Sparse array support.
This does not yet exist, but should eventually contain:
- Individual sparse tiles
- spartan.distarray.DistArray-like object
A normal DistArray might work, but this depends on the distribution and size of the sparse array.
Additionally, it might be nice to support infinite-dimensional “arrays”; these correspond to the more traditional key-value stores used in most distributed systems. Supporting these requires that we ensure the various high-level operators are written in a way that isn’t implicitly relying on having a known number of dimensions. (Unless this is an explicit requirement (e.g dot product)).