public documents.sextractor_doc

\chapter{Installing the software}
\section{Obtaining {\sc SExtractor}}
The easiest way to obtain {\sc SExtractor} is to \index{download} download it from the official
website\footnote{\href{http://astromatic.net/software/sextractor}{\tt
    http://astromatic.net/software/sextractor}}. 
At this address, the latest versions of the program (source code,
\index{configuration file} configuration files, and documentation) are available as standard 
{\tt .tar.gz} Unix source archives as well as RPM binary
packages for various architectures.\footnote{Mac OS X dmg files should be
 available soon.}
 
\section{Software and hardware \index{requirements} requirements}
{\sc SExtractor} has been developed on Unix machines (GNU/Linux), and should
compile on any POSIX-compliant system (this should include Mac OS X and Cygwin
under Windows, at the price of some difficulties with the configuration),
provided that the following libraries/packages have been installed:
\begin{itemize}
\item {\sc ATLAS} V3.6 and above\footnote{Use the {\tt --with-atlas} and/or
{\tt --with-atlas-incdir} options to specify the ATLAS library and include paths
if the software is installed at unusual locations.}
(\href{http://math-atlas.sourceforge.net/}{\tt http://math-atlas.sourceforge.net/})
\item {\sc FFTW} V3.0 and above\footnote{Make sure that {\sc FFTW} has been
compiled with the
{\tt configure} options {\tt --enable-threads --enable-float}).}
(\href{http://www.fftw.org/}{\tt http://www.fftw.org/})
\end{itemize}
 
Note that ATLAS and FFTw are not necessary for the binary versions of
{\sc SExtractor} which come with these libraries statically linked.
 
The software is run in (ANSI) text-mode from a shell. A graphical environment
is not necessary to operate {\sc SExtractor}.
 
Memory \index{requirements} requirements depend on the size of the \index{image} images to be processed. Processing
a single \index{image} image should typically require about 100MB of \index{memory} memory. For large
\index{image} images (hundreds of Mpixels or more), or in double-image / weighted \index{mode} mode,
{\sc SExtractor}'s \index{memory} memory footprint should be around 500MB, and up to 2GB in
the worst cases. Swap-space can be put to contribution, although a strong
performance hit is to be expected.
 
\section{Installation}
\subsection{Installation from the source archive}
To install from the source, you must first uncompress and ``untar'' the archive:
\begin{verbatim}
tar zxvf sextractor-<version>.tar.gz
\end{verbatim}
A new directory called {\tt sextractor-<version>} should now appear at the
current location on your disk. You should then enter the directory and follow
instructions given in the file called ``{\tt INSTALL}''.
 
\subsection{Installation from an RPM archive}
{\sc SExtractor} is also available as a binary RPM package for both Linux
{\sc INTEL} {\tt x86} (32-bit) and {\tt x86-64} (64-bit) architectures. To check
which one matches your system, use the shell command
\begin{verbatim}
uname -a
\end{verbatim}
To install {\sc SExtractor}, type as a root user the following command in your
shell (preceded with {\tt su} if you don't have root access but the system
administrator trusts you well enough to make you part of the {\tt wheel} group):
\begin{verbatim}
rpm -U sextractor-<version>-1.<arch>.rpm
\end{verbatim}
Under some circumstances, it may be necessary to force \index{installation} installation with
\begin{verbatim}
rpm -U --force --nodeps sextractor-<version>-1.<arch>.rpm
\end{verbatim}
You may now check that the software is properly installed by simply typing in
your shell
\begin{verbatim}
sex
\end{verbatim}
(note that some shells require the {\tt rehash} command to be run before
making a freshly installed executable accessible in the execution path).