Metadata-Version: 2.1
Name: ribs
Version: 0.6.2
Summary: A bare-bones Python library for quality diversity optimization.
Home-page: https://github.com/icaros-usc/pyribs
Author: ICAROS Lab pyribs Team
Author-email: team@pyribs.org
License: MIT license
Keywords: ribs
Classifier: Development Status :: 4 - Beta
Classifier: Intended Audience :: Developers
Classifier: Intended Audience :: Education
Classifier: Intended Audience :: Science/Research
Classifier: License :: OSI Approved :: MIT License
Classifier: Natural Language :: English
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.8
Classifier: Programming Language :: Python :: 3.9
Classifier: Programming Language :: Python :: 3.10
Classifier: Programming Language :: Python :: 3.11
Classifier: Topic :: Scientific/Engineering
Classifier: Topic :: Scientific/Engineering :: Mathematics
Classifier: Topic :: Scientific/Engineering :: Artificial Intelligence
Requires-Python: >=3.8.0
Description-Content-Type: text/markdown
Provides-Extra: visualize
Provides-Extra: all
Provides-Extra: dev
License-File: LICENSE

# pyribs

|             Website              |                     Source                     |                    Docs                    |                    Paper                     |                                                                   Twitter                                                                    |
| :------------------------------: | :--------------------------------------------: | :----------------------------------------: | :------------------------------------------: | :------------------------------------------------------------------------------------------------------------------------------------------: |
| [pyribs.org](https://pyribs.org) | [GitHub](https://github.com/icaros-usc/pyribs) | [docs.pyribs.org](https://docs.pyribs.org) | [pyribs.org/paper](https://pyribs.org/paper) | [![Twitter](https://img.shields.io/badge/twitter-%231DA1F2.svg?&style=flat-square&logo=twitter&logoColor=white)](https://twitter.com/pyribs) |

|                                                       PyPI                                                        |                                                               Conda                                                                |                                                                                                      CI/CD                                                                                                       |                                                                   Docs Status                                                                    |
| :---------------------------------------------------------------------------------------------------------------: | :--------------------------------------------------------------------------------------------------------------------------------: | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: | :----------------------------------------------------------------------------------------------------------------------------------------------: |
| [![PyPI](https://img.shields.io/pypi/v/ribs.svg?style=flat-square&color=blue)](https://pypi.python.org/pypi/ribs) | [![Conda Recipe](https://img.shields.io/badge/recipe-pyribs-green.svg?style=flat-square)](https://anaconda.org/conda-forge/pyribs) | [![Tests](https://img.shields.io/endpoint.svg?url=https%3A%2F%2Factions-badge.atrox.dev%2Ficaros-usc%2Fpyribs%2Fbadge&style=flat-square)](https://github.com/icaros-usc/pyribs/actions?query=workflow%3A"Tests") | [![Documentation Status](https://readthedocs.org/projects/ribs/badge/?version=stable&style=flat-square)](https://readthedocs.org/projects/ribs/) |

A _bare-bones_ Python library for quality diversity (QD) optimization. Pyribs
implements the highly modular _Rapid Illumination of Behavior Space (RIBS)_
framework for QD optimization. Pyribs is also the official implementation of
Covariance Matrix Adaptation MAP-Elites (CMA-ME), Covariance Matrix Adaptation
MAP-Elites via a Gradient Arborescence (CMA-MEGA), Covariance Matrix Adaptation
MAP-Annealing (CMA-MAE), and scalable variants of CMA-MAE.

## Overview

![Types of Optimization](readme_assets/optimization_types.png)

[Quality diversity (QD) optimization](https://arxiv.org/abs/2012.04322) is a
subfield of optimization where solutions generated cover every point in a
_measure_ space while simultaneously maximizing (or minimizing) a single
_objective_. QD algorithms within the MAP-Elites family of QD algorithms produce
heatmaps (archives) as output where each cell contains the best discovered
representative of a region in measure space.

> In the QD literature, measure function outputs have also been referred to as
> "behavioral characteristics," "behavior descriptors," or "feature
> descriptors."

