new

[kahina_paper1.git] / paper.tex

diff --git a/paper.tex b/paper.tex
index 384ff8bd6b4f41018c378b2ac329975295029649..448aa4fe345d3bd96af44e694ee7b91246bcb042 100644 (file)
--- a/paper.tex
+++ b/paper.tex
@@ -655,7 +655,6 @@ significant).
 
 
 
 
 
 

-%%HIER END MY REVISIONS (SIDER)

 \section{Experimental study}
 \label{sec6}
 %\subsection{Definition of the used polynomials }
 \section{Experimental study}
 \label{sec6}
 %\subsection{Definition of the used polynomials }


@@ -724,14 +723,13 @@ on the GPU is faster than those implemented on the CPU.
 
 This is due to the GPU ability to compute the data-parallel functions
 faster than its CPU counterpart. However, the execution time for the
 
 This is due to the GPU ability to compute the data-parallel functions
 faster than its CPU counterpart. However, the execution time for the

-CPU (4 cores) implementation exceed 5,000 s for 250,000 degrees
-polynomials, in counterpart the GPU implementation for the same
-polynomials not reach 100 s, more than again, with an execution time
-under to 2,500 s CPU (4 cores) implementation can resolve With the GPU
-we can solve very high degrees polynomials very quickly up to degree
+CPU (4 cores) implementation exceed 5,000s for 250,000 degrees
+polynomials. In counterpart, the GPU implementation for the same
+polynomials do not take more 100s. With the GPU
+we can solve high degrees polynomials very quickly up to degree

 of 1,000,000. We can also notice that the GPU implementation are
 almost 47 faster then those implementation on the CPU (4
 of 1,000,000. We can also notice that the GPU implementation are
 almost 47 faster then those implementation on the CPU (4

-cores). However the CPU(4 cores) implementation are almost 4 faster
+cores). However the CPU (4 cores) implementation are almost 4 faster

 then his implementation on CPU (1 core). Furthermore, the number of
 iterations and the convergence precision are similar with the CPU
 and the GPU implementation.
 then his implementation on CPU (1 core). Furthermore, the number of
 iterations and the convergence precision are similar with the CPU
 and the GPU implementation.


@@ -742,9 +740,18 @@ and the GPU implementation.
  
  %We notice that the convergence precision is a round $10^{-7}$ for the both implementation on CPU and GPU. Consequently, we can conclude that Ehrlich-Aberth on GPU are faster and accurately then CPU implementation.
 
  
  %We notice that the convergence precision is a round $10^{-7}$ for the both implementation on CPU and GPU. Consequently, we can conclude that Ehrlich-Aberth on GPU are faster and accurately then CPU implementation.
 

-\subsection{Influence of the number of threads on the execution times of different polynomials (sparse and full)}
-To optimize the performances of an algorithm on a GPU, it is necessary to maximize the use of cores GPU (maximize the number of threads executed in parallel) and to optimize the use of the various memoirs GPU. In fact, it is interesting to see the influence of the number of threads per block on the execution time of Ehrlich-Aberth algorithm. 
-For that, we notice that the maximum number of threads per block for the Nvidia Tesla K40 GPU is 1024, so we varied the number of threads per block from 8 to 1024. We took into account the execution time for both sparse and full of 10 different polynomials of size 50,000 and 10 different polynomials of size 500,000 degrees.
+\subsection{Influence of the number of threads on the execution times
+  of different polynomials (sparse and full)}
+
+To optimize the performances of an algorithm on a GPU, it is necessary
+to maximize the use of the GPU cores. In fact, it is interesting to
+see the influence of the number of threads per block on the execution
+time of Ehrlich-Aberth algorithm.  For that, we notice that the
+maximum number of threads per block for the Nvidia Tesla K40 GPU is
+1024. So the number of threads per block ranges from 8 to 1024. We
+took into account the execution time for both sparse and full of 10
+different polynomials of size 50,000 and 10 different polynomials of
+size 500,000 degrees.

 
 \begin{figure}[htbp]
 \centering
 
 \begin{figure}[htbp]
 \centering


@@ -753,11 +760,17 @@ For that, we notice that the maximum number of threads per block for the Nvidia
 \label{fig:02}
 \end{figure}
 
 \label{fig:02}
 \end{figure}
 

-The figure 2 show that, the best execution time for both sparse and full polynomial are given when the threads number varies between 64 and 256 threads per bloc. We notice that with small polynomials the best number of threads per block is 64, Whereas, the large polynomials the best number of threads per block is 256. However,In the following experiments we specify that the number of thread by block is 256.
+Figure~\ref{fig:02} shows that, the best execution time for both
+sparse and full polynomial are given when the threads number varies
+between 64 and 256 threads per block. We notice that with small
+polynomials the best number of threads per block is 64, whereas the
+large polynomials the best number of threads per block is
+256. However, in the following experiments we specify that the number
+of threads per block is 256.

