Olivier Marty 8 years ago
parent
commit
d85ea341b4
1 changed files with 44 additions and 26 deletions
  1. 44 26
      main.tex

+ 44 - 26
main.tex

@@ -213,8 +213,7 @@ discrepancy and this heuristic.
 \label{rand_iter3}
 \label{rand_iter3}
 \end{figure}
 \end{figure}
 
 
-%# TODO sa n'est pas evolutionnaire
-\subsection{Evolutionary heuristic: Simulated annealing and local search}
+\subsection{Local search with simulated annealing}
 The second heuristic implemented is a randomized local search with
 The second heuristic implemented is a randomized local search with
 simulated annealing. This heuristic is inspired by the physical
 simulated annealing. This heuristic is inspired by the physical
 process of annealing in metallurgy.
 process of annealing in metallurgy.
@@ -239,7 +238,7 @@ The whole algorithm is described in the flowchart~\ref{flow_rec}.
 \begin{figure}
 \begin{figure}
  \begin{mdframed}
  \begin{mdframed}
 \includegraphics[scale=0.4]{flow_recuit.pdf}
 \includegraphics[scale=0.4]{flow_recuit.pdf}
-\caption{Flowchart of the simulated annealing local search heuristic}
+\caption{Flowchart of the local search with simulated annealing heuristic}
 \label{flow_rec}
 \label{flow_rec}
 \end{mdframed}
 \end{mdframed}
 \end{figure}
 \end{figure}
@@ -297,7 +296,26 @@ rates for fully random search with 400 iterations.
   \label{iter_sa}
   \label{iter_sa}
 \end{figure}
 \end{figure}
 
 
-\subsection{Genetic (5+5) search}
+\subsection{Genetic $(\mu+\lambda)$ search}
+
+The third heuristic implemented is the $(\mu+\lambda)$ genectic search.
+This heuristic is inspired from the evolution of species: a family
+of $\mu$ genes is known (they are generated randomly at the beginning),
+from which $\lambda$ new genes are derived. A gene is the set of parameters
+we are optimising, i.e. the permutations.
+Each one is derived either from one gene applying a mutation
+(here a transposition of one of the permutations), or from two
+genes applying a crossover : a blending of both genes (the
+algorithm is described in details further). The probability of
+making a mutation is $c$, the third parameter of the algorithm,
+among $\mu$ and $\lambda$. After that, only the $\mu$ best
+genes are kept, according to their fitness, and the process
+can start again.
+
+Because variating over $\mu$ or $\lambda$ does not change fundamentaly
+the algorithm, we have chosen to fix $\mu=\lambda=5$ once and for all,
+which seemed to be a good trade-off between the running time of
+each iteration and the size of the family.
 
 
 
 
 \begin{figure}
 \begin{figure}
@@ -308,23 +326,6 @@ rates for fully random search with 400 iterations.
 \end{mdframed}
 \end{mdframed}
 \end{figure}
 \end{figure}
 
 
-\subsubsection{Dependence on the parameter p}
-First experiments were made to select the value for the crossover parameter
-p. Results are compiled in graphs~\ref{res_gen2},~\ref{res_gen2z},\ref{res_gen3}
-and~\ref{res_gen4}.
-Graph~\ref{res_gen2}, represents the results obtained
-in dimension 2 between 10 and 500 points. The curve obtained is, with no
-surprise again,
-the characteristic curve of the average evolution of the discrepancy we already
-saw with the previous experiments.
-The most interesting part of these results are concentrated --- once again ---
-between 80 and 160 points were the different curves splits.
-The graph~\ref{res_gen2z} is a zoom  of~\ref{res_gen2} in this window, and
-graphs~\ref{res_gen3} and~\ref{res_gen4} are focused directly into it too.
-We remark that in dimension 2, the results are better for $p$ close to $0.5$
-whereas for dimension 3 and 4 the best results are obtained for $p$ closer to
-$0.1$.
-
 \subsubsection{Algorithm of crossover}
 \subsubsection{Algorithm of crossover}
 
 
 We designed a crossover for permutations. The idea is simple: given two
 We designed a crossover for permutations. The idea is simple: given two
@@ -381,32 +382,49 @@ permutations.
 \end{algorithm}
 \end{algorithm}
 
 
 
 
+\subsubsection{Dependence on the parameter $c$}
+First experiments were made to select the value for the crossover parameter
+$c$. Results are compiled in graphs~\ref{res_gen2},~\ref{res_gen2z},\ref{res_gen3}
+and~\ref{res_gen4}.
+Graph~\ref{res_gen2}, represents the results obtained
+in dimension 2 between 10 and 500 points. The curve obtained is, with no
+surprise again,
+the characteristic curve of the average evolution of the discrepancy we already
+saw with the previous experiments.
+The most interesting part of these results are concentrated --- once again ---
+between 80 and 160 points were the different curves splits.
+The graph~\ref{res_gen2z} is a zoom  of~\ref{res_gen2} in this window, and
+graphs~\ref{res_gen3} and~\ref{res_gen4} are focused directly into it too.
+We remark that in dimension 2, the results are better for $c$ close to $0.5$
+whereas for dimension 3 and 4 the best results are obtained for $c$ closer to
+$0.1$.
+
 
 
 \begin{figure}
 \begin{figure}
 \includegraphics[scale=0.3]{Results/res_gen_2.png}
 \includegraphics[scale=0.3]{Results/res_gen_2.png}
-\caption{Dependence on parameter p: D=2}
+\caption{Dependence on parameter $c$: D=2}
   \label{res_gen2}
   \label{res_gen2}
 \end{figure}
 \end{figure}
 
 
 \begin{figure}
 \begin{figure}
 \includegraphics[scale=0.3]{Results/res_gen_2_zoom.png}
 \includegraphics[scale=0.3]{Results/res_gen_2_zoom.png}
-\caption{Dependence on parameter p (zoom): D=2}
+\caption{Dependence on parameter $c$ (zoom): D=2}
 \label{res_gen2z}
 \label{res_gen2z}
 \end{figure}
 \end{figure}
 \begin{figure}
 \begin{figure}
 \includegraphics[scale=0.3]{Results/res_gen_3_zoom.png}
 \includegraphics[scale=0.3]{Results/res_gen_3_zoom.png}
-\caption{Dependence on parameter p: D=3}
+\caption{Dependence on parameter $c$: D=3}
   \label{res_gen3}
   \label{res_gen3}
 \end{figure}
 \end{figure}
 
 
 \begin{figure}
 \begin{figure}
 \includegraphics[scale=0.3]{Results/res_gen_4_zoom.png}
 \includegraphics[scale=0.3]{Results/res_gen_4_zoom.png}
-\caption{Dependence on parameter p: D=4}
+\caption{Dependence on parameter $c$: D=4}
   \label{res_gen4}
   \label{res_gen4}
 \end{figure}
 \end{figure}
 
 
 Once again we investigated the stability
 Once again we investigated the stability
-of the algorithm with regards to the number of iterations.  Once again we
+of the algorithm with regards to the number of iterations. Once again we
 restricted the window between 80 and 180 points were curves are split.
 restricted the window between 80 and 180 points were curves are split.
 The results are compiled in graph~\ref{gen_iter}.
 The results are compiled in graph~\ref{gen_iter}.
 An interesting phenomena can be observed: the error rates are getting really
 An interesting phenomena can be observed: the error rates are getting really