This page describes how to build FEAT3 with thirdparty dependencies using FEATs CMake build system. The main text will walk you through using the configure script to enable and manage thirdparty dependencies. Throughout the text are note sections. These contain additional information about the inner working of the CMake build system for experienced CMake users. If you only plan on using the configure script, you can safely skip these.

Reference

Reference table of supported thirdparty dependencies:

Dependency	Build-id tag	CMake flag	<TPL>_DIR	Link	Notes
Alglib	alglib	FEAT_HAVE_ALGLIB	Alglib_DIR	https://www.alglib.net/
Boost	boost	FEAT_HAVE_BOOST	Boost_DIR	https://www.boost.org/
CGAL	cgal	FEAT_HAVE_CGAL	CGAL_DIR	https://www.cgal.org/
cuDSS	cudss	FEAT_HAVE_CUDSS	cudss_DIR	https://developer.nvidia.com/cudss
deathhandler	deathhandler	FEAT_HAVE_DEATHHANDLER	death_handler_DIR	https://github.com/vmarkovtsev/DeathHandler
fparser	fparser	FEAT_HAVE_FPARSER	fparser_DIR	http://warp.povusers.org/FunctionParser/
floatx	floatx	FEAT_HAVE_FLOATX	FloatX_DIR	https://github.com/oprecomp/FloatX
hypre	hypre	FEAT_HAVE_HYPRE	HYPRE_DIR	https://github.com/hypre-space/hypre
ParMETIS	metis	FEAT_HAVE_PARMETIS	parmetis_DIR	https://github.com/KarypisLab/ParMETIS
SuperLU (dist)	superlu	FEAT_HAVE_SUPERLU_DIST	superlu_DIR	https://github.com/xiaoyeli/superlu_dist
Triangle	triangle	FEAT_HAVE_TRIANGLE	triangle_DIR	https://github.com/libigl/triangle
UMFPACK	umfpack	FEAT_HAVE_UMFPACK	UMFPACK_DIR	https://github.com/DrTimothyAldenDavis/SuiteSparse	Must be built with MKL, if FEAT uses MKL
zlib	zlib	FEAT_HAVE_ZLIB	zlib_DIR	https://zlib.net/
Zoltan	zoltan	FEAT_HAVE_ZOLTAN	zoltan_DIR	https://sandialabs.github.io/Zoltan/
zfp	zfp	FEAT_HAVE_ZFP	zfp_DIR	https://github.com/LLNL/zfp
PMP	pmp	FEAT_HAVE_PMP	pmp_DIR	https://www.pmp-library.org/

Enabling thirdparty dependencies

This document assumes that you are familiar with basic usage of the FEAT3 configure script such as producing debug and release builds with different compilers. You can enable additional features, such as MPI support, the UMFPACK solver, or data compression via zlib, by adding additional tags to the build-id you pass to the configure script. As an example, to build FEAT3 with the UMFPACK solver you can configure it as

/path/to/configure gcc-opt-umfpack

to receive a build system that will build FEAT3 with the GCC C++ compiler, with optimizations and the UMFPACK solver. Certain thirdparty dependencies depend on each other. The ParMETIS partitioner for example, requires you to also enable MPI. The configure script will warn you in these cases.

Note: Internally dependencies are tracked using a set of flags in the CMake cache. These flags are named FEAT_HAVE_<TPL>. If you already have a configured build directory, you can also add or disable thirdparty dependencies by toggling these flags in the CMake cache and then reconfiguring your build system.

Resolving thirdparty dependencies

The CMake build system will do its best to fulfill the third party dependencies you requested. By default dependencies are first searched for among the libraries installed on the system. If a dependency can not be fulfilled that way, CMake will download the dependency itself and include it in the FEAT3 build.

Finding thirdparty dependencies

CMake will search for thirdparty dependencies in the usual install directories.

Note: FEAT relies on the CMake packages exported by thirdparty dependencies, if possible. FEAT ships with custom FindModules For any thirdparty dependency that does not produce a CMake package on installation.

You can specify an additional directory that FEAT will consider if searching for thirdparty dependencies. To do so, pass the directory to the configure script using the --package_install_dir option.

path/to/configure gcc-opt-umfpack --package_install_dir=path/to/umfpack

Note: The --package_install_dir option sets the given path as the CMAKE_INSTALL_PREFIX .

If you do not want CMake to search among the installed libraries, and instead want it to download all dependencies itself, you can pass the –no_external_libs flag to the configure script. Doing so will stop CMake from searching for installed libraries.

path/to/configure gcc-opt-umfpack --no_external_libs

Note: The --no_external_libs flag sets the CMake flag FEAT_PREFER_EXTERNAL_TPL to OFF

If you want CMake to only use the locally installed versions of some libraries, but download all others, you can first disable searching for any thirdparty library using the --no_external_libs flag of the configure script. You can then manually set the directories of all thirdparty dependencies that you do not want CMake to download. To do so, you have to set the corresponding <TPL>_DIR variables (see the <TPL>_DIR column of the table above). The configure script provides a way to fill the CMake cache with an initial set of values, allowing you to set these variables without having to configure a build system beforehand. First create a CMake script that sets up the initial cache. For example:

cat > initial-cache.cmake <<EOF
set(UMFPACK_DIR "path/to/umfpack" CACHE STRING "Umfpack override path")
EOF

You can then use this script to populate the initial cache using the –initial-cache-file option of the configure script, like so

path/to/configure gcc-opt-umfpack-hypre --no_external_libs --initial-cache-file=initial-cache.cmake

CMake will then find and use the preinstalled UMFPACK, and download and build HYPRE.

Downloading thirdparty dependencies

Thirdparty dependencies that could not be found on the system will be downloaded and included in the build. For some of the thirdparty depedencies FEAT can make use of the depedencies build system. In these cases the configure output of the dependency will be part of FEATs configure output. This is intended.

Note: FEAT fetches any missing dependencies at configure time using the FetchContent module. For dependencies that support doing so, the dependencies CMake build system is directly added as a sub-build. For other dependencies FEAT works around the dependency and manually builds it "from the outside". Apart from the configure output, the difference is invisible to the user.

CMake will create a _deps directory inside your build directory. This directory will contain the donwloaded (and extracted) thirdparty dependencies, as well as the build directories for these dependencies.

Note: The location (and name) of the _deps folder is determined by the FETCHCONTENT_BASE_DIR CMake variable.

If you do not want FEAT to download any thirdparty dependencies, you can disable this behaviour via the --no_external_download flag of the configure script. In this case all requested thirdparty dependencies have to be installed and findable, otherwise the configuring fails.

path/to/configure gcc-opt --no_external_download

Note: The --no-external-download flag sets the FEAT_NO_EXTERNAL_DOWNLOAD CMake flag to ON

For FEAT developers

Thirdparty dependency support is implemented in thirdparty/CMakeLists.txt. Find modules and other scripts are located in build_system/cmake.

Author: Markus Muegge