X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/GMRES2stage.git/blobdiff_plain/aeb5859d1996432c60c4346b9f961298caa11f5a..99819ede8e00abfefaff7e709c42952c94e96f4c:/paper.tex diff --git a/paper.tex b/paper.tex index b1c6f59..deff6f3 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 @@ -823,7 +823,7 @@ Describe the problems ex15 and ex54 \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 +848,7 @@ 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 +856,7 @@ 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 +872,17 @@ 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