# SciPy Roadmap

This roadmap page contains only the most important ideas and needs for SciPy going forward. For a more detailed roadmap, including per-subpackage status, many more ideas, API stability and more, see Detailed SciPy Roadmap.

## Support for distributed arrays and GPU arrays

NumPy has split its API from its execution engine with `__array_function__` and `__array_ufunc__`. This will enable parts of SciPy to accept distributed arrays (e.g. `dask.array.Array`) and GPU arrays (e.g. `cupy.ndarray`) that implement the `ndarray` interface. At the moment it is not yet clear which algorithms will work out of the box, and if there are significant performance gains when they do. We want to create a map of which parts of the SciPy API work, and improve support over time.

In addition to making use of NumPy protocols like `__array_function__`, we can make use of these protocols in SciPy as well. That will make it possible to (re)implement SciPy functions like, e.g., those in `scipy.signal` for Dask or GPU arrays (see NEP 18 - use outside of NumPy). NumPy’s features in this areas are still evolving, see e.g. NEP 37 - A dispatch protocol for NumPy-like modules, and SciPy is an important “client” for those features.

## Performance improvements

Speed improvements, lower memory usage and the ability to parallelize algorithms are beneficial to most science domains and use cases. We have established an API design pattern for multiprocessing - using the `workers` keyword - that can be adopted in many more functions.

Enabling the use of an accelerator like Pythran, possibly via Transonic, and making it easier for users to use Numba’s `@njit` in their code that relies on SciPy functionality would unlock a lot of performance gain. That needs a strategy though, all solutions are still maturing (see for example this overview).

Finally, many individual functions can be optimized for performance. `scipy.optimize` and `scipy.interpolate` functions are particularly often requested in this respect.

## Statistics enhancements

The following `scipy.stats` enhancements and those listed in the Detailed SciPy Roadmap are of particularly high importance to the project.

- Overhaul the univariate distribution infrastructure to address longstanding issues (e.g. see gh-15928.)

- Consistently handle `nan_policy`, `axis` arguments, and masked arrays in `stats` functions (where appropriate).

## Support for more hardware platforms

SciPy now has continuous integration for ARM64 (or `aarch64`) and POWER8/9 (or `ppc64le`), and binaries are available via Miniforge. Wheels on PyPI for these platforms are now also possible (with the `manylinux2014` standard), and requests for those are becoming more frequent.

Additionally, having IBM Z (or `s390x`) in CI is now possible with TravisCI but not yet done - and `manylinux2014` wheels for that platform are also possible then. Finally, resolving open AIX build issues would help users.

## Implement sparse arrays in addition to sparse matrices

The sparse matrix formats are mostly feature-complete, however the main issue is that they act like `numpy.matrix` (which will be deprecated in NumPy at some point). What we want is sparse arrays that act like `numpy.ndarray`. This is being worked on in https://github.com/pydata/sparse, which is quite far along. The tentative plan is:

- Start depending on `pydata/sparse` once it’s feature-complete enough (it still needs a CSC/CSR equivalent) and okay performance-wise.

- Indicate in the documentation that for new code users should prefer `pydata/sparse` over sparse matrices.

- When NumPy deprecates `numpy.matrix`, vendor that or maintain it as a stand-alone package.