chosen parameters are detailed below. +%The following parameters have been chosen for our experiments. +As by default the restart of GMRES is performed every 30 iterations, we have chosen to stop the GMRES every 30 iterations (\emph{i.e.} $max\_iter_{kryl}=30$). $s$ is set to 8. CGLS is chosen to minimize the least-squares problem with the following parameters: @@ -930,8 +931,16 @@ by core. The Juqueen architecture is composed of IBM PowerPC A2 at 1.6 GHz with speed network. +In many situations, using preconditioners is essential in order to find the +solution of a linear system. There are many preconditioners available in PETSc. +For parallel applications all the preconditioners based on matrix factorization +are not available. In our experiments, we have tested different kinds of +preconditioners, however as it is not the subject of this paper, we will not +present results with many preconditioners. In practise, we have chosen to use a +multigrid (mg) and successive over-relaxation (sor). For more details on the +preconditioner in PETSc please consult~\cite{petsc-web-page}. + -{\bf Description of preconditioners}\\ \begin{table*}[htbp] \begin{center}