cargo add usearchCMake builds the engine from the crate’s sources and links it as a static archive.
That build compiles the four most common dense storage types, bf16, u1x8, i8 and e4m3, and an index over any other is refused as Unsupported. NumKong is a hard dependency rather than a feature: its matrices, scalar types, and traits are this crate’s vocabulary, and it supplies the SIMD kernels.
Two features swap the implementation of the C interface the crate links, and naming both is refused:
cudacompiles the CUDA backends in and needs a toolkit at build time, withUSEARCH_CUDA_ARCHchoosing the GPU code, the release setallby default.stublinks a brute-force stand-in that answers the same verbs over the standard library alone, with exact search, seconds to build and no submodules, for testing a caller and never for shipping.
A WASI build reads the SDK from WASI_SDK_PATH and needs -C target-feature=+simd128. USEARCH_LIBRARY_DIR names a directory already holding libusearch_static.a, such as the lib/ of a prefix cmake --install build_release --component static filled, and skips the CMake build.