Installation

JAX-CIP builds from source with Meson and runs its programs through cyxla. CI tests it on Linux x86-64 with Python 3.12 and 3.13.

SCIP

The extension modules link SCIP 10.1 with SoPlex and Ipopt from the SCIP_jll binaries that Julia publishes. meson-jll turns those packages into Meson wraps, and the repository commits the wraps for every platform under subprojects, pinned by meson-jll.lock. Meson downloads the tarballs it needs on the first build, so you don't need SCIP installed on the system.

PJRT plugin

JAX-CIP runs its programs through the PJRT C API, outside the Python interpreter, so that SCIP's callbacks never take the GIL. cyxla compiles the programs and declares the functions that run them. jaxlib links its CPU client statically and ships no plugin library, so the CPU plugin is a separate wheel, cyxla-pjrt-cpu. JAX-CIP depends on cyxla[cpu], which installs both, so uv sync needs no further step.

cyxla.initialize loads another plugin, or the same one with other options. Call it before compiling the first problem. The cyxla documentation describes the plugins and their options.

The package

git clone https://github.com/nardi/jax-cip
cd jax-cip
uv sync

uv sync installs the package in editable mode with the development tools, and Meson will rebuild the extension modules when you import them after a change. These development builds trace lines in the Cython modules for coverage, which makes the callbacks several times slower. For timing, reinstall the package without tracing. The --no-config flag stops uv from adding the coverage setting in pyproject.toml, and uv run --no-sync stops it from rebuilding the package with that setting:

uv pip install --no-config --no-deps --no-build-isolation --reinstall -e . \
    -C setup-args=-Dcoverage=false
uv run --no-sync pytest benchmarks -o addopts="" --benchmark-only

Tests

The tests have two groups. The unit tests solve small problems and cover all the code, and uv run pytest -m unit runs only them. The integration tests compare configurations with native SCIP, run longer solves and start new processes. The code blocks of the README and of these pages count as integration tests as well, and uv run pytest -m integration runs them. The MINLPLib instances need the --minlplib option.

Environment variables

Variable	Meaning
CYXLA_PJRT_PLUGIN	Path of a PJRT plugin that replaces the installed ones
CYXLA_CACHE_DIR	Directory of the disk cache, ~/.cache/cyxla if unset
JAXCIP_MINLPLIB_DIR	Directory of the MINLPLib instances for the test suite
JAXCIP_MINLPLIB_RESULTS	File that the MINLPLib suite appends its results to