For using the igraph C library
This chapter describes building igraph from source code and installing it. The source archive of the latest stable release is always available from the igraph website. igraph is also included in many Linux distributions, as well as several package managers such as vcpkg (convenient on Windows), MacPorts (macOS) and Homebrew (macOS), which provide an easier means of installation. If you decide to use them, please consult their documentation on how to install packages.
To build igraph from sources, you will need at least:
CMake 3.18 or later
C and C++ compilers
Visual Studio 2015 and later are supported. Earlier Visual Studio versions may or may not work.
Certain features also require the following libraries:
libxml2, required for GraphML support
igraph bundles a number of libraries for convenience. However, it is preferable to use external versions of these libraries, which may improve performance. These are:
When building the development version of igraph,
git are also required. Released versions do not
require these tools.
To run the tests,
diff is also required.
igraph uses a CMake-based build system. To compile it,
Enter the directory where the igraph sources are:
$ cd igraph
Create a new directory. This is where igraph will be built:
$ mkdir build $ cd build
Run CMake, which will automatically configure igraph, and report the configuration:
$ cmake ..
To set a non-default installation location, such as
cmake .. -DCMAKE_INSTALL_PREFIX=/opt/local
Check the output carefully, and ensure that all features you need are enabled. If CMake could not find certain libraries, some features such as GraphML support may have been automatically disabled.
There are several ways to adjust the configuration:
ccmake . on Unix-like systems or
cmake-gui on Windows for a convenient
Simply edit the
Some of the relevant options are listed below.
Once the configuration has been adjusted, run
cmake .. again.
Once igraph has been successfully configured, it can be built, tested and installed using:
$ cmake --build . $ cmake --build . --target check $ cmake --install .
With Visual Studio, the steps to build igraph are generally the
same as above. However, since the Visual Studio CMake generator is
a multi-configuration one, we must specify the configuration
(typically Release or Debug) with each build command using the
mkdir build cd build cmake .. cmake --build . --config Release cmake --build . --target check --config Release
When building the development version,
flex must be available on the system.
for Bison version 3.x can be useful for this purpose—make sure
that the executables are in the system
The easiest installation option is probably by installing
winflexbison3 from the
Most external dependencies can be conveniently installed using
igraph bundles all dependencies
libxml2, which is needed for GraphML
In order to use vcpkg integrate it in the build environment by executing
vcpkg.exe integrate install on the command line.
When configuring igraph, point CMake to the correct
vcpkg.cmake file using
Additionally, it might be that you need to set the appropriate
so-called triplet using
-DVCPKG_TARGET_TRIPLET when running
cmake, for exampling, setting it to
x64-windows when using shared builds of packages or
x64-windows-static when using static builds.
Similarly, you also need to specify this target triplet when
installing packages. For example, to install
libxml2 as a shared library, use
vcpkg.exe install libxml2:x64-windows and to
libxml2 as a static library, use
vcpkg.exe install libxml2:x64-windows-static.
In addition, there is the possibility to use a static library
with dynamic runtime linking using the
MSYS2 can be installed from msys2.org. After installing MSYS2,
ensure that it is up to date by opening a terminal and running
The instructions below assume that you want to compile for a 64-bit target.
Install the following packages using
Optional dependencies that enable certain features:
Optional external libraries for better performance:
Only needed for running the tests:
Required only when building the development version:
The following command will install of these at once:
pacman -S \ mingw-w64-x86_64-toolchain mingw-w64-x86_64-cmake \ mingw-w64-x86_64-gmp mingw-w64-x86_64-libxml2 \ mingw-w64-x86_64-openblas mingw-w64-x86_64-arpack \ mingw-w64-x86_64-glpk diffutils git bison flex
In order to build igraph, follow the General build instructions above, paying attention to the following:
When using MSYS2, start the “MSYS2 MinGW 64-bit” terminal, and not the “MSYS2 MSYS” one.
Be sure to install the
package and not the
cmake one. The latter
will not work.
cmake, pass the option
ccmake is not currently available.
cmake-gui can be used only if the
mingw-w64-x86_64-qt5 package is installed.
The following options may be set to
OFF. Some of them have an
setting, which chooses a reasonable default based on what libraries
are available on the current system.
igraph bundles some of its dependencies for convenience. The
IGRAPH_USE_INTERNAL_XXX flags control whether
these should be used instead of external versions. Set them to
ON to use the bundled
(“vendored”) versions. Generally, external versions
are preferable as they may be newer and usually provide better
IGRAPH_GLPK_SUPPORT: whether to make use of
library. Some features, such as finding a minimum feedback arc
set or finding communities through exact modularity
optimization, require this.
IGRAPH_OPENMP_SUPPORT: whether to use OpenMP
parallelization to accelerate certain functions such as PageRank
calculation. Compiler support is required.
