Notes on using gnu Scientific Library on Athena by alexp (Alex Prengel) 
                                                                  3/12/07

The gnu Scientific Library 1.9 has been installed on Athena for Sun and
Linux. All libraries and binaries were built from source; default
Athena 9.4 gcc compilers were used (Sun: gcc version 3.4.3, Linux:
gcc version 3.4.6 20060404.

Both static and dynamic libraries have been built; however fully
static binaries are generally not possible as libc and libX11, needed
by most applications, are not available in static form on all platforms.

You will need to add the gnusl locker. Sourcing the file
/mit/gnusl/cshrc after this will set proper paths and environment 
variables for building your applications; setting the GSL_VERSION
environment variable to 1.9 before sourcing cshrc will ensure that the 
new 1.9 release is used.

The gsl-config utility, located in the gnusl_v1.9 locker (and accessible
from the gnusl locker) can be used to determine compiler and linker flags
suitable for building your applications- see the gsl-config man page
for details.

You will need to use include files in /mit/gnusl_v1.9/include in your
applications, i.e. like:

#include <gsl/gsl_spline.h>

(or whatever other includes your application requires) and link
against libraries in /mit/gnusl_v1.9/lib; generally you will need to
use libgsl and libgslblas and the system math library. To do this
you normally should have the following on your command line:

-I/mit/gnusl_v1.9/include -L/mit/gnusl_v1.9/lib -lgsl -lgslcblas -lm 

Note that you can use gsl-config output to generate this, i.e.

gcc -O2 -o myfile `gsl-config --libs --cflags` myfile.c

When you run dynamically linked binaries you build with GSL later, you
will need to point the runtime system to the dynamic libraries through
the LD_LIBRARY_PATH environment variable. This is done automatically
if you add the gnusl locker and source /mit/gnusl/cshrc (setting
GSL_VERSION if you are not using the default version), but you
probably won't want to do this every time you run something. A fairly
simple way around this is to rename your binary and use a small
"wrapper" script. If your binary is "foo", rename it to "foo.real",
and write a shell script called "foo" as follows:

#!/bin/sh
this=`dirname $0`
gnusl_default=gnusl_v1.9
if test -s /etc/athena/reactivate
then
isathena=1
attach -q gnusl
else
isathena=0
ATHENA_SYS=${ATHENA_SYS-`fs sysname | awk '{ print substr($4,2,length($4)-2)}'`}export ATHENA_SYS
attach gnusl >/dev/null
fi
if test "${GSL_VERSION-undefined}" = "undefined"
then
GSL_LOCKER=gnusl_default
else
GSL_LOCKER=gnusl_v${GSL_VERSION}
fi
if test "${LD_LIBRARY_PATH-undefined}" = "undefined"
then
LD_LIBRARY_PATH="/mit/gnusl/${GSL_LOCKER}/lib:$LD_LIBRARY_PATH"
else
LD_LIBRARY_PATH="/mit/gnusl/${GSL_LOCKER}/lib"
fi
export LD_LIBRARY_PATH
exec ${this}/foo.real "$@"

PLEASE NOTE THAT WE CAN'T GUARANTEE THAT DYNAMIC LIBRARIES WILL STAY
AROUND INDEFINITELY IN THE SAME LOCATIONS THEY ARE IN NOW! THIS MAY
BREAK DYNAMICALLY LINKED BINARIES!  You may want to copy the relevant
dynamic libraries to a location of your choosing, or use static
linking instead.

Note that the current default version of the library will be used, but this
may be overridden by setting the GSL_VERSION environment variable at run time.

Note that the script above will use the "default" version of the
library- if you require a specific version (like 1.9), you can replace
the gnusl above by a version-specific form, i.e. gnusl_v1.9.

There is much documentation available- man pages and gnu info docs in the
locker, and various READMEs in the top level directory.

Online documentation is at http://www.gnu.org/software/gsl/manual/html_node/

To view the info format docs:

add gnusl_v1.9 gnu
setenv INFOPATH /mit/gnusl_v1.9/info
info gsl-ref

man pages for gsl-config, gsl-histogram and gsl-randist are in the
gnusl_v1.9 locker.