Recent years have seen the development of a large number of QD algorithms. To
represent these and future algorithms, we have developed the highly modular RIBS
framework. RIBS divides a QD algorithm into three components:

- An **archive**, which saves generated solutions within measure space.
- One or more **emitters**, where each emitter is an algorithm which generates
  new candidate solutions and responds to feedback about how the solutions were
  evaluated and how they were inserted into the archive.
- A **scheduler** which controls the interaction of the **archive** and
  **emitters**. The **scheduler** also provides an interface for requesting new
  candidate solutions and telling the algorithm how candidates performed.

By interchanging these components, a user can compose a large number of QD
algorithms.

Pyribs is an implementation of the RIBS framework designed to support a wide
range of users, from beginners entering the field to experienced researchers
seeking to develop new algorithms. Pyribs achieves these goals by embodying
three principles:

- **Simple:** Centered _only_ on components that are absolutely necessary to run
  a QD algorithm, allowing users to combine the framework with other software
  frameworks.
- **Flexible:** Capable of representing a wide range of current and future QD
  algorithms, allowing users to easily create or modify components.
- **Accessible:** Easy to install and learn, particularly for beginners with
  limited computational resources.

In contrast to other QD libraries, pyribs is "bare-bones." For example, like
[pycma](https://pypi.org/project/cma/), pyribs focuses solely on optimizing
fixed-dimensional continuous domains. Focusing on this one commonly-occurring
problem allows us to optimize the library for performance as well as ease of
use. Refer to the list of [additional QD libraries](#additional-qd-libraries)
below if you need greater performance or have additional use cases.

Following the RIBS framework (shown in the figure below), a standard algorithm
in pyribs operates as follows:

1. The user calls the `ask()` method on the scheduler. The scheduler requests
   solutions from each emitter by calling the emitter's `ask()` method.
2. The user evaluates solutions to obtain the objective and measure values.
3. The user passes the evaluations to the scheduler's `tell()` method. The
   scheduler adds the solutions into the archive and receives feedback. The
   scheduler passes this feedback along with the evaluated solutions to each
   emitter's `tell()` method, and each emitter then updates its internal state.

![The RIBS framework](readme_assets/ribs.png)

## Paper

Two years after the initial release of pyribs, we released a paper that
elaborates on the RIBS framework and the design decisions behind pyribs! For
more information on this paper, see [here](https://pyribs.org/paper).

## Citation

If you use pyribs in your research, please consider citing our
[GECCO 2023 paper](https://dl.acm.org/doi/10.1145/3583131.3590374) as follows.
Also consider citing any algorithms you use as shown
[below](#citing-algorithms-in-pyribs).

```
@inproceedings{10.1145/3583131.3590374,
  author = {Tjanaka, Bryon and Fontaine, Matthew C and Lee, David H and Zhang, Yulun and Balam, Nivedit Reddy and Dennler, Nathaniel and Garlanka, Sujay S and Klapsis, Nikitas Dimitri and Nikolaidis, Stefanos},
  title = {Pyribs: A Bare-Bones Python Library for Quality Diversity Optimization},
  year = {2023},
  isbn = {9798400701191},
  publisher = {Association for Computing Machinery},
  address = {New York, NY, USA},
  url = {https://doi.org/10.1145/3583131.3590374},
  doi = {10.1145/3583131.3590374},
  abstract = {Recent years have seen a rise in the popularity of quality diversity (QD) optimization, a branch of optimization that seeks to find a collection of diverse, high-performing solutions to a given problem. To grow further, we believe the QD community faces two challenges: developing a framework to represent the field's growing array of algorithms, and implementing that framework in software that supports a range of researchers and practitioners. To address these challenges, we have developed pyribs, a library built on a highly modular conceptual QD framework. By replacing components in the conceptual framework, and hence in pyribs, users can compose algorithms from across the QD literature; equally important, they can identify unexplored algorithm variations. Furthermore, pyribs makes this framework simple, flexible, and accessible, with a user-friendly API supported by extensive documentation and tutorials. This paper overviews the creation of pyribs, focusing on the conceptual framework that it implements and the design principles that have guided the library's development. Pyribs is available at https://pyribs.org},
  booktitle = {Proceedings of the Genetic and Evolutionary Computation Conference},
  pages = {220–229},
  numpages = {10},
  keywords = {framework, quality diversity, software library},
  location = {Lisbon, Portugal},
  series = {GECCO '23}
}
```

## Usage

Here we show an example application of CMA-ME in pyribs. To initialize the
algorithm, we first create:

- A 2D **GridArchive** where each dimension contains 20 cells across the range
  [-1, 1].
- Three instances of **EvolutionStrategyEmitter**, all of which start from the
  search point **0** in 10-dimensional space and a Gaussian sampling
  distribution with standard deviation 0.1.
- A **Scheduler** that combines the archive and emitters together.

