Development/GSL

Description	Content
module load	numlib/gsl
Availability	bwUniCluster_2.0 | BwForCluster_JUSTUS_2
License	GNU General Public License (GPL)
Citing	M. Galassi et al., GNU Scientific Library Reference Manual (3rd Ed.), ISBN 0954612078.
Links	Homepage | Documentation
Graphical Interface	No

Description

The GNU Scientific Library (GSL) is a software library for numerical computations in applied mathematics and science. GSL is written in C, but bindings exist for other programming languages as well. The library provides a wide range of mathematical routines such as random number generators, special functions and least-squares fitting. There are over 1000 functions in total with an extensive test suite.

The complete range of subject areas covered by the library:

• Complex Numbers • Roots of Polynomials • Special Functions • Vectors and Matrices • Permutations • Sorting • BLAS Support • Linear Algebra • Eigensystems • Fast Fourier Transforms • Quadrature • Random Numbers • Quasi-Random Sequences • Random Distributions • Statistics • Histograms • N-Tuples • Monte Carlo Integration • Simulated Annealing • Differential Equations • Interpolation • Numerical Differentiation • Chebyshev Approximation • Series Acceleration • Discrete Hankel Transforms • Root-Finding • Minimization • Least-Squares Fitting • Physical Constants • IEEE Floating-Point • Discrete Wavelet Transforms • Basis splines • Running Statistics • Sparse Matrices and Linear Algebra

Availability

GSL is available on selected bwHPC-Clusters. A complete list of versions currently installed on the bwHPC-Clusters can be obtained from the Cluster Information System (CIS).

In order to check which versions of GSL are installed on the compute cluster, run the following command:

$ module avail numlib/gsl

Documentation

A documentation for GSL is available online.

The help page of the GSL module provides more version specific information:

$ module help numlib/gsl

----------- Module Specific Help for 'numlib/gsl/2.6' ----------
This module sets the path and environment variables for GSL-2.6.
 
 The library has been compiled with GNU compiler 8.3 using the following optimization flags:
 
  -O3 -funroll-loops -march=native -mtune=native
 
 Online-Documentation: $GSL_WWW
 
 Local-Documentation: $GSL_DOC_DIR
 
 Code Examples: $GSL_EXA_DIR
 
 Tips for compiling and linking:
 
 After having loaded the environment module, you can use several environment variables to
 compile and link your application with the GSL library.
 
 Your source code should contain preprocessor include statements with a gsl/prefix, such as
 
  #include <gsl/gsl_math.h>
 
 A typical compilation command for a source file example.c with the GNU C compiler gcc is
 
  gcc -Wall -I\$GSL_INC_DIR -c example.c
 
 The GSL_INC_DIR environment variable points to the location of the include path for the GSL header files.
 
 The following command can be used to link the application with the GSL library:
 
  gcc -L\$GSL_LIB_DIR -o example example.o -lgsl -lgslcblas -lm

 The GSL_LIB_DIR environment variable points to the location of the GSL library.
 
 In case of problems, submit a trouble ticket at 'https://bw-support.scc.kit.edu'.
 
 The full version is: numlib/gsl/2.6

Usage

Loading the module

You can load the default version of GSL with the following command:

$ module load numlib/gsl

The module will try to load all modules it needs to function (e.g., compiler, mpi, ...). If loading the module fails, check if you have already loaded one of those modules, but not in the version required by GSL.

If you wish to load another (older) version of GSL, you can do so using

$ module load numlib/gsl/<version>

with <version> specifying the desired version.

How to use GSL

A man page is available and can be accessed by typing:

$ man gsl

Includes

Your source code should contain preprocessor include statements with a gsl/prefix such as

#include <gsl/gsl_math.h>

Compile

A typical compilation command for a source file 'example.c' with the Intel C compiler icc is

 $ icc -Wall -I$GSL_INC_DIR -c example.c 

The $GSL_INC_DIR environment variable points to location of the include path for the GSL header files.

Link

The following command can be used to link the application with the GSL libraries.

 $ icc -L$GSL_LIB_DIR -o example example.o -lgsl -lgslcblas -lm 

The $GSL_LIB_DIR environment variable points to the location of the GSL libraries. Also make sure to have the GSL-module loaded before running applications build with this library.

Examples

Consider the following GSL task and create source code file 'gsl-test.c':

#include <stdio.h>
#include <gsl/gsl_sf_bessel.h>

int main (void)
{
  double x = 5.0;
  double y = gsl_sf_bessel_J0 (x);
  printf ("J0(%g) = %.18e\n", x, y);
  return 0;
}

The code can be compiled and executed with the following commands:

$ module load numlib/gsl/2.6-intel-19.1.2
$ icc -Wall -I$GSL_INC_DIR -c gsl-test.c
$ icc -L$GSL_LIB_DIR -o example gsl-test.o -lgsl -lgslcblas -lm
$ ./example
J0(5) = -1.775967713143382642e-01

Useful links

• Documentation (english)
• Wikipedia article (german)
• Wikipedia article (english)

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