.. index::

   license of GSL

   GNU General Public License

************

Introduction

************

The GNU Scientific Library (GSL) is a collection of routines for

numerical computing.  The routines have been written from scratch in C,

and present a modern Applications Programming Interface

(API) for C programmers, allowing wrappers to be written for very

high level languages.  The source code is distributed under the GNU

General Public License.

Routines available in GSL

=========================

The library covers a wide range of topics in numerical computing.

Routines are available for the following areas,

===========================  ===========================  ===========================

Complex Numbers              Roots of Polynomials         Special Functions

Vectors and Matrices         Permutations                 Combinations

Sorting                      BLAS Support                 Linear Algebra

CBLAS Library                Fast Fourier Transforms      Eigensystems

Random Numbers               Quadrature                   Random Distributions

Quasi-Random Sequences       Histograms                   Statistics

Monte Carlo Integration      N-Tuples                     Differential Equations

Simulated Annealing          Numerical Differentiation    Interpolation

Series Acceleration          Chebyshev Approximations     Root-Finding

Discrete Hankel Transforms   Least-Squares Fitting        Minimization

IEEE Floating-Point          Physical Constants           Basis Splines

Wavelets                     Sparse BLAS Support          Sparse Linear Algebra

===========================  ===========================  ===========================

The use of these routines is described in this manual.  Each chapter

provides detailed definitions of the functions, followed by example

programs and references to the articles on which the algorithms are

based.

Where possible the routines have been based on reliable public-domain

packages such as FFTPACK and QUADPACK, which the developers of GSL

have reimplemented in C with modern coding conventions.

.. index::

   single: free software, explanation of

GSL is Free Software

====================

The subroutines in the GNU Scientific Library are "free software";

this means that everyone is free to use them, and to redistribute them

in other free programs.  The library is not in the public domain; it is

copyrighted and there are conditions on its distribution.  These

conditions are designed to permit everything that a good cooperating

citizen would want to do.  What is not allowed is to try to prevent

others from further sharing any version of the software that they might

get from you.

Specifically, we want to make sure that you have the right to share

copies of programs that you are given which use the GNU Scientific

Library, that you receive their source code or else can get it if you

want it, that you can change these programs or use pieces of them in new

free programs, and that you know you can do these things.

To make sure that everyone has such rights, we have to forbid you to

deprive anyone else of these rights.  For example, if you distribute

copies of any code which uses the GNU Scientific Library, you must give

the recipients all the rights that you have received.  You must make

sure that they, too, receive or can get the source code, both to the

library and the code which uses it.  And you must tell them their

rights.  This means that the library should not be redistributed in

proprietary programs.

Also, for our own protection, we must make certain that everyone finds

out that there is no warranty for the GNU Scientific Library.  If these

programs are modified by someone else and passed on, we want their

recipients to know that what they have is not what we distributed, so

that any problems introduced by others will not reflect on our

reputation.

The precise conditions for the distribution of software related to the

GNU Scientific Library are found in the

`GNU General Public License <https://www.gnu.org/software/gsl/manual/html_node/GNU-General-Public-License.html#GNU-General-Public-License>`_.

Further information about this

license is available from the GNU Project webpage `Frequently Asked

Questions about the GNU GPL <http://www.gnu.org/copyleft/gpl-faq.html>`_.

The Free Software Foundation also operates a license consulting

service for commercial users (contact details available from

http://www.fsf.org.

.. index::

   obtaining GSL

   downloading GSL

   mailing list for GSL announcements

   info-gsl mailing list

Obtaining GSL

=============

The source code for the library can be obtained in different ways, by

copying it from a friend, purchasing it on CDROM or downloading it

from the internet. A list of public ftp servers which carry the source

code can be found on the GNU website, http://www.gnu.org/software/gsl/.

The preferred platform for the library is a GNU system, which allows it

to take advantage of additional features in the GNU C compiler and GNU C

library.  However, the library is fully portable and should compile on

most systems with a C compiler. 

Announcements of new releases, updates and other relevant events are

made on the info-gsl@gnu.org mailing list.  To subscribe to this

low-volume list, send an email of the following form::

    To: info-gsl-request@gnu.org 

    Subject: subscribe

You will receive a response asking you to reply in order to confirm

your subscription.

.. index::

   warranty (none)

No Warranty

===========

The software described in this manual has no warranty, it is provided

"as is".  It is your responsibility to validate the behavior of the

routines and their accuracy using the source code provided, or to

purchase support and warranties from commercial redistributors.  Consult the

`GNU General Public License <https://www.gnu.org/software/gsl/manual/html_node/GNU-General-Public-License.html#GNU-General-Public-License>`_

for further details.

.. index::

   reporting bugs in GSL

   bugs, how to report

   bug-gsl mailing list

   mailing list, bug-gsl

Reporting Bugs

==============

A list of known bugs can be found in the :file:`BUGS` file included in

the GSL distribution or online in the GSL bug tracker. [#f1]_

Details of compilation problems can be found in the :file:`INSTALL` file.

If you find a bug which is not listed in these files, please report it to

bug-gsl@gnu.org.

All bug reports should include:

- The version number of GSL

- The hardware and operating system

- The compiler used, including version number and compilation options

- A description of the bug behavior

- A short program which exercises the bug

It is useful if you can check whether the same problem occurs when the

library is compiled without optimization.  Thank you.

Any errors or omissions in this manual can also be reported to the

same address.

.. index::

   mailing list archives

   single: website, developer information

   contacting the GSL developers

Further Information

===================

Additional information, including online copies of this manual, links to

related projects, and mailing list archives are available from the

website mentioned above.  

Any questions about the use and installation of the library can be asked

on the mailing list help-gsl@gnu.org.  To subscribe to this

list, send an email of the following form::

    To: help-gsl-request@gnu.org

    Subject: subscribe

This mailing list can be used to ask questions not covered by this

manual, and to contact the developers of the library.

If you would like to refer to the GNU Scientific Library in a journal

article, the recommended way is to cite this reference manual,

e.g.::

    M. Galassi et al, GNU Scientific Library Reference Manual (3rd Ed.), ISBN 0954612078.

If you want to give a url, use "http://www.gnu.org/software/gsl/".

.. index::

   single: conventions, used in manual

   single: examples, conventions used in

   single: shell prompt

   single: $, shell prompt

Conventions used in this manual

===============================

.. index::

   single: dollar sign $, shell prompt

This manual contains many examples which can be typed at the keyboard.

A command entered at the terminal is shown like this::

    $ command

The first character on the line is the terminal prompt, and should not

be typed.  The dollar sign $ is used as the standard prompt in

this manual, although some systems may use a different character.

The examples assume the use of the GNU operating system.  There may be

minor differences in the output on other systems.  The commands for

setting environment variables use the Bourne shell syntax of the

standard GNU shell (:code:`bash`).

.. rubric:: Footnotes

.. [#f1] http://savannah.gnu.org/bugs/?group=gsl