After initializing the components, we optimize (pyribs maximizes) the negative
10-D Sphere function for 1000 iterations. Users of
[pycma](https://pypi.org/project/cma/) will be familiar with the ask-tell
interface (which pyribs adopted). First, the user must `ask` the scheduler for
new candidate solutions. After evaluating the solution, they `tell` the
scheduler the objectives and measures of each candidate solution. The algorithm
then populates the archive and makes decisions on where to sample solutions
next. Our toy example uses the first two parameters of the search space as
measures.

```python
import numpy as np

from ribs.archives import GridArchive
from ribs.emitters import EvolutionStrategyEmitter
from ribs.schedulers import Scheduler

archive = GridArchive(
    solution_dim=10,
    dims=[20, 20],
    ranges=[(-1, 1), (-1, 1)],
)
emitters = [
    EvolutionStrategyEmitter(
        archive,
        x0=[0.0] * 10,
        sigma0=0.1,
    ) for _ in range(3)
]
scheduler = Scheduler(archive, emitters)

for itr in range(1000):
    solutions = scheduler.ask()

    # Optimize the 10D negative Sphere function.
    objective_batch = -np.sum(np.square(solutions), axis=1)

    # Measures: first 2 coordinates of each 10D solution.
    measures_batch = solutions[:, :2]

    scheduler.tell(objective_batch, measures_batch)
```

To visualize this archive with Matplotlib, we then use the
`grid_archive_heatmap` function from `ribs.visualize`.

```python
import matplotlib.pyplot as plt
from ribs.visualize import grid_archive_heatmap

grid_archive_heatmap(archive)
plt.show()
```

![Sphere heatmap](readme_assets/sphere_heatmap.png)

For more information, refer to the [documentation](https://docs.pyribs.org/).

## Installation

pyribs supports Python 3.8 and above. Earlier Python versions may work but are
not officially supported. To find the installation command for your system
(including for installing from source), visit the
[installation selector](https://pyribs.org/#installation) on our website.

To test your installation, import pyribs and print the version with this
command:

```bash
python -c "import ribs; print(ribs.__version__)"
```

You should see a version number in the output.

## Documentation

See here for the documentation: <https://docs.pyribs.org>

To serve the documentation locally, clone the repo and install the development
requirements with

```bash
pip install -e .[dev]
```

Then run

```bash
make servedocs
```

This will open a window in your browser with the documentation automatically
loaded. Furthermore, every time you make changes to the documentation, the
preview will also reload.

## Contributors

pyribs is developed and maintained by the [ICAROS Lab](http://icaros.usc.edu) at
USC. For information on contributing to the repo, see
[CONTRIBUTING](./CONTRIBUTING.md).

- [Bryon Tjanaka](https://btjanaka.net)
- [Matthew C. Fontaine](https://scholar.google.com/citations?user=RqSvzikAAAAJ)
- [David H. Lee](https://github.com/itsdawei)
- [Yulun Zhang](https://github.com/lunjohnzhang)
- [Nivedit Reddy Balam](https://www.linkedin.com/in/nivedit-reddy)
- [Nathan Dennler](https://ndennler.github.io/)
- [Sujay S. Garlanka](https://sujaygarlanka.com)
- Nikitas Klapsis
- [Robby Costales](https://robbycostales.com)
- [Sam Sommerer](https://github.com/sam-sommerer)
- [Vincent Vu](https://vuvincent.com/)
- [Stefanos Nikolaidis](https://stefanosnikolaidis.net)

We thank [Amy K. Hoover](http://amykhoover.com/) and
[Julian Togelius](http://julian.togelius.com/) for their contributions deriving
the CMA-ME algorithm.

