X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/GMRES2stage.git/blobdiff_plain/aeb5859d1996432c60c4346b9f961298caa11f5a..124fbe31852f69cefa44e364e767c5e0e07ef670:/paper.tex diff --git a/paper.tex b/paper.tex index b1c6f59..fb68702 100644 --- a/paper.tex +++ b/paper.tex @@ -431,9 +431,9 @@ convergence of Krylov iterative methods, typically those of GMRES variants. The principle of our approach is to build an external iteration over the Krylov method and to save the current residual frequently (for example, for each restart of GMRES). Then after a given number of outer iterations, a minimization -step is applied on the matrix composed of the save residuals in order to compute -a better solution and make a new iteration if necessary. We prove that our -method has the same convergence property than the inner method used. Some +step is applied on the matrix composed of the saved residuals in order to +compute a better solution and make a new iteration if necessary. We prove that +our method has the same convergence property than the inner method used. Some experiments using up to 16,394 cores show that compared to GMRES our algorithm can be around 7 times faster. \end{abstract} @@ -793,7 +793,7 @@ minimization. \begin{tabular}{|c|c|r|r|r|r|} \hline - \multirow{2}{*}{Matrix name} & Solver / & \multicolumn{2}{c|}{gmres variant} & \multicolumn{2}{c|}{2 stage CGLS} \\ + \multirow{2}{*}{Matrix name} & Solver / & \multicolumn{2}{c|}{GMRES} & \multicolumn{2}{c|}{TSARM CGLS} \\ \cline{3-6} & precond & Time & \# Iter. & Time & \# Iter. \\\hline \hline @@ -816,14 +816,25 @@ torso3 & fgmres / sor & 37.70 & 565 & 34.97 & 510 \\ Larger experiments ....\\ -Describe the problems ex15 and ex54 +In the following we describe the applications of PETSc we have experimented. 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 a 2D homogeneous + Laplacian. Thediagonal is equals 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 exemple, heat and fluid flow, wave propagation... +\item +\end{itemize} + + + + \begin{table*} \begin{center} \begin{tabular}{|r|r|r|r|r|r|r|r|r|} \hline - nb. cores & precond & \multicolumn{2}{c|}{gmres variant} & \multicolumn{2}{c|}{2 stage CGLS} & \multicolumn{2}{c|}{2 stage LSQR} & best gain \\ + nb. cores & precond & \multicolumn{2}{c|}{GMRES} & \multicolumn{2}{c|}{TSARM CGLS} & \multicolumn{2}{c|}{TSARM LSQR} & best gain \\ \cline{3-8} & & Time & \# Iter. & Time & \# Iter. & Time & \# Iter. & \\\hline \hline 2,048 & mg & 403.49 & 18,210 & 73.89 & 3,060 & 77.84 & 3,270 & 5.46 \\ @@ -848,7 +859,7 @@ Describe the problems ex15 and ex54 \begin{tabular}{|r|r|r|r|r|r|r|r|r|} \hline - nb. cores & threshold & \multicolumn{2}{c|}{gmres variant} & \multicolumn{2}{c|}{2 stage CGLS} & \multicolumn{2}{c|}{2 stage LSQR} & best gain \\ + nb. cores & threshold & \multicolumn{2}{c|}{GMRES} & \multicolumn{2}{c|}{TSARM CGLS} & \multicolumn{2}{c|}{TSARM LSQR} & best gain \\ \cline{3-8} & & Time & \# Iter. & Time & \# Iter. & Time & \# Iter. & \\\hline \hline 2,048 & 8e-5 & 108.88 & 16,560 & 23.06 & 3,630 & 22.79 & 3,630 & 4.77 \\ @@ -856,7 +867,7 @@ Describe the problems ex15 and ex54 4,096 & 7e-5 & 160.59 & 22,530 & 35.15 & 5,130 & 29.21 & 4,350 & 5.49 \\ 4,096 & 6e-5 & 249.27 & 35,520 & 52.13 & 7,950 & 39.24 & 5,790 & 6.35 \\ 8,192 & 6e-5 & 149.54 & 17,280 & 28.68 & 3,810 & 29.05 & 3,990 & 5.21 \\ - 8,192 & 5e-5 & 792.11 & 109,590 & 76.83 & 10,470 & 65.20 & 9,030 & 12.14 \\ + 8,192 & 5e-5 & 785.04 & 109,590 & 76.07 & 10,470 & 69.42 & 9,030 & 11.30 \\ 16,384 & 4e-5 & 718.61 & 86,400 & 98.98 & 10,830 & 131.86 & 14,790 & 7.26 \\ \hline @@ -872,17 +883,17 @@ Describe the problems ex15 and ex54 \begin{table*} \begin{center} -\begin{tabular}{|r|r|r|r|r|r|r|r|} +\begin{tabular}{|r|r|r|r|r|r|r|r|r|r|r|} \hline - nb. cores & \multicolumn{2}{c|}{gmres variant} & \multicolumn{2}{c|}{2 stage CGLS} & \multicolumn{2}{c|}{2 stage LSQR} & best gain \\ -\cline{2-7} - & Time & \# Iter. & Time & \# Iter. & Time & \# Iter. & \\\hline \hline - 512 & 3,969.69 & 33,120 & 709.57 & 5,790 & 622.76 & 5,070 & \\ - 1024 & 1,530.06 & 25,860 & 290.95 & 4,830 & 307.71 & 5,070 & \\ - 2048 & 919.62 & 31,470 & 237,52 & 8,040 & 194.22 & 6,510 & \\ - 4096 & 405.60 & 28,380 & 111.67 & 7,590 & 91.72 & 6,510 & \\ - 8192 & 785.04 & 109,590 & 76.07 & 10,470 & 69,42 & 9,030 & \\ + nb. cores & \multicolumn{2}{c|}{GMRES} & \multicolumn{2}{c|}{TSARM CGLS} & \multicolumn{2}{c|}{TSARM LSQR} & best gain & \multicolumn{3}{c|}{efficiency} \\ +\cline{2-7} \cline{9-11} + & Time & \# Iter. & Time & \# Iter. & Time & \# Iter. & & GMRES & TS CGLS & TS LSQR\\\hline \hline + 512 & 3,969.69 & 33,120 & 709.57 & 5,790 & 622.76 & 5,070 & 6.37 & 1 & 1 & 1 \\ + 1024 & 1,530.06 & 25,860 & 290.95 & 4,830 & 307.71 & 5,070 & 5.25 & 1.30 & 1.21 & 1.01 \\ + 2048 & 919.62 & 31,470 & 237.52 & 8,040 & 194.22 & 6,510 & 4.73 & 1.08 & .75 & .80\\ + 4096 & 405.60 & 28,380 & 111.67 & 7,590 & 91.72 & 6,510 & 4.42 & 1.22 & .79 & .84 \\ + 8192 & 785.04 & 109,590 & 76.07 & 10,470 & 69.42 & 9,030 & 11.30 & .32 & .58 & .56 \\ \hline