How to Install ARPACK on Linux

ARPACK solves large sparse eigenvalue problems. Most distributions today package the maintained ARPACK-NG implementation, even when the binary package is still named arpack or libarpack2. Package names and repository layout differ between Debian and RHEL families, but the install intent is the same: pull the runtime library, or the development package when you compile against ARPACK.

Quick reference: ARPACK packages by distribution

Package names vary by release. Ubuntu 24.04 and newer use libarpack2t64, while older Ubuntu/Debian releases may still use libarpack2. Some Debian-family releases also provide libarpack64-2 and libarpack64-2-dev. These are ILP64 builds that use 64-bit integer interfaces; they are not ARM64-specific packages. Search your package manager before assuming the table row matches your release exactly.

What is ARPACK and ARPACK-NG?

ARPACK is a collection of Fortran routines for computing a few eigenvalues and eigenvectors of large sparse matrices. Upstream development of the original ARPACK stalled, so the community maintains ARPACK-NG as the active fork.

When you run apt install libarpack2-dev or dnf install arpack-devel, you get ARPACK-NG libraries and headers. The package names kept the older arpack wording for compatibility. On the systems tested here, both families shipped version 3.9.1.

Install ARPACK on Ubuntu and Debian

If you plan to compile software that calls ARPACK, install the development package. It pulls the runtime library automatically.

Refresh the package index first:

sudo apt update

After the package lists refresh successfully, install the development package:

sudo apt install libarpack2-dev

The install pulls libarpack2t64 as the runtime dependency. On Ubuntu 26.04 the versions looked like this:

ii  libarpack2-dev:amd64   3.9.1-6build1   amd64   Fortran77 subroutines ... (development)
ii  libarpack2t64:amd64    3.9.1-6build1   amd64   Fortran77 subroutines ...

When you only need programs that already link against ARPACK at runtime, install the runtime package alone:

sudo apt install libarpack2t64

Do not target libarpack2 on current Ubuntu or Debian unless your release still publishes that package name. On Ubuntu 26.04, libarpack2 is not the current runtime package.

To see every ARPACK-related name your release offers:

apt-cache search arpack

Sample output on Ubuntu 26.04:

libarpack2-dev - Fortran77 subroutines ... (development)
libarpack2t64 - Fortran77 subroutines to solve large scale eigenvalue problems
libparpack2-dev - Parallel subroutines ... (development)
libparpack2t64 - Parallel subroutines to solve large scale eigenvalue problems

The libarpack++2* packages are C++ bindings. This guide focuses on the standard Fortran library most scientific code expects.

Install ARPACK on RHEL, Rocky Linux, and AlmaLinux

On RHEL-family systems, ARPACK lives in EPEL, not in the base operating system repositories. Without EPEL enabled, dnf search arpack returns no matches and dnf install arpack-devel fails.

Enable EPEL

On Rocky Linux, AlmaLinux, and many rebuilds, install the EPEL release package from the default repositories:

sudo dnf install epel-release

On RHEL 10, the epel-release package may not appear in your subscribed repositories. Install the official EPEL release RPM instead:

sudo dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-10.noarch.rpm

After EPEL is enabled, dnf repolist should list a repository named epel:

epel    Extra Packages for Enterprise Linux 10 - x86_64

See install EPEL on Rocky Linux if repository setup on your host differs.

Install the ARPACK packages

For compiling against ARPACK, install the development package:

sudo dnf install arpack-devel

DNF resolves BLAS and LAPACK dependencies automatically on EL 10. A successful install on Rocky Linux 10 reported:

Installed:
  arpack-3.9.1-5.el10_0.x86_64
  arpack-devel-3.9.1-5.el10_0.x86_64
  flexiblas-3.4.2-3.el10.x86_64
  openblas-0.3.29-1.el10.x86_64

You do not need a separate FlexiBLAS workaround on RHEL 10 when EPEL is enabled. Older Rocky Linux 9 notes that required dnf --enablerepo=crb install flexiblas-devel before ARPACK do not apply as a universal EL 10 step.

When you only need runtime libraries for packaged applications:

sudo dnf install arpack

Fedora

Fedora ships arpack and arpack-devel in the primary repositories. Package names match RHEL, but you usually do not need EPEL:

sudo dnf install arpack-devel

Verify the ARPACK installation

Debian and Ubuntu

List installed ARPACK packages:

dpkg -l | grep -i arpack

Confirm the shared libraries are registered:

ldconfig -p | grep arpack

Sample output:

libarpack.so.2 (libc6,x86-64) => /usr/lib/x86_64-linux-gnu/libarpack.so.2
	libarpack.so (libc6,x86-64) => /usr/lib/x86_64-linux-gnu/libarpack.so

The development package installs headers under /usr/include/arpack/ and a pkg-config file at /usr/lib/x86_64-linux-gnu/pkgconfig/arpack.pc. The pkg-config utility is a separate package on Debian and Ubuntu:

sudo apt install pkg-config

Ask pkg-config for linker flags:

pkg-config --libs arpack

-larpack

The same metadata reports version 3.9.1 with pkg-config --modversion arpack.

