50  Build, Test, and CI

Use a debug build with unit tests for local development:

A Fortran compiler is required for the fetched reference LAPACK backend (for example gfortran). CMake downloads BLAS, LAPACK and LAPACKE from the pinned Reference-LAPACK 3.12.1 archive and verifies its SHA-256. These libraries build under the build directory’s _deps/; a system LAPACK installation is not needed. Use -DCMAKE_Fortran_COMPILER=/path/to/compiler to select a compiler explicitly. The dependency is static, position-independent, real double precision with the 32-bit integer interface. Its own tests and examples are disabled; OPALX includes eigenpair and coupled-map tests. LAPACK’s upstream Fortran optimization policy is retained; it does not change OPALX’s C++ Release flags.

The backend is host-side and serial, even in GPU builds. It introduces no GPU copies or MPI collectives into optics. Runtime deployments must provide the selected Fortran compiler runtime (for GNU on Ubuntu, libgfortran5). CI build jobs install the compiler; the serial smoke-test job installs its runtime.

cmake -S . -B build_serial \
  -DBUILD_TYPE=Debug \
  -DPLATFORMS=SERIAL \
  -DOPALX_ENABLE_UNIT_TESTS=ON
cmake --build build_serial -j 8
ctest --test-dir build_serial --output-on-failure

Repeat relevant tests with OPENMP and the target accelerator backend. A test that passes only on the serial backend is not sufficient for a performance-portable change.

Pull-request CI includes serial, OpenMP, CUDA, and HIP compilation, with SYCL coverage where the runner supports it. Compile workflows run on labeled, non-draft pull requests to master; use the compile-ci label when the change is ready for those checks. Fast regression cases are executed with the serial artifact and compared to maintained metrics.