How HiGHS is bundled¶

A binding to a C++ library usually forces a choice on its users. Either they install the library themselves and hope the version matches, or the binding ships a copy. cyhighs takes the second path and makes it invisible. HiGHS is linked statically into the extension, so a cyhighs wheel already contains the solver. There is no separate HiGHS to install and no system package to keep in sync.

The build¶

The build is driven by scikit-build-core, which runs a CMake build behind the standard Python packaging interface. By default, instead of compiling HiGHS from source, CMake downloads the official prebuilt static-apache release archive for the target platform at a pinned version, currently 1.15.1, verifies it against a pinned checksum, extracts it, and links the static libraries it ships directly into the extension. Because the version is pinned, every wheel is built against a known solver, and the Python enumerations in cyhighs are transcribed from that same release.

The one exception is the portable Linux wheels (manylinux_2_28 and musllinux_1_2). The prebuilt archive is built against a recent glibc and cannot link inside the older manylinux/musllinux build containers, so for those wheels CMake compiles HiGHS and HiPO from source at the same pinned version (-DCYHIGHS_HIGHS_FROM_SOURCE=ON), linking a prebuilt OpenBLAS installed in the container. The result is the same statically bundled solver, just built in place.

The static-apache archive already contains the HiPO interior point solver and its bundled OpenBLAS linear algebra kernels, so the wheels carry their own linear algebra and still need nothing from the host system. The Cython source is transpiled to C and compiled against the prebuilt HiGHS headers. The binding deliberately avoids the NumPy C API. It moves array data across the boundary using typed memoryviews and the buffer protocol only, which keeps the compiled surface small and the dependency on NumPy loose.

Platform coverage¶

Wheels are published for Linux x86_64 and aarch64, macOS on Apple Silicon, and Windows on x86_64. On Linux both a manylinux_2_39 wheel (from the prebuilt archive, requiring glibc 2.39 or newer) and the more portable manylinux_2_28 (glibc 2.28 or newer) and musllinux_1_2 (Alpine and other musl distros) wheels are shipped; pip installs whichever best matches the host. There are no 32-bit wheels; that platform builds from source instead.

Licensing¶

Because the bundled build includes HiPO, which carries Apache-licensed dependencies, the static-apache archive is distributed under the Apache License 2.0, and cyhighs is released under the same license. The upstream HiGHS license and notices are included in the wheels for attribution.

What this means for you¶

Because everything is static, installing cyhighs gives you a working solver immediately. You can confirm which HiGHS version you have by asking the library directly.

from cyhighs import highs_version

version = highs_version()
print(version)
assert version.startswith("1.15")

The same is true of the infinity threshold HiGHS uses to mean unbounded. It is read from the linked library, so it always matches the compiled solver.

from cyhighs import highs_infinity

assert highs_infinity() >= 1e30

Any bound at or beyond this magnitude is treated as unbounded, so you can pass float("inf") for a free bound and the library will map it onto this value for you.