RHEL, Rocky Linux, and AlmaLinux

List installed RPMs:

rpm -qa | grep -i arpack

arpack-3.9.1-5.el10_0.x86_64
arpack-devel-3.9.1-5.el10_0.x86_64

Check shared libraries:

ldconfig -p | grep arpack

libarpack64.so.2 (libc6,x86-64) => /lib64/libarpack64.so.2
	libarpack.so.2 (libc6,x86-64) => /lib64/libarpack.so.2
	libarpack.so (libc6,x86-64) => /lib64/libarpack.so

On EL systems, arpack-devel also ships arpack.pc, arpack64.pc, parpack.pc, and parpack64.pc under /usr/lib64/pkgconfig/. Query linker flags the same way:

pkg-config --libs arpack

-larpack

ARPACK runtime vs development packages

Runtime packages ship shared libraries programs load at run time. Development packages add what you need to compile and link new code.

Development packages typically provide:

• Shared library linker names such as libarpack.so
• C and Fortran headers under /usr/include/arpack/
• pkg-config .pc files and CMake config where the packager includes them

Installing only the runtime package is enough when you run software that already depends on ARPACK. Install the -dev or -devel package when you see linker errors such as cannot find -larpack or missing arpack.h.

Link a sample Fortran program

A minimal linker test confirms that the development package installed a linkable libarpack library. Save a short Fortran source file:

cat > /tmp/arpack_link.f <<'EOF'
program arpack_link_test
end program arpack_link_test
EOF

Install a Fortran compiler if you do not already have one. On Ubuntu:

sudo apt install gfortran

On RHEL-family systems, install the Fortran compiler explicitly:

sudo dnf install gcc-gfortran

Link against ARPACK. Use free-form source or start fixed-form labels in column 6; a one-line program test; end program file fails under gfortran's default fixed form:

gfortran -ffree-form -larpack -o /tmp/arpack_link_test /tmp/arpack_link.f

A silent exit with no error means the linker found libarpack. You can also pass pkg-config output directly:

gfortran -ffree-form $(pkg-config --cflags --libs arpack) -o /tmp/arpack_link_test /tmp/arpack_link.f

Install PARPACK for parallel ARPACK

PARPACK adds MPI-parallel eigenvalue routines. Skip this section unless your workload actually uses MPI.

On Ubuntu and Debian, install the parallel development package:

sudo apt install libparpack2-dev

That pulls libparpack2t64 for runtime libraries.

On RHEL 10 with EPEL enabled, there is no separate parpack RPM in repository search results. Parallel ARPACK metadata ships inside arpack-devel as parpack.pc and parpack64.pc. Install arpack-devel when you need PARPACK headers on EL systems.

Arch Linux and other distributions

On Arch-based systems, the arpack package from the official repositories includes headers, pkg-config files, and both serial and parallel libraries in one install:

sudo pacman -S arpack

Treat Arch as a short path only if you already use it. The Debian and RHEL workflows above cover the majority of server and HPC installs.

Troubleshooting

References

• ARPACK-NG project repository
• Ubuntu package: libarpack2-dev
• Debian package: libarpack2-dev
• Fedora package: arpack-devel
• EPEL package: arpack

Summary

You can install ARPACK on Linux through normal distribution packages, without building from source, on Debian and Ubuntu with libarpack2-dev and on RHEL-family systems from EPEL with arpack-devel. Current releases ship ARPACK-NG 3.9.1 even though package names still reference the older ARPACK branding.

The main pitfall on Ubuntu is the runtime rename to libarpack2t64. On RHEL, Rocky Linux, and AlmaLinux the blocker is usually a missing EPEL repository, not a manual BLAS workaround. After install, dpkg -l or rpm -qa confirms packages, ldconfig -p shows shared libraries, and pkg-config --libs arpack returns -larpack when development metadata is present.

Install libarpack2-dev or arpack-devel whenever you compile code. Reach for libparpack2-dev on Debian only when MPI parallel ARPACK is required; on EL 10 the parallel pkg-config files already ship in arpack-devel. Fedora follows the same RPM names as RHEL but typically does not need a separate EPEL step.