## Users

pyribs users include:

<!-- Alphabetical order -->

- [Adam Gaier (Autodesk Research)](https://scholar.google.com/citations?user=GGyARB8AAAAJ)
- [Adaptive & Intelligent Robotics Lab (Imperial College London)](https://www.imperial.ac.uk/adaptive-intelligent-robotics)
- [Chair of Statistical Learning and Data Science (LMU Munich)](https://www.slds.stat.uni-muenchen.de/)
- [Game Innovation Lab (New York University)](https://game.engineering.nyu.edu)
- [Giovanni Iacca (University of Trento)](https://sites.google.com/site/giovanniiacca/)
- [HUAWEI Noah's Ark Lab](https://github.com/huawei-noah)
- [ICAROS Lab (University of Southern California)](http://icaros.usc.edu/)
- [Jacob Schrum (Southwestern University)](https://github.com/schrum2/PyribsForGameGAN)
- [Lenia Research](https://lenia.world)
- [Paul Kent (The University of Warwick)](https://warwick.ac.uk/fac/sci/mathsys/people/students/2018intake/kent/)
- [Various](https://github.com/ganyariya/mario_pytorch)
  [researchers](https://direct.mit.edu/isal/proceedings/isal/33/112256) at the
  University of Tsukuba

### Publications

For the list of publications which use pyribs, refer to our
[Google Scholar entry](https://scholar.google.com/scholar?cites=1780392371068190395).

### Software

See the
[GitHub dependency graph](https://github.com/icaros-usc/pyribs/network/dependents)
for the public GitHub repositories which depend on pyribs.

## Citing Algorithms in pyribs

If you use the following algorithms, please also cite their relevant papers:

- **CMA-ME:** [Fontaine 2020](https://dl.acm.org/doi/10.1145/3377930.3390232)
  ```
  @inproceedings{10.1145/3377930.3390232,
    author = {Fontaine, Matthew C. and Togelius, Julian and Nikolaidis, Stefanos and Hoover, Amy K.},
    title = {Covariance Matrix Adaptation for the Rapid Illumination of Behavior Space},
    year = {2020},
    isbn = {9781450371285},
    publisher = {Association for Computing Machinery},
    address = {New York, NY, USA},
    url = {https://doi.org/10.1145/3377930.3390232},
    doi = {10.1145/3377930.3390232},
    booktitle = {Proceedings of the 2020 Genetic and Evolutionary Computation Conference},
    pages = {94–102},
    numpages = {9},
    location = {Canc\'{u}n, Mexico},
    series = {GECCO '20}
  }
  ```
- **CMA-MEGA:**
  [Fontaine 2021](https://proceedings.neurips.cc/paper/2021/hash/532923f11ac97d3e7cb0130315b067dc-Abstract.html)
  ```
  @inproceedings{NEURIPS2021_532923f1,
   author = {Fontaine, Matthew and Nikolaidis, Stefanos},
   booktitle = {Advances in Neural Information Processing Systems},
   editor = {M. Ranzato and A. Beygelzimer and Y. Dauphin and P.S. Liang and J. Wortman Vaughan},
   pages = {10040--10052},
   publisher = {Curran Associates, Inc.},
   title = {Differentiable Quality Diversity},
   url = {https://proceedings.neurips.cc/paper/2021/file/532923f11ac97d3e7cb0130315b067dc-Paper.pdf},
   volume = {34},
   year = {2021}
  }
  ```
- **CMA-MAE:** [Fontaine 2022](https://arxiv.org/abs/2205.10752)
  ```
  @misc{cmamae,
    doi = {10.48550/ARXIV.2205.10752},
    url = {https://arxiv.org/abs/2205.10752},
    author = {Fontaine, Matthew C. and Nikolaidis, Stefanos},
    keywords = {Machine Learning (cs.LG), Artificial Intelligence (cs.AI), FOS: Computer and information sciences, FOS: Computer and information sciences},
    title = {Covariance Matrix Adaptation MAP-Annealing},
    publisher = {arXiv},
    year = {2022},
    copyright = {arXiv.org perpetual, non-exclusive license}
  }
  ```
- **Scalable CMA-MAE:** [Tjanaka 2022](https://arxiv.org/abs/2210.02622)
  ```
  @misc{scalablecmamae,
        title={Training Diverse High-Dimensional Controllers by Scaling Covariance Matrix Adaptation MAP-Annealing},
        author={Bryon Tjanaka and Matthew C. Fontaine and Aniruddha Kalkar and Stefanos Nikolaidis},
        year={2022},
        eprint={2210.02622},
        archivePrefix={arXiv},
        primaryClass={cs.RO}
  }
  ```

