Building from Source

Build from source when a pre-built package is not an option — custom configure flags, an unsupported distro, or contributing back. For everyday use, prefer a pre-built package.

First install the build dependencies for your platform.

Ubuntu / macOS

git clone https://github.com/rapastranac/gempba.git
cd gempba
cmake -B build -DGEMPBA_MULTIPROCESSING=ON   # ON = MPI flavor, OFF = multithreading
cmake --build build --parallel
sudo cmake --install build                   # optional: install system-wide

Windows (MSYS2 / MinGW64)

Open an MSYS2 MinGW64 shell, then:

git clone https://github.com/rapastranac/gempba.git
cd gempba
cmake -B build -G "MSYS Makefiles" -DGEMPBA_MULTIPROCESSING=ON
cmake --build build --parallel

CMake flags

When GemPBA is the root project (you cloned and built it directly), it defaults to a multiprocessing developer build with tests enabled. As a subproject (pulled in via CPM/add_subdirectory), every flag defaults to OFF and you opt in to what you need.

Flag	Root default	Description
`GEMPBA_MULTIPROCESSING`	`ON`	`ON` = MPI (`mpi`) flavor, `OFF` = multithreading (`mt`) flavor
`GEMPBA_HWLOC`	`ON`	Use hwloc for the hardware-topology probe (telemetry)
`GEMPBA_BUILD_TESTS`	`ON`	Build the GoogleTest suite
`GEMPBA_DEV_MODE`	`ON`	Developer-only checks; required to build the tests
`GEMPBA_DEBUG_COMMENTS`	`OFF`	Extra runtime logging
`GEMPBA_BUILD_JAVA_BINDING`	`OFF`	Build the Java JNI shared library (requires a JDK and `-DGEMPBA_JNI_CLASSIFIER=<os>-<arch>`)

Pass any flag at configure time:

cmake -B build -DGEMPBA_MULTIPROCESSING=ON -DGEMPBA_HWLOC=ON -DCMAKE_BUILD_TYPE=Release

Tests require dev mode

The test suite uses the explicit gempba::multithreading::* / gempba::multiprocessing::* forms, so it builds only with GEMPBA_DEV_MODE=ON, and the multiprocessing tests additionally require GEMPBA_MULTIPROCESSING=ON. Both are on by default for a root build.

Running tests

ctest --test-dir build --output-on-failure

Flaky tests (prefixed FLAKY_) are retried automatically in CI.

Running examples

Example programs no longer live in the gempba source tree — they moved to the sibling repository rapastranac/gempba-examples (C++) and rapastranac/gempba-java-examples (Java), where they consume GemPBA via find_package(gempba) exactly as a downstream user would. Clone one of those repos, install GemPBA (or point it at your build), and build the examples from there. See the Examples page for the catalog.