Add try-qutip link and description.

_includes/navbar.html

@@ -19,6 +19,7 @@
         <li><a href="/qutip-tutorials/">Tutorials</a></li>
         <li><a href="/qutip-benchmark/">Benchmarks</a></li>
         <li><a href="/qutip-virtual-lab.html">QuTiP Virtual Lab</a></li>
+        <li><a href="/try-qutip.html">Try QuTiP</a></li>
         <li><a href="/features.html">Features</a></li>
         <li><a href="/citing.html">Citing</a></li>
       </ul>

_layouts/default.html

@@ -69,6 +69,7 @@ <h2>Quantum Toolbox in Python</h2>
         <li><a href="/qutip-tutorials/">Tutorials</a></li>
         <li><a href="/qutip-benchmark/">Benchmarks</a></li>
         <li><a href="/qutip-virtual-lab.html">QuTiP Virtual Lab</a></li>
+        <li><a href="/try-qutip.html">Try QuTiP</a></li>
         <li><a href="/features.html">Features</a></li>
         <li><a href="/citing.html">Citing</a></li>
       </ul>

try-qutip.md

@@ -0,0 +1,116 @@
+---
+title: Trying QuTiP in the Browser
+---
+
+# Trying QuTiP in the Browser
+
+QuTiP is now available in the browser!
+
+You can open it by clicking on the button below:
+
+<a class="btn btn-primary" href="/try-qutip/" role="button">Try QuTiP</a>
+
+The button opens a JupyterLite notebook server with the qutip package
+preinstalled. It runs entirely in your browser and includes copies of the
+<a href="/qutip-tutorials/">QuTiP tutorials</a> for you to explore. There is
+no server.
+
+Once JupterLite loads, you'll find the tutorials in the file browser on
+the left. If you click on a tutorial notebook, you'll need to select the
+XPython kernel (there is only one option) and then the notebook will open.
+The first imports will be slightly slow, but after that the performance
+should be similar to that of running QuTiP locally.
+
+<div class="alert alert-warning" role="alert">
+Running QuTiP this way relies on a complex set of underlying layers of
+software that are still maturing. You can read about some of the
+caveats and a description of how it was built below.
+</div>
+
+Contents:
+
+ - What's installed
+ - Caveats
+ - Contributing
+ - How the try-qutip site is built
+
+
+## What's installed
+
+Currently installed packages include:
+
+ - qutip (5.1.1)
+ - qutip-qip (0.4.0)
+ - qutip-qtrl (0.1.5)
+ - numpy (2.2.4)
+ - scipy (1.14.1)
+ - matplotlib (3.10.1)
+ - python (3.13.1)
+
+
+## Caveats
+
+Most QuTiP features already work. These are the known limitations:
+
+ - A recent version of Firefox or Chrome is required.
+ - Cython is not yet available so QobjEvo objects cannot currently
+   be usefully compiled.
+ - You can save notebooks but, they are <em>stored in your web browser's
+   internal storage and might be lost if, for example, the browser cache
+   is cleared. If you do create notebooks you'd like to keep, please
+   use the download button to save them.</em>
+ - Notebooks are slow to start, but performance is not too bad after that.
+
+Specific known issues are listed in [try-qutip's GitHub issues](https://github.com/qutip/try-qutip/issues/).
+Further issues and bugs may be reported there.
+
+
+## Contributing
+
+If you encounter bugs with QuTiP in the browser that aren't listed in the
+caveats above, you are welcome to open issues in the
+[try-qutip GitHub repository](https://github.com/qutip/try-qutip/).
+
+If you know a way to address any of the caveats above, please let us
+know by open an issue or pull request in the
+[try-qutip GitHub repository](https://github.com/qutip/try-qutip/).
+
+If you find bugs in a specific tutorial, or would like to add a new tutorial
+or improve an existing one, please see the contributing section at the bottom
+of the [tutorials page](/qutip-tutorials/).
+
+If you have general questions about how to use QuTiP, email the
+[QuTiP mailing list](https://groups.google.com/group/qutip).
+
+
+## How the try-qutip site is built
+
+The try-qutip site contains JupyterLite with QuTiP pre-installed.
+
+[JupyterLite](https://github.com/jupyterlite/jupyterlite) is a
+version of [JupyterLab](https://github.com/jupyterlab/jupyterlab)
+that has been modified work run in the browser as a
+[Service Worker](https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API).
+A service worker acts like a web server that runs inside your browser and in this
+case plays the role of the Jupyter server that would otherwise need to be run locally.
+
+Running this Jupyter server in the browser means running Python and packages
+such as numpy, SciPy and matplotlib in the browser too. To do that, all
+of these packages need to be recompiled to
+[WebAssembly (aka WASM)](https://webassembly.org/) and for
+that one needs a suitable compiler, in this case,
+[Emscripten](https://emscripten.org).
+
+Lastly, we need to compile QuTiP itself. The amazing team at
+[QuantStack](https://quantstack.net/) are building
+[emscripten-forge](https://beta.mamba.pm/channels/emscripten-forge/packages/?tab=packages)
+which is like [conda-forge](https://conda-forge.org/) but for building packages
+for WebAssembly.
+
+With the help of Wolf and Martin from QuantStack, we created a
+[QuTiP package on emscripten-forge](https://beta.mamba.pm/channels/emscripten-forge/packages/qutip).
+The recipe for building the package can be found in the
+[emscripten-forge/recipes](https://github.com/emscripten-forge/recipes) repository.
+
+An additional big thank you to Thorsten Beier from QuantStack for fixing
+numerous small niggles and thus allowing QuTiP 5 to deployed to try-qutip.