X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/hpcc2014.git/blobdiff_plain/f9bb0366521948860427dbe75c159008da521ac3..f1a651fe24fb4fd4daecc0894f43933d1189330b:/hpcc.tex diff --git a/hpcc.tex b/hpcc.tex index e1d916e..aa6eb7d 100644 --- a/hpcc.tex +++ b/hpcc.tex @@ -331,11 +331,27 @@ Algorithm on Figure~\ref{algo:01} shows the main key points of the multisplittin \label{fig:4.1} \end{figure} -The global convergence of the asynchronous multisplitting solver is detected when the clusters of processors have all converged locally. We implemented the global convergence detection process as follows. On each cluster a master processor is designated (for example the processor with rank 1) and masters of all clusters are interconnected by a virtual unidirectional ring network (see Figure~\ref{fig:4.1}). During the resolution, a Boolean token circulates around the virtual ring from a master processor to another until the global convergence is achieved. So starting from the cluster with rank 1, each master processor $i$ sets the token to {\it True} if the local convergence is achieved or to {\it False} otherwise, and sends it to master processor $i+1$. Finally, the global convergence is detected when the master of cluster 1 receives from the master of cluster $L$ a token set to {\it True}. In this case, the master of cluster 1 broadcasts a stop message to masters of other clusters. In this work, the local convergence on each cluster $l$ is detected when the following condition is satisfied +The global convergence of the asynchronous multisplitting solver is detected +when the clusters of processors have all converged locally. We implemented the +global convergence detection process as follows. On each cluster a master +processor is designated (for example the processor with rank 1) and masters of +all clusters are interconnected by a virtual unidirectional ring network (see +Figure~\ref{fig:4.1}). During the resolution, a Boolean token circulates around +the virtual ring from a master processor to another until the global convergence +is achieved. So starting from the cluster with rank 1, each master processor $i$ +sets the token to \textit{True} if the local convergence is achieved or to +\textit{False} otherwise, and sends it to master processor $i+1$. Finally, the +global convergence is detected when the master of cluster 1 receives from the +master of cluster $L$ a token set to \textit{True}. In this case, the master of +cluster 1 broadcasts a stop message to masters of other clusters. In this work, +the local convergence on each cluster $l$ is detected when the following +condition is satisfied \begin{equation*} (k\leq \MI) \text{ or } (\|X_l^k - X_l^{k+1}\|_{\infty}\leq\epsilon) \end{equation*} -where $\MI$ is the maximum number of outer iterations and $\epsilon$ is the tolerance threshold of the error computed between two successive local solution $X_l^k$ and $X_l^{k+1}$. +where $\MI$ is the maximum number of outer iterations and $\epsilon$ is the +tolerance threshold of the error computed between two successive local solution +$X_l^k$ and $X_l^{k+1}$. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% We did not encounter major blocking problems when adapting the multisplitting algorithm previously described to a simulation environment like SimGrid unless some code