Fix TestGaussianGateApplication tests

.github/CHANGELOG.md

@@ -17,6 +17,10 @@
 
 <h3>Documentation</h3>
 
+* Modified `CONTRIBUTING.md`, `PULL_REQUEST_TEMPLATE.md`, `README.md`, and `research.rst`, to clarify that we are not accepting Pull Requests for new features at this time.
+
+* Deleted `CHALLENGES.md` since we're no longer accepting contributions for anything other than bug fixes and docs fixes.
+
 <h3>Contributors</h3>
 
 This release contains contributions from (in alphabetical order):

.github/CONTRIBUTING.md

@@ -1,23 +1,19 @@
 # Contributing to Strawberry Fields
 
 Thank you for taking the time to contribute to Strawberry Fields!
-:strawberry: :confetti_ball: :tada: :fireworks: :balloon:
 
 Strawberry Fields is a collaborative effort with the quantum photonics and quantum computation
-community - while we will continue working on adding new and exciting features to Strawberry Fields,
-we invite you to join us and suggest improvements, research ideas, or even just to discuss how
-Strawberry Fields fits into your workflow.
-
-If your contribution becomes part of Strawberry Fields, or is highlighted in our Gallery, we will
-send you some exclusive Xanadu Swag™ - including t-shirts, stickers, and more.
+community - while we are not currently working on adding new features to Strawberry Fields,
+we invite you to make a fork of this repository to add improvements, test research ideas, or fit
+Strawberry Fields into your workflow.
 
 ## How can I get involved in the community?
 
-If you want to contribute but don't know where to start, start by checking out our
+If you don't know where to start, start by checking out our
 [documentation](https://strawberryfields.readthedocs.io). Have a go working through some of the tutorials,
 and having a look at the Strawberry Fields API and code documentation to see how things work under the hood.
 
-To chat directly with the team designing and building Strawberry Fields, as well as members of our
+To chat directly with the team that designed and built Strawberry Fields, as well as members of our
 community - ranging from professors of quantum physics, to students, to those just interested in being a
 part of a rapidly growing industry - you can join our [Slack channel](https://u.strawberryfields.ai/slack).
 
@@ -27,35 +23,20 @@ Sometimes, it might take us a couple of hours to reply - please be patient!
 
 It's up to you!
 
-* **Be a part of our community** - chat to people in our Slack channel, respond to questions, and
-  provide exciting updates of the projects/experiments you are investigating with Strawberry Fields
-
-  You can even write your own Strawberry Fields tutorials, or blog about your simulation results.
-  Send us the link, and we may even add it to our Gallery or our documentation as an external resource!
+* **Be a part of our community** - chat to people in our Slack channel or our
+  [discussion forum](https://discuss.pennylane.ai/), respond to questions, and
+  provide exciting updates of the projects/experiments you are investigating with Strawberry Fields.
 
-* **Test the cutting-edge Strawberry Fields releases** - clone our GitHub repository, and keep up to
-  date with the latest features. If you run into any bugs, make a bug report on our
+* **Report bugs or contribute to our documentation** - we are not accepting Pull Requests
+  for new features at this time. We welcome contributions for bug fixes, security patches, and documentation
+  improvements only. Thank you for your understanding. If you run into any bugs, make a bug report on our
   [issue tracker](https://github.com/XanaduAI/strawberryfields/issues).
 
-* **Report bugs** - even if you are not using the development branch of Strawberry Fields, if you come
-  across any bugs or issues, make a bug report. See the next section for more details on the bug
-  reporting procedure.
-
-* **Suggest new features and enhancements** - hop on to our Slack channel, or use the GitHub issue tracker
-  and let us know what will make Strawberry Fields even better for your workflow.
-
-* **Contribute to our documentation, or to Strawberry Fields directly** - we are hoping for our documentation
-  to become an online, open-source resource for all things continuous-variable. If you would like to add
-  to it, or suggest improvements/changes, let us know - or even submit a pull request directly. All authors
-  who have contributed to the Strawberry Fields codebase will be listed alongside the latest release.
-
 * **Build an application on top of Strawberry Fields** - have an idea for an application, and Strawberry Fields
   provides the perfect computational backbone? Consider making a fully separate app that builds upon Strawberry Fields
   as a base. Ask us if you have any questions, and send a link to your application to support@xanadu.ai so we can highlight it in
   our documentation!
 
-For some inspiration, you can also check out some preprepared [contribution challenges](./CHALLENGES.md).
-
 Appetite whetted? Keep reading below for all the nitty-gritty on reporting bugs, contributing to the documentation,
 and submitting pull requests.
 