## Additional QD Libraries

- [QDax](https://github.com/adaptive-intelligent-robotics/QDax): Implementations
  of QD algorithms in JAX. QDax is suitable if you want to run entire QD
  algorithms on hardware accelerators in a matter of minutes, and it is
  particularly useful if you need to interface with Brax environments.
- [qdpy](https://gitlab.com/leo.cazenille/qdpy/): Python implementations of a
  wide variety of QD algorithms.
- [sferes](https://github.com/sferes2/sferes2): Contains C++ implementations of
  QD algorithms; can also handle discrete domains.

## License

pyribs is released under the
[MIT License](https://github.com/icaros-usc/pyribs/blob/master/LICENSE).

## Credits

The pyribs package was initially created with
[Cookiecutter](https://github.com/audreyr/cookiecutter) and the
[audreyr/cookiecutter-pypackage](https://github.com/audreyr/cookiecutter-pypackage)
project template.


# History

## 0.6.2

Small patch release due to installation issues in our tutorials.

### Changelog

#### API

- Import ribs[visualize] in tutorials that need it ({pr}`379`)

#### Improvements

- Switch to a branch-based release model ({pr}`382`)

## 0.6.1

(This release was removed)

## 0.6.0

### Changelog

#### API

- Drop Python 3.7 support and upgrade dependencies ({pr}`350`)
- Add visualization of QDax repertoires ({pr}`353`)
- Improve cvt_archive_heatmap flexibility ({pr}`354`)
- Clip Voronoi regions in cvt_archive_heatmap ({pr}`356`)
- **Backwards-incompatible:** Allow using kwargs for colorbar in
  parallel_axes_plot ({pr}`358`)
  - Removes cbar_orientaton and cbar_pad args for parallel_axes_plot
- Add `rasterized` arg for heatmaps ({pr}`359`)
- Support 1D cvt_archive_heatmap ({pr}`362`)
- Add 3D plots for CVTArchive ({pr}`371`)
- Add visualization of 3D QDax repertoires ({pr}`373`)
- Enable plotting custom data in visualizations ({pr}`374`)

#### Documentation

- Use dask instead of multiprocessing for lunar lander tutorial ({pr}`346`)
- pip install swig before gymnasium[box2d] in lunar lander tutorial ({pr}`346`)
- Fix lunar lander dependency issues ({pr}`366`, {pr}`367`)
- Simplify DQD tutorial imports ({pr}`369`)
- Improve visualization docs examples ({pr}`372`)

#### Improvements

- Improve developer workflow with pre-commit ({pr}`351`, {pr}`363`)
- Speed up 2D cvt_archive_heatmap by order of magnitude ({pr}`355`)
- Refactor visualize module into multiple files ({pr}`357`)
- Refactor visualize tests into multiple files ({pr}`370`)
- Add GitHub link roles in documentation ({pr}`361`)
- Refactor argument validation utilities ({pr}`365`)
- Use Conda envs in all CI jobs ({pr}`368`)
- Split tutorial CI into multiple jobs ({pr}`375`)

## 0.5.2

This release contains miscellaneous edits to our documentation from v0.5.1.
Furthermore, the library is updated to support Python 3.11, removed deprecated
options, and strengthened with more robust checks and error messages in the
schedulers.

### Changelog

#### API

- Support Python 3.11 ({pr}`342`)
- Check that emitters passed in are lists/iterables in scheduler ({pr}`341`)
- Fix Matplotlib `get_cmap` deprecation ({pr}`340`)
- **Backwards-incompatible:** Default `plot_centroids` to False when plotting
  ({pr}`339`)
- Raise error messages when `ask` is called without `ask_dqd` ({pr}`338`)

#### Documentation

- Add BibTex citation for GECCO 2023 ({pr}`337`)

#### Improvements

- Update distribution dependencies ({pr}`344`)

## 0.5.1

This release contains miscellaneous edits to our documentation from v0.5.0.
There were no changes to library functionality in this release.

