X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/kahina_paper1.git/blobdiff_plain/2012ce2acb409df5a2db763463252497a2f32663..12b2d99947e482e179e6954270d38c8b632a4f8e:/paper.tex diff --git a/paper.tex b/paper.tex index 96e01fd..2dcee57 100644 --- a/paper.tex +++ b/paper.tex @@ -345,14 +345,12 @@ propose to use the logarithm and the exponential of a complex in order to comput Using the logarithm (eq.~\ref{deflncomplex}) and the exponential (eq.~\ref{defexpcomplex}) operators, we can replace any multiplications and divisions with additions and subtractions. Consequently, computations manipulate lower absolute values and the roots for large polynomial's degrees can be looked for successfully~\cite{Karimall98}. -Applying this solution for the Ehrlich-Aberth method we obtain the -iteration function with exponential and logarithm: +Applying this solution for the iteration function Eq.~\ref{Eq:Hi} of Ehrlich-Aberth method, we obtain the iteration function with exponential and logarithm: %%$$ \exp \bigl( \ln(p(z)_{k})-ln(\ln(p(z)_{k}^{'}))- \ln(1- \exp(\ln(p(z)_{k})-ln(\ln(p(z)_{k}^{'})+\ln\sum_{i\neq j}^{n}\frac{1}{z_{k}-z_{j}})$$ \begin{equation} \label{Log_H2} EA.EL: z^{k+1}_{i}=z_{i}^{k}-\exp \left(\ln \left( -p(z_{i}^{k})\right)-\ln\left(p'(z^{k}_{i})\right)- \ln -\left(1-Q(z^{k}_{i})\right)\right), +p(z_{i}^{k})\right)-\ln\left(p'(z^{k}_{i})\right)- \ln\left(1-Q(z^{k}_{i})\right)\right), \end{equation} where: @@ -366,7 +364,7 @@ Q(z^{k}_{i})=\exp\left( \ln (p(z^{k}_{i}))-\ln(p'(z^{k}_{i}))+\ln \left( This solution is applied when the root except the circle unit, represented by the radius $R$ evaluated in C language as : \begin{equation} \label{R.EL} -R = exp(log(DBL_MAX)/(2*n) ); +R = exp(log(DBL\_MAX)/(2*n) ); \end{equation} @@ -409,7 +407,7 @@ other processors at the end of each iteration (synchronous). Therefore they cause a high degree of memory conflict. Recently the author in~\cite{Mirankar71} proposed two versions of parallel algorithm for the Durand-Kerner method, and Ehrlich-Aberth method on a model of -Optoelectronic Transpose Interconnection System (OTIS).The +Optoelectronic Transpose Interconnection System (OTIS). The algorithms are mapped on an OTIS-2D torus using $N$ processors. This solution needs $N$ processors to compute $N$ roots, which is not practical for solving polynomials with large degrees. @@ -542,7 +540,7 @@ polynomials of 48,000. \subsection{Parallel implementation with CUDA } In order to implement the Ehrlich-Aberth method in CUDA, it is -possible to use the Jacobi scheme or the Gauss Seidel one. With the +possible to use the Jacobi scheme or the Gauss-Seidel one. With the Jacobi iteration, at iteration $k+1$ we need all the previous values $z^{k}_{i}$ to compute the new values $z^{k+1}_{i}$, that is : @@ -560,7 +558,7 @@ With the Gauss-Seidel iteration, we have: \begin{equation} \label{eq:Aberth-H-GS} EAGS: z^{k+1}_{i}=z_{i}^{k}-\frac{\frac{p(z_{i}^{k})}{p'(z_{i}^{k})}} -{1-\frac{p(z_{i}^{k})}{p'(z_{i}^{k})}(\sum^{i-1}_{j=1}\frac{1}{z^{k}_{i}-z^{k+1}_{j}}+\sum_{j=1,j\neq i}^{j=n}{\frac{1}{(z_{i}^{k}-z_{j}^{k})}})}, i=1,. . . .,n +{1-\frac{p(z_{i}^{k})}{p'(z_{i}^{k})}(\sum^{i-1}_{j=1}\frac{1}{z^{k}_{i}-z^{k+1}_{j}}+\sum_{j=i+1}^{j=n}{\frac{1}{(z_{i}^{k}-z_{j}^{k})}})}, i=1,. . . .,n \end{equation} Using Eq.~\ref{eq:Aberth-H-GS} to update the vector solution @@ -582,7 +580,7 @@ quickly because, just as any Jacobi algorithm (for solving linear systems of equ %In CUDA programming, all the instructions of the \verb=for= loop are executed by the GPU as a kernel. A kernel is a function written in CUDA and defined by the \verb=__global__= qualifier added before a usual \verb=C= function, which instructs the compiler to generate appropriate code to pass it to the CUDA runtime in order to be executed on the GPU. -Algorithm~\ref{alg2-cuda} shows sketch of the Ehrlich-Aberth algorithm using CUDA. +Algorithm~\ref{alg2-cuda} shows sketch of the Ehrlich-Aberth method using CUDA. \begin{enumerate} \begin{algorithm}[H] @@ -590,7 +588,7 @@ Algorithm~\ref{alg2-cuda} shows sketch of the Ehrlich-Aberth algorithm using CUD %\LinesNumbered \caption{CUDA Algorithm to find roots with the Ehrlich-Aberth method} -\KwIn{$Z^{0}$ (Initial root's vector), $\varepsilon$ (error tolerance +\KwIn{$Z^{0}$ (Initial root's vector), $\varepsilon$ (Error tolerance threshold), P (Polynomial to solve), Pu (Derivative of P), $n$ (Polynomial's degrees), $\Delta z_{max}$ (Maximum value of stop condition)} \KwOut {$Z$ (Solution root's vector), $ZPrec$ (Previous solution root's vector)}