Function index_binary_factory 

pub fn index_binary_factory<D>(
    d: u32,
    description: D,
) -> Result<BinaryIndexImpl>
where
    D: AsRef<str>,

Use the index binary factory to create a native instance of a Faiss binary index, for d-dimensional vectors. description should follow the exact guidelines as the native Faiss interface (see the Faiss wiki for examples).

These indexes store vectors as array of bytes, so that a vector of size d takes only d / 8 bytes in memory. Only vectors with sizes multiple of 8 are supported.

Error

This function returns an error if the description contains any byte with the value \0 (since it cannot be converted to a C string), or if the internal index factory operation fails.