Build Errors
Each entry is a symptom, its cause, and a solution. The exact wording of messages from your compiler and from CMake depends on their versions; the entries describe the situation rather than quote every tool's text.
Missing LAPACK or LAPACKE
| Symptom | CMake fails while configuring, reporting that it could not find LAPACK, or could not find lapacke.h |
| Cause | The matrix-product-state engine needs LAPACKE for its singular value decompositions, and the development packages are not installed |
| Solution | On Ubuntu: sudo apt install liblapacke-dev liblapack-dev libblas-dev. On macOS LAPACK comes from the Accelerate framework (macOS is unverified). On Windows, run scripts\fetch-openblas-windows.ps1, or set MENOS_OPENBLAS_ROOT to an LP64 OpenBLAS release directory |
OpenBLAS is ILP64 (Windows)
| Symptom | CMake stops with ... is an ILP64 OpenBLAS; use the LP64 (OpenBLAS-<version>-x64.zip) release |
| Cause | MENOS passes 32-bit LAPACK integers; the x64-64 OpenBLAS release uses 64-bit ones |
| Solution | Use the OpenBLAS-<version>-x64.zip release, which scripts\fetch-openblas-windows.ps1 downloads |
CUDA requested with MSVC
| Symptom | CMake stops with MENOS_ENABLE_CUDA is not supported with MSVC |
| Cause | Native Windows builds are CPU-only; CUDA on Windows is a recorded deferral (docs/adr/0022) |
| Solution | Configure without MENOS_ENABLE_CUDA, or build the CUDA backend under WSL |
MSVC 14.51 refused
| Symptom | CMake stops with MSVC 19.51... (toolset 14.51) miscompiles MENOS |
| Cause | The 14.51 toolset's optimizer reads an uninitialised loop bound in MENOS's planner code, so runs crash, hang or compute a wrong result (measured, docs/adr/0022 section 3.1). The 14.50 toolset compiles it correctly |
| Solution | Install the "MSVC v14.50" toolset in the Visual Studio Installer (component Microsoft.VisualStudio.Component.VC.14.50.18.0.x86.x64) and enter the developer environment with -vcvars_ver=14.50; scripts\verify-windows.ps1 does this |
cl, ninja or the Windows SDK not found
| Symptom | cmake --preset windows-release cannot find the C++ compiler, Ninja or system headers |
| Cause | The windows-* presets need a Visual Studio x64 developer environment |
| Solution | Run scripts\verify-windows.ps1, which enters one, or open a "x64 Native Tools" prompt first |
Compiler too old
| Symptom | Compile errors about unsupported C++20 features |
| Cause | MENOS needs C++20: GCC 12+, Clang 16+, or AppleClang 15+; on Windows, MSVC from Visual Studio 2026 is what is tested |
| Solution | Install a newer compiler and tell CMake to use it (CXX=g++-13 or -DCMAKE_CXX_COMPILER=…) |
CMake too old
| Symptom | CMake stops immediately, saying a newer version is required |
| Cause | The project requires CMake 3.25 or newer |
| Solution | Install a newer CMake (for example from your distribution's backports, or pip install cmake) |
Unsupported operating system
| Symptom | error: "menos supports only Linux, macOS and Windows" |
| Cause | The source refuses to build on other operating systems |
| Solution | Build on Linux, macOS or Windows (x64, MSVC) |
scikit-build-core or nanobind not found
| Symptom | The Python build fails before compiling, about a missing build backend |
| Cause | The build tools are fetched by the installer into an isolated environment; this fails if you disabled build isolation without installing them |
| Solution | Install with default isolation, or first install the pinned tools: scikit-build-core==1.0.3 and nanobind==3.1.0 |
Out of memory while compiling
| Symptom | The compiler is killed partway through the build |
| Cause | Parallel compilation of large translation units on a machine with little memory |
| Solution | Build with fewer parallel jobs, for example cmake --build --preset release -j2 |
clang-format or clang-tidy not found
| Symptom | scripts/verify.sh fails at its first stages |
| Cause | The full verification script runs formatting and static analysis, which need those tools |
| Solution | Install clang-format and clang-tidy. They are development-only and are not needed to use MENOS |
CUDA build errors
See Troubleshooting CUDA.