The LAPACK library

⚠ INFORMATION
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Description

LAPACK (Linear Algebra Package) is a library dedicated to dense linear algebra and depends on the BLAS (Basic Linear Algebra Subprograms) library. It provides functions for solving systems of linear equations, computing eigenvalues, and matrix decompositions (LU, QR, SVD, Cholesky).

LAPACK is available via the Intel MKL (Math Kernel Libraries) which we recommend because they offer better performance, or in a free version (Netlib).

Installed Versions

The versions installed on Jean Zay can be found using the following commands:

• Intel MKL Versions

  module avail intel-mkl

• Netlib Versions

  module avail netlib-lapack

Environment

The versions of LAPACK are available in different environments.

• Intel Environments

  For Intel environments, please refer to our documentation on the Intel MKL library.

• Free Version

  For the free version, this information can be found using the command module show. For example:

  module show netlib-lapack
  module-whatis    {LAPACK version 3.X is a comprehensive FORTRAN library that does linear algebra operations including matrix inversions, least squared solutions to linear sets of equations, eigenvector analysis, singular value decomposition, etc. It is a very comprehensive and reputable package that has found extensive use in the scientific community.}prereq            gcc/11.4.1 gcc/10.1.0conflict          netlib-lapack
  Available software environment(s):- gcc/11.4.1- gcc/10.1.0

To use this library in other environments, please contact the User Support team.

Note

To obtain information on the library access paths for the free version, it will be necessary to first load the chosen environment (gcc in this example):

module load gcc/11.4.1module show netlib-lapack

Usage

The library is accessible via the module command.

Using LAPACK via MKL

For using MKL, please refer to the page concerning the Intel MKL library.

Using the Free Version of LAPACK

To load the default version in the current environment (or in the default environment if no environment is previously loaded):

module load netlib-lapack

or to load a specific version in a specific environment (gcc in this example):

module load gcc/8.2.0module load netlib-lapack/3.8.0

Link Editing

Link Editing with MKL

Please refer to the page concerning the Intel MKL library.

Link editing for using MKL can vary depending on several parameters such as the operating system, compiler type, and architecture. It is recommended to use the Intel® MKL Link Line Advisor to find the appropriate options.

Here is an example for the LAPACK library:

module load intel-compilersmodule load intel-mklifort appel_lapack.f90 -L${MKLROOT}/lib/intel64 -lmkl_intel_lp64 \ 
 -lmkl_sequential -lmkl_core -lpthread -lm -ldl

Link Editing with the Free Version

When link editing, it is necessary to add the options -llapack -lblas:

module load gcc/11.4.1module load netlib-lapackgfortran appel_lapack.f90 -llapack -lblas

Documentation

📝 Reference Site
📝 Intel MKL documentation
📝 Intel MKL Link Line Advisor