## 0.5.0

To learn about this release, see our page on What's New in v0.5.0:
https://docs.pyribs.org/en/stable/whats-new.html

### Changelog

#### API

- Schedulers warn if no solutions are inserted into archive ({pr}`320`)
- Implement `BanditScheduler` ({pr}`299`)
- **Backwards-incompatible:** Implement Scalable CMA-ES Optimizers ({pr}`274`,
  {pr}`288`)
- Make ribs.emitters.opt public ({pr}`281`)
- Add normalized QD score to ArchiveStats ({pr}`276`)
- **Backwards-incompatible:** Make ArchiveStats a dataclass ({pr}`275`)
- **Backwards-incompatible:** Add shape checks to `tell()` and `tell_dqd()`
  methods ({pr}`269`)
- Add method for computing CQD score in archives ({pr}`252`)
- **Backwards-incompatible:** Deprecate positional arguments in constructors
  ({pr}`261`)
- **Backwards-incompatible:** Allow custom initialization in Gaussian and
  IsoLine emitters ({pr}`259`, {pr}`265`)
- Implement CMA-MAE archive thresholds ({pr}`256`, {pr}`260`, {pr}`314`)
  - Revive the old implementation of `add_single` removed in ({pr}`221`)
  - Add separate tests for `add_single` and `add` with single solution
- Fix all examples and tutorials ({pr}`253`)
- Add restart timer to `EvolutionStrategyEmitter` and
  `GradientArborescenceEmitter`({pr}`255`)
- Rename fields and update documentation ({pr}`249`, {pr}`250`)
  - **Backwards-incompatible:** rename `Optimizer` to `Scheduler`
  - **Backwards-incompatible:** rename `objective_value` to `objective`
  - **Backwards-incompatible:** rename `behavior_value`/`bcs` to `measures`
  - **Backwards-incompatible:** `behavior_dim` in archives is now `measure_dim`
  - Rename `n_solutions` to `batch_size` in `Scheduler`.
- Add `GradientArborescenceEmitter`, which is used to implement CMA-MEGA
  ({pr}`240`, {pr}`263`, {pr}`264`, {pr}`282`, {pr}`321`)
- Update emitter `tell()` docstrings to no longer say "Inserts entries into
  archive" ({pr}`247`)
- Expose `emitter.restarts` as a property ({pr}`248`)
- Specify that `x0` is 1D for all emitters ({pr}`244`)
- Add `best_elite` property for archives ({pr}`237`)
- Rename methods in ArchiveDataFrame and rename as_pandas behavior columns
  ({pr}`236`)
- Re-run CVTArchive benchmarks and update CVTArchive ({pr}`235`, {pr}`329`)
  - **Backwards-incompatible:** `use_kd_tree` now defaults to True since the k-D
    tree is always faster than brute force in benchmarks.
- Allow adding solutions one at a time in optimizer ({pr}`233`)
- Minimize numba usage ({pr}`232`)
- **Backwards-incompatible:** Implement batch addition in archives ({pr}`221`,
  {pr}`242`)
  - `add` now adds a batch of solutions to the archive
  - `add_single` adds a single solution
- `emitter.tell` now takes in `status_batch` and `value_batch` ({pr}`227`)
- Make epsilon configurable in archives ({pr}`226`)
- **Backwards-incompatible:** Remove ribs.factory ({pr}`225`, {pr}`228`)
- **Backwards-incompatible:** Replaced `ImprovementEmitter`,
  `RandomDirectionEmitter`, and `OptimizingEmitter` with
  `EvolutionStrategyEmitter` ({pr}`220`, {pr}`223`, {pr}`278`)
- Raise ValueError for incorrect array shapes in archive methods ({pr}`219`)
- Introduced the Ranker object, which is responsible for ranking the solutions
  based on different objectives ({pr}`209`, {pr}`222`, {pr}`245`)
- Add index_of_single method for getting index of measures for one solution
  ({pr}`214`)
- **Backwards-incompatible:** Replace elite_with_behavior with retrieve and
  retrieve_single in archives ({pr}`213`, {pr}`215`, {pr}`295`)
- **Backwards-incompatible:** Replace get_index with batched index_of method in
  archives ({pr}`208`)
  - Also added `grid_to_int_index` and `int_to_grid_index` methods for
    `GridArchive` and `SlidingBoundariesArchive`
- **Backwards-incompatible:** Made it such that each archive is initialized
  fully in its constructor instead of needing a separate
  .initialize(solution_dim) call ({pr}`200`)
- **Backwards-incompatible:** Add `sigma`, `sigma0` options to
  `gaussian_emitter` and `iso_line_emitter` ({pr}`199`)
  - `gaussian_emitter` constructor requires `sigma`; `sigma0` is optional.
  - `iso_line_emitter` constructor takes in optional parameter `sigma0`.
- **Backwards-incompatible:** Add `cbar`, `aspect` options for
  `cvt_archive_heatmap` ({pr}`197`)
- **Backwards-incompatible:** Add `aspect` option to `grid_archive_heatmap` +
  support for 1D heatmaps ({pr}`196`)
  - `square` option no longer works
- **Backwards-incompatible:** Add `cbar` option to `grid_archive_heatmap`
  ({pr}`193`)
- **Backwards-incompatible:** Replace `get_random_elite()` with batched
  `sample_elites()` method ({pr}`192`)
- **Backwards-incompatible:** Add EliteBatch and rename fields in Elite
  ({pr}`191`)
- **Backwards-incompatible:** Rename bins to cells for consistency with
  literature ({pr}`189`)
  - Archive constructors now take in `cells` argument instead of `bins`
  - Archive now have a `cells` property rather than a `bins` property
- **Backwards-incompatible:** Only use integer indices in archives ({pr}`185`)
  - `ArchiveBase`
    - Replaced `storage_dims` (tuple of int) with `storage_dim` (int)
    - `_occupied_indices` is now a fixed-size array with `_num_occupied`
      indicating its current usage, and `_occupied_indices_cols` has been
      removed
    - `index_of` must now return an integer

