Arpack++ with patches (C++ interface to ARPACK)
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arpackpp (ARPACK++)

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Arpackpp is a C++ interface to the ARPACK Fortran package, which implements the implicit restarted Arnoldi method for iteratively solving large-scale sparse eigenvalue problems.

Arpackpp is a collection of classes (C++ headers and examples) that offers C++ programmers an interface to ARPACK. Furthermore, it interfaces with LAPACK, SuperLU, Cholmod and UMFPACK to incorporate efficient matrix solvers. Arpackpp preserves the full capability, performance, accuracy and low memory requirements of the ARPACK Fortan package, but takes advantage of the C++ object-oriented programming environment.

This GitHub project is designed to provide a common maintained version of arpackpp. It is derived from the orignial package (ARPACK++ Version 1.2. by Gomes and Sorensen), which has not been actively maintained for many years. Several updates have been included in this version (some of them were previously hosted as patches at ). This GitHub repository is designed to collect fixes and updates (e.g. to more recent or future releases of the involved libraries). Please consider contributing (see todo list below).


Features of original ARPACK++ package:

  • Friendly interface that hides the complicated reverese communication interface of the Fortran Arpack package from the user.

  • Easy interface using matrices and vectors via the Standard Template Library (STL).

  • Provides an interface between ARPACK and solvers in SuperLU, LAPACK, UMFPACK, and CHOLMOD to solve eigenvalue problems (specifically shift invert methods).

  • Use of templates for optimal performance.

Additional features of this GitHub arpackpp package:


  • CMake: get rid of globbing and specify individual files, also add some testing
  • UMFPACK complex examples do not build (need update like sym)
  • CHOLMOD complex examples not included (implement similar to real sym)
  • Update documentation (install) to cover more scenarios (APT, Homebrew)


  1. Files included in the main directory:


    This file.


    Compile and install notes.

  4. (historic):

    An include file used to compile arpackpp examples. You must change some directories and machine-dependent directives contained into this file prior to compiling the examples. See the description of the "makefiles" directory below.

  5. CmakeLists.txt:

    A Cmake file to compile arpackpp examples.

  6. install-*.sh

    Shell scripts to download and install dependencies into a local ./external directory. Some dependencies can also be installed via a package-manager on your system.

  7. arpackpp subdirectories:

  8. makefiles (historic)

    This directory contains example include files for some platforms. Choose one and copy it onto the arpackpp/ file.

  9. include:

    The directory that contains arpackpp library, i.e., all header files that define arpackpp class templates.

  10. examples:

    The directory where all arpackpp examples can be found. These examples are intended to illustrate how to use and compile arpackpp classes and are divided according to the type of problem being solved and also the kind of information that the user is supposed to supply. Look at the examples/README file for further information.

    Note: additional header files are contained in examples/matrices and examples/matprod that are needed to build examples or your own code!

  11. doc:

    The directory that contains a the arpackpp user's manual and some instructions on how to install the libraries required by arpackpp.


For specific operations only, any of these:

  1. ARPACK (fortran):

    Arpackpp is a C++ interface to ARPACK fortran code, so the original ARPACK library must be installed prior to using the C++ version. A mainted package (arpack new generation) can be obtained via this GitHub repository (see also

  2. BLAS and LAPACK (fortran versions):

    BLAS and LAPACK routines required by ARPACK fortran code are distributed along with the software. However, some arpackpp examples require routines from these libraries that are not included in the ARPACK distribution, so it is recommended to install BLAS and LAPACK before compiling the examples. Besides, you should use vendor-optimized versions of these libraries if they are available. E.g. OpenBLAS is available via this GitHub repository (see also


    Some ARPACK++ classes call SUPERLU library functions to solve eigenvalue problems that require complex or real (non)symmetric matrix decompositions. Thus, SUPERLU must also be installed if you intend to use one of these classes. SUPERLU is available at this webpage (see also


    UMFPACK package can also be used to solve eigenvalue problems that require real or complex (non)symmetric/non-Hermitian matrix decompositions. UMFPACK is now part of the SuiteSparse package which can be obtained here (see also


    CHOLMOD package is performing a Cholesky decomposition. Some of the symmetric problems can now interface with it. It is part of the SuiteSparse package which can be obtained here (see also


Arpackpp user's manual is available in the doc directory. It contains all information needed to declare and solve eigenvalue problems using arpack++ classes and functions. Arpackpp computational modes and data types are also described in the manual. Instructions on how to install the above mentioned libraries are given in the file. Moreover, README files were include in many arpackpp directories to give additional information about arpackpp files and examples.

Using arpackpp:

As a collection of class templates, arpackpp need not to be compiled. Because templates are defined in header (.h) files, no object (.o) or library (.a) files have to be build, except those corresponding to other libraries required by arpackpp (see Dependencies above). Arpackpp header files are included in the "include" directory and can be moved to another directory if desired. An option in the form

-I$(ARPACKPP_INC)/../examples/matrices \

should be added to the command line when compiling programs that use arpackpp. Here, ARPACKPP_INC is the name of the directory that contains all arpackpp header files. Note, depending on what type of problem you want so solve, you need to also include the example matrices and/or matprod directories (see examples). You can also use cmake (see below) with make install to install all headers to your system into a single directory.

Compiling and running arpackpp examples:

Arpackpp supports cmake for the compilation of the examples. To build all examples, including the ones that depend on SuperLU, do

$ mkdir ../arpackpp-build
$ cd ../arpackpp-build
$ cmake ../arpackpp -D SUPERLU=ON
$ make examples

For this to work all dependencies need to be installed (either on the system or in the external subdirectory). See for details. Regular Makefiles (in-source build) are also still supported.


ARPACK++ authors:

  • Francisco M. Gomes (chico AT

  • Danny Sorensen (LASTNAME AT

arpackpp (2.0.0 and above) authors:

  • Martin Reuter (LASTNAME AT