The Rust ecosystem is full of a data structure implementations that may be useful in machine learning. You can find multi-dimensional arrays, matrices, graphs, and a large list of tree libraries.

num has emerged as a de facto choice for numerical types, and a few other crates listed here show promise, but most ML frameworks have opted to implement their own data structures, so it’s too early to answer affirmatively to “Are we numpy yet?”

The list below is still lacking, so for more specific data structures don’t forget to search crates.io.