 
 

-\subsection{The impact of exp-log solution to compute very high degrees of  polynomial}
+\subsection{Influence of exponential-logarithm solution to compute very high degrees polynomials}

 
 

-In this experiment we report the performance of log.exp solution describe in ~\ref{sec2} to compute very high degrees polynomials.   
+In this experiment we report the performance of exp-log solution described in Section~\ref{sec2} to compute very high degrees polynomials.   

 \begin{figure}[htbp]
 \centering
   \includegraphics[width=0.8\textwidth]{figures/sparse_full_explog}
 \begin{figure}[htbp]
 \centering
   \includegraphics[width=0.8\textwidth]{figures/sparse_full_explog}


@@ -765,23 +778,42 @@ In this experiment we report the performance of log.exp solution describe in ~\r
 \label{fig:03}
 \end{figure}
 
 \label{fig:03}
 \end{figure}
 

-The figure 3, show a comparison between the execution time of the Ehrlich-Aberth algorithm applying exp.log solution and the execution time of the Ehrlich-Aberth algorithm without applying exp.log solution, with full and sparse polynomials degrees. We can see that the execution time for the both algorithms are the same while the full polynomials degrees are less than 4000 and full polynomials are less than 150,000. After,we show clearly that the classical version of Ehrlich-Aberth algorithm (without applying log.exp) stop to converge and can not solving any polynomial sparse or full. In counterpart, the new version of Ehrlich-Aberth algorithm (applying log.exp solution) can solve very high and large full polynomial exceed 100,000 degrees.
+Figure~\ref{fig:03} shows a comparison between the execution time of
+the Ehrlich-Aberth algorithm using the exp.log solution and the
+execution time of the Ehrlich-Aberth algorithm without this solution,
+with full and sparse polynomials degrees. We can see that the
+execution times for both algorithms are the same with full polynomials
+degrees less than 4000 and sparse polynomials less than 150,000. We
+also clearly show that the classical version (without log.exp) of
+Ehrlich-Aberth algorithm do not converge after these degree with
+sparse and full polynomials. In counterpart, the new version of
+Ehrlich-Aberth algorithm with the log.exp solution can solve very
+high degree polynomials.
+
+%in fact, when the modulus of the roots are up than \textit{R} given in ~\ref{R},this exceed the limited number in the mantissa of floating points representations and can not compute the iterative function given in ~\ref{eq:Aberth-H-GS} to obtain the root solution, who justify the divergence of the classical Ehrlich-Aberth algorithm. However, applying log.exp solution given in ~\ref{sec2} took into account the limit of floating using the iterative function in(Eq.~\ref{Log_H1},Eq.~\ref{Log_H2} and allows to solve a very large polynomials degrees . 

 
 

-in fact, when the modulus of the roots are up than \textit{R} given in ~\ref{R},this exceed the limited number in the mantissa of floating points representations and can not compute the iterative function given in ~\ref{eq:Aberth-H-GS} to obtain the root solution, who justify the divergence of the classical Ehrlich-Aberth algorithm. However, applying log.exp solution given in ~\ref{sec2} took into account the limit of floating using the iterative function in(Eq.~\ref{Log_H1},Eq.~\ref{Log_H2} and allows to solve a very large polynomials degrees . 

 
 
 
 

+\subsection{Comparison of the Durand-Kerner and the Ehrlich-Aberth methods}

 
 

-\subsection{A comparative study between Ehrlich-Aberth algorithm and Durand-kerner algorithm}
-In this part, we are interesting to compare the simultaneous methods, Ehrlich-Aberth and Durand-Kerner in parallel computer using GPU. We took into account the execution time, the number of iteration and the polynomial's size. for the both sparse and full polynomials.  
+In this part, we  compare the Durand-Kerner and the Ehrlich-Aberth
+methods on GPU. We took into account the execution time, the number of iteration and the polynomial's size for the both sparse and full polynomials.  

 
 \begin{figure}[htbp]
 \centering
   \includegraphics[width=0.8\textwidth]{figures/EA_DK}
 
 \begin{figure}[htbp]
 \centering
   \includegraphics[width=0.8\textwidth]{figures/EA_DK}

-\caption{The execution time of Ehrlich-Aberth versus Durand-Kerner algorithm on GPU}
+\caption{Execution times of the  Durand-Kerner and the Ehrlich-Aberth methods on GPU}

 \label{fig:04}
 \end{figure}
 
 \label{fig:04}
 \end{figure}
 

-This figure show the execution time of the both algorithm EA and DK with sparse polynomial degrees ranging from 1000 to 1000000. We can see that the Ehrlich-Aberth algorithm are faster than Durand-Kerner algorithm, with an average of 25 times as fast. Then, when degrees of polynomial exceed 500000 the execution time with EA is of the order 100 whereas DK passes in the order 1000. %with double precision not exceed $10^{-5}$.
+Figure~\ref{fig:04} shows the execution times of both methods with
+sparse polynomial degrees ranging from 1,000 to 1,000,000. We can see
+that the Ehrlich-Aberth algorithm is faster than Durand-Kerner
+algorithm, with an average of 25 times faster. Then, when degrees of
+polynomial exceed 500000 the execution time with EA is of the order
+100 whereas DK passes in the order 1000.
+
+%with double precision not exceed $10^{-5}$.

 
 \begin{figure}[htbp]
 \centering
 
 \begin{figure}[htbp]
 \centering