Nabla.jl is a reverse-mode automatic differentiation package targetting machine learning use cases. As such, we have (for example) prioritised support for linear algebra optimisations and higher-order functions over the ability to take higher-order derivatives (Nabla currently only supports first-order derivatives).
The latest docs, and code in the examples folder, best indicate how to use the package. Given the early stage of development, we anticipate a number of bugs and performance issues. If you encounter any of these or have any particular feature requests, please raise an issue and let us know.