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\leaf{PiFast : the fastest windows program to compute pi}
\begin{center}
\small
\htmlred{(128 million digits of $\pi$ in less than 15 minutes on your computer !)}
\end{center}
{\large \htmlgreen{Records with pifast :}}
\htmlgreen{
\begin{itemize}
\item pi with 25 billion digits (Size world record pi computation
  on a home computer)
\item $e$ with 50.1 billion digits ($e$ size world record computation)
\item One billion digits of pi in less than 3 hours 48 minutes.
\item One billion digits of $e$ in 1 hour 31 minutes.
\end{itemize}
}

{\em PiFast} is an easy-to-use package written by Xavier
Gourdon to compute $\pi$
with a very large number of digits. PiFast is avalaible on several 
platforms, download it from~\href{download.html}{here}.
PiFast can also compute $E$ and a large family of user defined constants.

\subsection*{PiFast features}

\begin{itemize}
\item Computes decimal digits of pi, e=exp(1), sqrt2, with the high
  limit of 17 billion digits.
\item Very fast (fastest pi program available on the web - July 5
  2003).
\item Much more economical in memory than other pi programs.
\item Parameters can be used to fit in the memory machine (memory saved
  <-> time lost).
\item Able to handle  disk memory for very large computations,
  permitting to compute much more digits than could be contained in
  the physical memory.
\item Very large computations can be done in several chunks.
\item Can compute a lot of other predefined constants (log(2),
  zeta(3), ...) with many formulas.
\item User can define his own formula to compute a constant.
\item Can compress directly the output result and later, decompress
  all or part of it.
\end{itemize}

\subsection*{Current version : Version 4.3}

Version 4.3 is released (July 2003). This version is slightly faster
than the previous version. Contains bug corrections; 
theoritical limit size has increased from 12 Gigas to 16 Gigas decimal
digits. More features and informations on pifast can be found in
the {\tt doc.txt} file on the \href{download.html}{downlad page}.


\subsection*{Other Pi programs on the web}

Other pi programs on the web are referenced and compared on 
\hreftop{http://home.istar.ca/~lyster/pi.html}{Stu's pi page}.
Among those, two programs are 
comparable in speed with PiFast :
The program QuickPi, from Steve Pagliarulo, is comparable in speed
with PiFast when the number of digits is less than 1 million but
becomes less efficient for larger computations.
Another pi program running on Linux, named Schnell-pi and written by
Dominique Delande is also comparable in speed with pifast. 
No windows version of this program exists for the moment.

\iftth
\hrule
\label{links}
\begin{center}
{\Large\bf\em Related links on $\pi$ programs and computations}
\end{center}
\begin{itemize}
\item
\hreftop{http://home.istar.ca/~lyster/pi.html}{Stu's pi page} A best pi
programs record site.
\item
\hreftop{http://www.myownlittleworld.com/pi/pitable.html}{Dara's Pi pages}
Pi programs and comparison on several architectures.
\item 
\hreftop{http://www.mdb.gr.jp/ja0hxv/}{Shigeru Kondo pi pages} 
The home page of the holder of most of the $\pi$ and $e$ records on a
home computer.
\item
\hreftop{http://www.lesfurieux.net/}{Home page of overclockers} (in
french). Summarizes the best timings obtained with various
benchmark programs, including pifast for 50 million digits and 1
billion digits.
\end{itemize}
\fi

\hrule 

\label{contact}
\section*{Contact}
For any general comments or large number of digits computation
experience with {\tt PiFast}, send a message to 
\href{mailto:xgourdon@yahoo.fr}{xgourdon@yahoo.fr}.


\iftth
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\htmlgreen{\bf Back to} \hreftop{../constants.html}{numbers, constants and computation}
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