X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/desynchronisation-controle.git/blobdiff_plain/eff67eeac67ec967add0eb7e5e90d500ac32a491..refs/heads/master:/IWCMC14/convergence.tex?ds=sidebyside diff --git a/IWCMC14/convergence.tex b/IWCMC14/convergence.tex index ea4d4c2..b689f99 100644 --- a/IWCMC14/convergence.tex +++ b/IWCMC14/convergence.tex @@ -1,34 +1,44 @@ -Let us first have a discussion on the stop criterion of the citted algorithm. -We claim that even if the variation of the dual function is less than a given -threeshold, this does not ensure that the lifetime has been maximized. +Let us first have a discussion on the stop criterion of the cited algorithm. +We claim that even if the variation of the dual function +(recalled in equation (\ref{eq:dualFunction})) +is less than a given +threshold, this does not ensure that the lifetime has been maximized. Minimizing a function on a multiple domain (as the dual function) -may indeed easilly fall into a local trap because some of introduced +may indeed easily fall into a local trap because some of introduced variables may lead to uniformity of the output. \begin{figure} - to be continued - \caption{Relations between dual function threshold and $q_i$ convergence} + \begin{center} + \includegraphics[scale=0.5]{amplrate.png} + \end{center} + \caption{Relations between dual function variation and convergence of all the $q_i$} \label{fig:convergence:scatterplot} \end{figure} -Experimentations have indeed shown that even if the dual +To explain this, we introduce the maximum amplitude rate $\zeta$ +of the sequence of $q$ which is defined as +$$ +\dfrac{\max_{i \in N} \{q_i\}} +{\min_{i \in N} \{q_i\}}-1. +$$ +The Figure~\ref{fig:convergence:scatterplot} presents +a scatter plot between $\zeta$, which +is represented in $y$-coordinate +with respect to the +value of the threshold for dual function that is represented in +$x$-coordinate. + + +Experiments shown that even if the dual function seems to be constant (variations between two evaluations of this one is less than $10^{-5}$) -not all the $q_i$ have the same value. -For instance, the Figure~\ref{fig:convergence:scatterplot} presents -a scatter plot. - -The maximum amplitude rate of the sequence of $q_i$ --which is -$\frac{\max_{i \in N} q_i} {\min_{i \in N}q_i}-1$-- -is represented in $y$-coordonates - with respect to the -value of the threeshold for dual function that is represented in -$x$-coordonates. -This figure shows that a very small threshold is a necessary condition, but not +not all the $q_i$ have the same value, \textit{i. e.}, $\zeta$ is still large. +For instance, even with a threshold set to $10^{-5}$ there still can be more than +45\% of differences between two $q_i$. +To summarize, a very small threshold is a necessary condition, but not a sufficient criteria to observe convergence of $q_i$. - In the following, we consider the system are $\epsilon$-stable if both -maximum amplitude rate and the dual function are less than a threeshold +maximum amplitude rate and the dual function are less than a threshold $\epsilon$.