+\subsection{Experimental study}\r
+\r
+\subsubsection{Definition of the polynomial used}\r
+We use a polynomial of the following form for which the\r
+roots are distributed on 2 distinct circles:\r
+\begin{equation}\r
+ \forall \alpha_{1} \alpha_{2} \in C,\forall n_{1},n_{2} \in N^{*}; P(z)= (z^{n^{1}}-\alpha_{1})(z^{n^{2}}-\alpha_{2})\r
+\end{equation}\r
+\r
+This form makes it possible to associate roots having two\r
+different modules and thus to work on a polynomial constitute\r
+of four non zero terms.\r
+\\\r
+ An other form of the polynomial to obtain more non zero terms is:\r
+\begin{equation}\r
+ \forall \alpha_{i} \in C,\forall n_{i}\in N^{*}; P(z)= \sum^{i=1}_{p}(z^{n^{i}}-\alpha_{i})\r
+\end{equation}\r
+\r
+with this formula, we can have until 2p non zero terms.\r
+\r
+\subsubsection{The study condition} \r
+In order to have representative average values, for each\r
+point of our curves we measured the roots finding of 10\r
+different polynomials.\r
+\r
+The our experiences results concern two parameters which are\r
+the polynomial degree and the execution time of our program\r
+to converge on the solution. The polynomial degree allows us\r
+to validate that our algorithm is powerful with high degree\r
+polynomials. The execution time remains the\r
+element-key which justifies our work of parallelization.\r
+ For our tests we used a CPU Intel(R) Xeon(R) CPU\r
+E5620@2.40GHz and a GPU Tesla C2070 (with 6 Go of ram)\r
+\r
+\subsubsection{Comparative study}\r
+We initially carried out the convergence of Aberth algorithm with various sizes of polynomial, in second we evaluate the influence of the size of the threads per block....\r
+\r
+\paragraph{The convergence of Aberth algorithm}\r
+\r
+\begin{table}[!h]\r
+ \centering\r
+ \begin{tabular} {|R{2cm}|L{2.5cm}|L{2.5cm}|L{1.5cm}|L{1.5cm}|}\r
+ \hline Polynomial's degrees & $T_{exe}$ on CPU & $T_{exe}$ on GPU & CPU iteration & GPU iteration\\\r
+ \hline 5000 & 1.90 & 0.40 & 18 & 17\\\r
+ \hline 50000 & 172.723 & 3.92 & 21 & 18\\\r
+ \hline 500000 & -- & 497.109 & -- & 24\\\r
+ \hline 1000000 & -- & 1524,51 & -- & 24\\\r
+ \hline \r
+ \end{tabular}\r
+ \caption{the convergence of Aberth algorithm}\r
+ \label{tab:theConvergenceOfAberthAlgorithm}\r
+\end{table}\r
+ \r
+\paragraph{The impact of the thread's number into the convergence of Aberth algorithm}\r
+\r
+\begin{table}[!h]\r
+ \centering\r
+ \begin{tabular} {|R{2.5cm}|L{2.5cm}|L{2.5cm}|}\r
+ \hline Tread's numbers & Execution time &Number of iteration\\\r
+ \hline 1024 & 523 & 27\\\r
+ \hline 512 & 449.426 & 24\\\r
+ \hline 256 & 440.805 & 24\\\r
+ \hline 128 & 456.175 & 22\\\r
+ \hline 64 & 472.862 & 23\\\r
+ \hline 32 & 830.152 & 24\\\r
+ \hline 8 & 2632.78 & 23 \\\r
+ \hline\r
+ \end{tabular}\r
+ \caption{The impact of the thread's number into the convergence of Aberth algorithm}\r
+ \label{tab:Theimpactofthethread'snumberintotheconvergenceofAberthalgorithm}\r
+ \r
+\end{table}\r
+\r
+\paragraph{A comparative study between Aberth and Durand\-kerner algorithm}\r
+\begin{table}[htbp]\r
+ \centering\r
+ \begin{tabular} {|R{2cm}|L{2.5cm}|L{2.5cm}|L{1.5cm}|L{1.5cm}|}\r
+ \hline Polynomial's degrees & Aberth $T_{exe}$ & D-Kerner $T_{exe}$ & Aberth iteration & D-Kerner iteration\\\r
+ \hline 5000 & 0.40 & 3.42 & 17 & 138 \\\r
+ \hline 50000 & 3.92 & 385.266 & 17 & 823\\\r
+ \hline 500000 & 497.109 & 4677.36 & 24 & 214\\\r
+ \hline \r
+ \end{tabular}\r
+ \caption{Aberth algorith compare to Durand-Kerner algorithm}\r
+ \label{tab:AberthAlgorithCompareToDurandKernerAlgorithm}\r
+\end{table}\r
+\r
+\r