IGRAPH_ENABLE_LTO: whether to build igraph
with link-time optimization, which improves performance. Not
supported with all compilers.
IGRAPH_ENABLE_TLS: whether to enable
thread-local storage. Required when using igraph from multiple
IGRAPH_WARNINGS_AS_ERRORS: whether to treat
compiler warnings as errors. We strive to eliminate all compiler
warnings during development so this switch is turned on by default.
If your compiler prints warnings for some parts of the code that we
did not anticipate, you can turn off this option to prevent the
warnings from stopping the compilation.
whether to build a shared library instead of a static one.
the location where igraph will be installed.
Most users will not need to build the documentation, as the release
tarball contains pre-built HTML documentation in the
To build the documentation for the development version, simply build
$ cmake --build . --target html
Building the HTML documentation requires Python 3,
source-highlight. Building the PDF documentation
This section is for people who package igraph for Linux distros or other package managers. Please read it carefully before packaging igraph.
igraph bundles several of its dependencies (or simplified versions
of its dependencies). During configuration time, it checks whether
each dependency is present on the system. If yes, it uses it.
Otherwise, it falls back to the bundled (“vendored”)
version. In order to make configuration as deterministic as
possible, you may want to disable this auto-detection. To do so, set
each of the
described above. Additionally, set
use the BLAS and LAPACK implementations of your choice. This should
be the same BLAS and LAPACK library that igraph's other dependencies
(e.g., ARPACK) are linked against.
For example, to force igraph to use external versions of all dependencies, and to use OpenBLAS for BLAS/LAPACK, use
$ cmake .. \ -DIGRAPH_USE_INTERNAL_BLAS=OFF \ -DIGRAPH_USE_INTERNAL_LAPACK=OFF \ -DIGRAPH_USE_INTERNAL_ARPACK=OFF \ -DIGRAPH_USE_INTERNAL_GLPK=OFF \ -DIGRAPH_USE_INTERNAL_GMP=OFF \ -DBLA_VENDOR=OpenBLAS \ -DIGRAPH_GRAPHML_SUPPORT=ON
On Windows, shared and static builds should not be installed in the same
location. If you decide to do so anyway, keep in mind the following:
Both builds contain an
igraph.lib file. The static one
should be renamed to avoid conflict. The headers from the static build
are incompatible with the shared library. The headers from the shared build
may be used with the static library, but
must be defined when compiling programs that will link to igraph statically.
These issues do not affect Unix-like systems.
When building igraph with an internal ARPACK, LAPACK or BLAS, it
makes use of f2c, which compiles and runs the
program at build time to detect the floating point characteristics of the
current system. It writes the results into the
header. However, running this program is not possible when cross-compiling
without providing a userspace emulator that can run executables of the
target platform on the host system. Therefore, when cross-compiling, you
either need to provide such an emulator with the
CMAKE_CROSSCOMPILING_EMULATOR option, or you need to
specify a pre-generated version of the
file through the
CMake option. An example version of this header follows for the
x86_64 and arm64 target architecures on macOS. Warning: Do not use this
arith.h on other systems or architectures.
#define IEEE_8087 #define Arith_Kind_ASL 1 #define Long int #define Intcast (int)(long) #define Double_Align #define X64_bit_pointers #define NANCHECK #define QNaN0 0x0 #define QNaN1 0x7ff80000
igraph also checks whether the endianness of
matches the endianness of
double on the platform
being compiled. This is needed to ensure that certain functions in igraph's
random number generator work properly. However, it is not possible to
execute this check when cross-compiling without an emulator, so in this
case igraph simply assumes that the endianness matches (which is the case
for the vast majority of platforms anyway). The only case where you might
run into problems is when you cross-compile for Apple Silicon
arm64) from an Intel-based Mac, in which case CMake
might not realize that you are cross-compiling and will try to execute
the check anyway. You can work around this by setting
explicitly before invoking CMake.
Providing an emulator in
has the added benefit that you can run the compiled unit tests on the
host platform. We have experimented with cross-compiling to 64-bit ARM
aarch64) on 64-bit Intel CPUs (
and we can confirm that using
qemu-aarch64 works as a
cross-compiling emulator in this setup.
As of igraph 0.10, there is no tangible benefit to using an external GMP, as igraph does not yet use GMP in any performance-critical way. The bundled Mini-GMP is sufficient.
Link-time optimization noticeably improves the performance of
some igraph functions. To enable it, use
AUTO setting is also supported, and will
enable link-time optimization only if the current compiler
supports it. Note that this is detected by CMake, and the
detection is not always accurate.
We saw occasional hangs on Windows when igraph was built for a 32-bit target with MinGW and linked to OpenBLAS. We believe this to be an issue with OpenBLAS, not igraph. On this platform, you may want to opt for a different BLAS/LAPACK or the bundled BLAS/LAPACK.
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