#### Bugs

- Fix boundary lines in sliding boundaries archive heatmap ({pr}`271`)
- Fix negative eigenvalue in CMA-ES covariance matrix ({pr}`285`)

#### Documentation

- Speed up lunar lander tutorial ({pr}`319`)
- Add DQDTutorial ({pr}`267`)
- Remove examples extra in favor of individual example deps ({pr}`306`)
- Facilitate linking to latest version of documentation ({pr}`300`)
- Update lunar lander tutorial with v0.5.0 features ({pr}`292`)
- Improve tutorial and example overviews ({pr}`291`)
- Move tutorials out of examples folder ({pr}`290`)
- Update lunar lander to use Gymnasium ({pr}`289`)
- Add CMA-MAE tutorial ({pr}`273`, {pr}`284`)
- Update README ({pr}`279`)
- Add sphinx-codeautolink to docs ({pr}`206`, {pr}`280`)
- Fix documentation rendering issues on ReadTheDocs ({pr}`205`)
- Fix typos and formatting in docstrings of `ribs/visualize.py` ({pr}`203`)
- Add in-comment type hint rich linking ({pr}`204`)
- Upgrade Sphinx dependencies ({pr}`202`)

#### Improvements

- Move threadpoolctl from optimizer to CMA-ES ({pr}`241`)
- Remove unnecessary emitter benchmarks ({pr}`231`)
- Build docs during CI/CD workflow ({pr}`211`)
- Drop Python 3.6 and add Python 3.10 support ({pr}`181`)
- Add procedure for updating changelog ({pr}`182`)
- Add 'visualize' extra ({pr}`183`, {pr}`184`, {pr}`302`)

