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
  Wavelets

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.

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 (see 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/).

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.  Precompiled versions of the library can be purchased from commercial redistributors listed on the website above.

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.

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 for further details (see GNU General Public License).

Reporting Bugs
==============

A list of known bugs can be found in the BUGS file included in the GSL distribution.  Details of compilation problems can be found in the 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.

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 (2nd Ed.), ISBN 0954161734.

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

Conventions used in this manual
===============================

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 (bash).