This crate is used internally by TinyChain to provide the Tensor data structure. You can enable it using the tensor feature (e.g. cargo build --release --features=tensor). It requires linking to ArrayFire version 3.8 in order to compile and run. You can download and install ArrayFire by following the instructions at http://arrayfire.org/docs/installing.htm. You'll also have follow the instructions for the ArrayFire Rust crate to set the AF_PATH and LD_LIBRARY_PATH environment variables.
For more information on TinyChain, see http://github.com/haydnv/tinychain