X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/GMRES2stage.git/blobdiff_plain/2fc464daa5a04774f5fa10bd96d36c53cc908a4a..3aa4a4a5934c50b8ee7ac223ae1ebc31796c820c:/paper.tex diff --git a/paper.tex b/paper.tex index 54e35d3..2372b61 100644 --- a/paper.tex +++ b/paper.tex @@ -754,7 +754,7 @@ In order to see the influence of our algorithm with only one processor, we first show a comparison with the standard version of GMRES and our algorithm. In Table~\ref{tab:01}, we show the matrices we have used and some of them characteristics. For all the matrices, the name, the field, the number of rows -and the number of nonzero elements is given. +and the number of nonzero elements are given. \begin{table}[htbp] \begin{center} @@ -777,7 +777,7 @@ torso3 & 2D/3D problem & 259,156 & 4,429,042 \\ 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, $max\_iter_{kryl}=30$). $s$ is set to 8. CGLS is +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: $\epsilon_{ls}=1e-40$ and $max\_iter_{ls}=20$. The external precision is set to $\epsilon_{tsirm}=1e-10$. Those experiments have been performed on a Intel(R) @@ -789,7 +789,7 @@ systems obtained with the previous matrices with a GMRES variant and with out 2 stage algorithm are given. In the second column, it can be noticed that either gmres or fgmres is used to solve the linear system. According to the matrices, different preconditioner is used. With TSIRM, the same solver and the same -preconditionner is used. This Table shows that TSIRM can drastically reduce the +preconditionner are used. This Table shows that TSIRM can drastically reduce the number of iterations to reach the convergence when the number of iterations for the normal GMRES is more or less greater than 500. In fact this also depends on tow parameters: the number of iterations to stop GMRES and the number of @@ -823,12 +823,12 @@ torso3 & fgmres / sor & 37.70 & 565 & 34.97 & 510 \\ -In order to perform larger experiments, we have tested some example application +In order to perform larger experiments, we have tested some example applications of PETSc. Those applications are available in the ksp part which is suited for scalable linear equations solvers: \begin{itemize} \item ex15 is an example which solves in parallel an operator using a finite - difference scheme. The diagonal is equals to 4 and 4 extra-diagonals + difference scheme. The diagonal is equal to 4 and 4 extra-diagonals representing the neighbors in each directions is equal to -1. This example is used in many physical phenomena, for example, heat and fluid flow, wave propagation... @@ -940,7 +940,7 @@ the number of iterations. So, the overall benefit of using TSIRM is interesting. \end{table*} -In Table~\ref{tab:04}, some experiments with example ex54 on the Curie architecture are reported +In Table~\ref{tab:04}, some experiments with example ex54 on the Curie architecture are reported. \begin{table*}[htbp]