X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/rce2015.git/blobdiff_plain/ca1429f05161a13a6c9cc1eb4a62dcb8217c06d2..f191ea095298626cf15138076b2e26ee4dec9b15:/paper.tex diff --git a/paper.tex b/paper.tex index ab8f9ab..24ddab9 100644 --- a/paper.tex +++ b/paper.tex @@ -569,22 +569,33 @@ The execution times between both algorithms is significant with different grid a \includegraphics[width=100mm]{cluster_x_nodes_nx_150_and_nx_170.pdf} \end{center} \caption{Various grid configurations with the matrix sizes 150$^3$ and 170$^3$} +\LZK{CE, la légende de la Figure 3 est trop large. Remplacer les N$_x\times$N$_y\times$N$_z$ par $Mat1$=150$^3$ et $Mat2$=170$^3$ comme dans la Table 1} \label{fig:01} \end{figure} \subsubsection{Simulations for two different inter-clusters network speeds\\} - -In this section, the experiments compare the behavior of the algorithms running on a -speeder inter-cluster network (N2) and also on a less performant network (N1) respectively defined in the test conditions Table~\ref{tab:02}. -%\RC{Il faut définir cela avant...} -Figure~\ref{fig:02} shows that end users will reduce the execution time -for both algorithms when using a grid architecture like 4 $\times$ 16 or 8 $\times$ 8: the reduction factor is around $2$. The results depict also that when -the network speed drops down (variation of 12.5\%), the difference between the two Multisplitting algorithms execution times can reach more than 25\%. +In Figure~\ref{fig:02} we present the execution times of both algorithms to +solve a 3D Poisson problem of size $150^3$ on two different simulated network +$N1$ and $N2$ (see Table~\ref{tab:01}). As previously mentioned, we can see from +this figure that the Krylov two-stage algorithm is sensitive to the number of +clusters (i.e. it is better to have a small number of clusters). However, we can +notice an interesting behavior of the Krylov two-stage algorithm. It is less +sensitive to bad network bandwidth and latency for the inter-clusters links than +the GMRES algorithms. This means that the multisplitting methods are more +efficient for distributed systems with high latency networks. + +%% In this section, the experiments compare the behavior of the algorithms running on a +%% speeder inter-cluster network (N2) and also on a less performant network (N1) respectively defined in the test conditions Table~\ref{tab:02}. +%% %\RC{Il faut définir cela avant...} +%% Figure~\ref{fig:02} shows that end users will reduce the execution time +%% for both algorithms when using a grid architecture like 4 $\times$ 16 or 8 $\times$ 8: the reduction factor is around $2$. The results depict also that when +%% the network speed drops down (variation of 12.5\%), the difference between the two Multisplitting algorithms execution times can reach more than 25\%. \begin{figure}[t] \centering \includegraphics[width=100mm]{cluster_x_nodes_n1_x_n2.pdf} \caption{Various grid configurations with networks $N1$ vs. $N2$} +\LZK{CE, remplacer les ``,'' des décimales par un ``.''} \label{fig:02} \end{figure} @@ -601,6 +612,19 @@ the network speed drops down (variation of 12.5\%), the difference between t + + + + + + + + + + + + +