@@ -81,85 +62,21 @@ To submit a bug report, please work your way through the following checklist:
 
 ## Suggesting features, document additions, and enhancements
 
-To suggest features and enhancements, you can either use the GitHub tracker, or use the `#strawberryfields` slack
-channel. There is no template required for feature requests and enhancements, but here are a couple of suggestions
-for things to include.
-
-* **Use a clear and descriptive title**
-* **Provide a step-by-step description of the suggested feature**.
-
-  - If the feature is related to any theoretical results in continuous-variable quantum computation
-    or quantum photonics, provide any relevant equations. Alternatively, provide references to papers/preprints,
-    with the relevant sections/equations noted.
-  - If the feature is workflow-related, or related to the use of Strawberry Fields,
-    explain why the enhancement would be useful, and where/how you would like to use it.
+We are not accepting Pull Requests for new features at this time. We welcome contributions for bug fixes, security patches,
+and documentation improvements only. Thank you for your understanding.
 
 * **For documentation additions**, point us towards any relevant equations/papers/preprints,
     with the relevant sections/equations noted. Short descriptions of its use/importance would also be useful.
 
-## Pull requests
+## Forks
 
-If you would like to contribute directly to the Strawberry Fields codebase, simply make a fork of the master branch, and
-then when ready, submit a [pull request](https://help.github.com/articles/about-pull-requests). We encourage everyone
-to have a go forking and modifying the Strawberry Fields source code, however, we have a couple of guidelines on pull
-requests to ensure the main master branch of Strawberry Fields conforms to existing standards and quality.
+If you need a new or modified Strawberry Fields feature, simply make a fork of the master branch. We encourage everyone
+to have a go forking and modifying the Strawberry Fields source code. You will now have a copy of your own that you can modify!
 
 ### General guidelines
 
 * **Do not make a pull request for minor typos/cosmetic code changes** - make an issue instead.
-* **For major features, consider making an independent app** that runs on top of Strawberry Fields, rather than modifying
-  Strawberry Fields directly.
-
-### Before submitting
-
-Before submitting a pull request, please make sure the following is done:
-
-* **All new features must include a unit test.** If you've fixed a bug or added code that should be tested,
-  add a test to the test directory!
-* **All new functions and code must be clearly commented and documented.** Have a look through the source code at some of
-  the existing function docstrings - the easiest approach is to simply copy an existing docstring and modify it as appropriate.
-  If you do make documentation changes, make sure that the docs build and render correctly by running `make docs`.
-* **Ensure that the test suite passes**, by running `make test`. You can also test individual backends by running
-  `make test-backendname`. For example, if you only make changes corresponding to the Gaussian backend, you can run `make test-gaussian`.
-* **Make sure the modified code in the pull request conforms to the PEP8 coding standard.** The Strawberry Fields source code
-  conforms to [PEP8 standards](https://www.python.org/dev/peps/pep-0008/). We check all of our code against
-  [Pylint](https://www.pylint.org/). To lint modified files, simply install `pip install pylint`, and then from the source code
-  directory, run `pylint strawberryfields/path/to/file.py`.
-
-### Submitting the pull request
-* When ready, submit your fork as a [pull request](https://help.github.com/articles/about-pull-requests) to the Strawberry
-  Fields repository, filling out the [pull request template](./PULL_REQUEST_TEMPLATE.md). This template is added automatically
-  to the comment box when you create a new issue.
-
-* When describing the pull request, please include as much detail as possible regarding the changes made/new features
-  added/performance improvements. If including any bug fixes, mention the issue numbers associated with the bugs.
-
-* Once you have submitted the pull request, three things will automatically occur:
-
-  - The **test suite** will automatically run on [GitHub actions](https://github.com/XanaduAI/strawberryfields/actions?query=workflow%3ATests)
-    to ensure that the all tests continue to pass.
-  - Once the test suite is finished, a **code coverage report** will be generated on
-    [Codecov](https://codecov.io/gh/XanaduAI/strawberryfields). This will calculate the percentage of Strawberry Fields
-    covered by the test suite, to ensure that all new code additions are adequately tested.
-  - Finally, the **code quality** is calculated by [Codacy](https://app.codacy.com/app/XanaduAI/strawberryfields/dashboard),
-    to ensure all new code additions adhere to our code quality standards.
-
-  Based on these reports, we may ask you to make small changes to your branch before merging the pull request into the master branch. Alternatively, you can also
-  [grant us permission to make changes to your pull request branch](https://help.github.com/articles/allowing-changes-to-a-pull-request-branch-created-from-a-fork/).
-
-## I've made a contribution! Now how do I claim my Xanadu Swag?
-
-* If you've contributed code to Strawberry Fields, we'll contact you shortly after merging your pull
-  request to organise delivery of your Xanadu Swag™.
-
-* If you've created a Strawberry Fields application, produced content using Strawberry Fields, or simply
-  written an awesome Strawberry Fields tutorial, and we have linked it to our Gallery, you are eligible for some
-  Xanadu Swag™. We will contact you to organise delivery of your swag.
-
-If you haven't heard back from us, don't panic! Here at Xanadu we are working on projects on the cutting edge of
-quantum technology, and sometimes get a little sidetracked. Simply send a reminder email to support@xanadu.ai regarding your
-swag, and we'll get back to you ASAP.
 