## 0.4.0 (2021-07-19)

To learn about this release, see our blog post: https://pyribs.org/blog/0-4-0

### Changelog

#### API

- Add ribs.visualize.parallel_axes_plot for analyzing archives with
  high-dimensional BCs ({pr}`92`)
- **Backwards-incompatible:** Reduce attributes and parameters in EmitterBase to
  make it easier to extend ({pr}`101`)
- In Optimizer, support emitters that return any number of solutions in ask()
  ({pr}`101`)
- **Backwards-incompatible:** Store metadata in archives as described in
  {pr}`87` ({pr}`103`, {pr}`114`, {pr}`115`, {pr}`119`)
- **Backwards-incompatible:** Rename "index" to "index_0" in
  CVTArchive.as_pandas for API consistency ({pr}`113`)
- **Backwards-incompatible:** Make index_of() public in archives to emphasize
  each index's meaning ({pr}`128`)
- **Backwards-incompatible:** Add index to get_random_elite() and
  elite_with_behavior() in archives ({pr}`129`)
- Add clear() method to archive ({pr}`140`, {pr}`146`)
- Represent archive elites with an Elite namedtuple ({pr}`142`)
- Add len and iter methods to archives ({pr}`151`, {pr}`152`)
- Add statistics to archives ({pr}`100`, {pr}`157`)
- Improve manipulation of elites by modifying as_pandas ({pr}`123`, {pr}`149`,
  {pr}`153`, {pr}`158`, {pr}`168`)
- Add checks for optimizer array and list shapes ({pr}`166`)

#### Documentation

- Add bibtex citations for tutorials ({pr}`122`)
- Remove network training from Fooling MNIST tutorial ({pr}`161`)
- Fix video display for lunar lander in Colab ({pr}`163`)
- Fix Colab links in stable docs ({pr}`164`)

#### Improvements

- Add support for Python 3.9 ({pr}`84`)
- Test with pinned versions ({pr}`110`)
- Increase minimum required versions for scipy and numba ({pr}`110`)
- Refactor as_pandas tests ({pr}`114`)
- Expand CI/CD to test examples and tutorials ({pr}`117`)
- Tidy up existing tests ({pr}`120`, {pr}`127`)
- Fix vocab in various areas ({pr}`138`)
- Fix dependency issues in tests ({pr}`139`)
- Remove tox from CI ({pr}`143`)
- Replace "entry" with "elite" in tests ({pr}`144`)
- Use new archive API in ribs.visualize implementation ({pr}`155`)

## 0.3.1 (2021-03-05)

This release features various bug fixes and improvements. In particular, we have
added tests for SlidingBoundariesArchive and believe it is ready for more
rigorous use.

### Changelog

- Move SlidingBoundariesArchive out of experimental by adding tests and fixing
  bugs ({pr}`93`)
- Added nicer figures to the Sphere example with `grid_archive_heatmap`
  ({pr}`86`)
- Added testing for Windows and MacOS ({pr}`83`)
- Fixed package metadata e.g. description

## 0.3.0 (2021-02-05)

pyribs is now in beta. Since our alpha release (0.2.0), we have polished the
library and added new tutorials and examples to our documentation.

### Changelog

- Added a Lunar Lander example that extends the lunar lander tutorial ({pr}`70`)
- Added New Tutorial: Illuminating the Latent Space of an MNIST GAN ({pr}`78`)
- GridArchive: Added a boundaries attribute with the upper and lower bounds of
  each dimension's bins ({pr}`76`)
- Fixed a bug where CMA-ME emitters do not work with float32 archives ({pr}`74`)
- Fixed a bug where Optimizer is able to take in non-unique emitter instances
  ({pr}`75`)
- Fixed a bug where GridArchive failed for float32 due to a small epsilon
  ({pr}`81`)
- Fix issues with bounds in the SlidingBoundaryArchive ({pr}`77`)
- Added clearer error messages for archives ({pr}`82`)
- Modified the Python requirements to allow any version above 3.6.0 ({pr}`68`)
- The wheel is now fixed so that it only supports py3 rather than py2 and py3
  ({pr}`68`)
- Miscellaneous documentation fixes ({pr}`71`)

## 0.2.0 (2021-01-29)

- Alpha release

## 0.2.1 (2021-01-29)

- Package metadata fixes (author, email, url)
- Miscellaneous documentation improvements

## 0.1.1 (2021-01-29)

- Test release (now removed)

## 0.1.0 (2020-09-11)

- Test release (now removed)

## 0.0.0 (2020-09-11)

- pyribs begins