-:strawberry: Thank you for contributing to Strawberry Fields! :strawberry:
+Thank you for being part of Strawberry Fields!
 
 \- The Strawberry Fields team

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,5 +1,8 @@
 ### Before submitting
 
+We are not accepting Pull Requests for new features at this time. We welcome contributions for bug fixes,
+security patches, and documentation improvements only. Thank you for your understanding.
+
 Please complete the following checklist when submitting a PR:
 
 - [ ] All new features must include a unit test.

README.md

@@ -58,7 +58,7 @@
 
 ## Installation
 
-Strawberry Fields requires Python version 3.7, 3.8, 3.9, or 3.10. Installation of Strawberry Fields, as
+Strawberry Fields requires Python version 3.8, 3.9, or 3.10. Installation of Strawberry Fields, as
 well as all dependencies, can be done using pip:
 
 ```console
@@ -81,25 +81,15 @@ Next, read more about using Strawberry Fields with
 [photonic hardware](https://strawberryfields.ai/photonics/hardware/index.html), including code
 demonstrations and an overview of Xanadu's quantum photonic hardware.
 
-Developers can head to the
-[development guide](https://strawberryfields.readthedocs.io/en/stable/development/development_guide.html)
-to see how they can contribute to Strawberry Fields.
-
 
 ## Contributing to Strawberry Fields
 
-We welcome contributions — simply fork the Strawberry Fields repository, and then make a
-[pull request](https://help.github.com/articles/about-pull-requests/) containing your contribution.
-All contributors to Strawberry Fields will be listed as authors on the releases.
-
-We also encourage bug reports, suggestions for new features and enhancements, and even links to cool
-projects or applications built on Strawberry Fields.
+We are not accepting Pull Requests for new features at this time. We welcome contributions for bug fixes,
+security patches, and documentation improvements only. Thank you for your understanding.
 
 See our [contributions page](https://github.com/XanaduAI/strawberryfields/blob/master/.github/CONTRIBUTING.md)
 and [changelog](https://github.com/XanaduAI/strawberryfields/blob/master/.github/CHANGELOG.md)
-for more details, and then check out some of the Strawberry Fields
-[challenges](https://github.com/XanaduAI/strawberryfields/blob/master/.github/CHALLENGES.md)
-for some inspiration.
+for more details.
 
 
 ## Authors

doc/development/development_guide.rst

@@ -6,15 +6,15 @@ Dependencies
 
 Strawberry Fields requires the following libraries be installed:
 
-* `Python <http://python.org/>`_ >= 3.6
+* `Python <http://python.org/>`_ >= 3.8
 
 as well as the following Python packages:
 
 * `NumPy <http://numpy.org/>`_ >= 1.17.4
 * `SciPy <http://scipy.org/>`_ >= 1.0.0
 * `NetworkX <http://networkx.github.io/>`_ >= 2.0
-* `Blackbird <https://quantum-blackbird.readthedocs.io>`_ >= 0.2.0
-* `The Walrus <https://the-walrus.readthedocs.io>`_ >= 0.7.0
+* `Blackbird <https://quantum-blackbird.readthedocs.io>`_ >= 0.3.0
+* `The Walrus <https://the-walrus.readthedocs.io>`_ >= 0.18.0
 * `toml <https://pypi.org/project/toml/>`_
 
 If you currently do not have Python 3 installed, we recommend
@@ -250,6 +250,11 @@ from within the top-level directory. To then build the HTML documentation, run
 
 The documentation can be found in the :file:`doc/_build/html/` directory.
 
+Contributing to Strawberry Fields
+---------------------------------
+
+We are not accepting Pull Requests for new features at this time. We welcome contributions for bug fixes,
+security patches, and documentation improvements only. Thank you for your understanding.
 
 Adding a new module to the docs
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -293,7 +298,7 @@ a module:
 
 
 Submitting a pull request
--------------------------
+^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Before submitting a pull request, please make sure the following is done:
 

doc/development/research.rst

@@ -22,10 +22,7 @@ Strawberry Fields is an open-source library, with the up-to-date code available
 - **Source Code:** https://github.com/XanaduAI/strawberryfields
 - **Issue Tracker:** https://github.com/XanaduAI/strawberryfields/issues
 
-We welcome contributions - simply fork the Strawberry Fields repository, and then make a
-`pull request <https://help.github.com/articles/about-pull-requests/>`_ containing your contribution.  All contributers to Strawberry Fields will be listed as authors on the releases.
-
-We also encourage bug reports, suggestions for new features and enhancements, and even links to cool projects or applications built on Strawberry Fields.
+We are not accepting Pull Requests for new features at this time. We welcome contributions for bug fixes, security patches, and documentation improvements only. Thank you for your understanding.
 
 Support
 --------