Minor updates to README.md (#2158)

Svetlana Karslioglu · web-flow · commit dbeb11e33313 · 2022-12-16T15:03:04.000-08:00
* Minor updates to README.md

- Clarified that we want Python files rather than notebooks
- Added info about how to build a single tutorial.

* Update README.md

* Update README.md
diff --git a/README.md b/README.md
@@ -9,29 +9,46 @@ All the tutorials are now presented as sphinx style documentation at:
 
 # Contributing
 
-We use sphinx-gallery's [notebook styled examples](https://sphinx-gallery.github.io/stable/tutorials/index.html) to create the tutorials. Syntax is very simple. In essence, you write a slightly well formatted python file and it shows up as documentation page.
+We use sphinx-gallery's [notebook styled examples](https://sphinx-gallery.github.io/stable/tutorials/index.html) to create the tutorials. Syntax is very simple. In essence, you write a slightly well formatted Python file and it shows up as an HTML page. In addition, a Jupyter notebook is autogenerated and available to run in Google Colab.
 
-Here's how to create a new tutorial or recipe:
-1. Create a notebook styled python file. If you want it executed while inserted into documentation, save the file with suffix `tutorial` so that file name is `your_tutorial.py`.
-2. Put it in one of the beginner_source, intermediate_source, advanced_source based on the level. If it is a recipe, add to recipes_source.
-2. For Tutorials (except if it is a prototype feature), include it in the TOC tree at index.rst
+Here is how you can create a new tutorial (for a detailed description, see [CONTRIBUTING.md](./CONTRIBUTING.md)):
+
+1. Create a Python file. If you want it executed while inserted into documentation, save the file with the suffix `tutorial` so that the file name is `your_tutorial.py`.
+2. Put it in one of the `beginner_source`, `intermediate_source`, `advanced_source` directory based on the level of difficulty. If it is a recipe, add it to `recipes_source`. For tutorials demonstrating unstable prototype features, add to the `prototype_source`.
+2. For Tutorials (except if it is a prototype feature), include it in the `toctree` directive and create a `customcarditem` in [index.rst](./index.rst).
 3. For Tutorials (except if it is a prototype feature), create a thumbnail in the [index.rst file](https://github.com/pytorch/tutorials/blob/master/index.rst) using a command like `.. customcarditem:: beginner/your_tutorial.html`. For Recipes, create a thumbnail in the [recipes_index.rst](https://github.com/pytorch/tutorials/blob/master/recipes_source/recipes_index.rst)
 
-In case you prefer to write your tutorial in jupyter, you can use [this script](https://gist.github.com/chsasank/7218ca16f8d022e02a9c0deb94a310fe) to convert the notebook to python file. After conversion and addition to the project, please make sure the sections headings etc are in logical order.
+If you are starting off with a Jupyter notebook, you can use [this script](https://gist.github.com/chsasank/7218ca16f8d022e02a9c0deb94a310fe) to convert the notebook to Python file. After conversion and addition to the project, please make sure that section headings and other things are in logical order.
+
+## Building locally
 
-## Building
+The tutorial build is very large and requires a GPU. If your machine does not have a GPU device, you can preview your HTML build without actually downloading the data and running the tutorial code: 
 
-- Start with installing torch, torchvision, and your GPUs latest drivers. Install other requirements using `pip install -r requirements.txt`
+1. Install required dependencies by running: `pip install -r requirements.txt`.
 
-> If you want to use `virtualenv`, make your environment in a `venv` directory like: `virtualenv ./venv`, then `source ./venv/bin/activate`.
+> If you want to use `virtualenv`, in the root of the repo, run: `virtualenv venv`, then `source venv/bin/activate`.
 
-- Then you can build using `make docs`. This will download the data, execute the tutorials and build the documentation to `docs/` directory. This will take about 60-120 min for systems with GPUs. If you do not have a GPU installed on your system, then see next step.
+- If you have a GPU-powered laptop, you can build using `make docs`. This will download the data, execute the tutorials and build the documentation to `docs/` directory. This might take about 60-120 min for systems with GPUs. If you do not have a GPU installed on your system, then see next step.
 - You can skip the computationally intensive graph generation by running `make html-noplot` to build basic html documentation to `_build/html`. This way, you can quickly preview your tutorial.
 
-> If you get **ModuleNotFoundError: No module named 'pytorch_sphinx_theme' make: *** [html-noplot] Error 2** from /tutorials/src/pytorch-sphinx-theme or /venv/src/pytorch-sphinx-theme (while using virtualenv), run `python setup.py install`. 
+> If you get **ModuleNotFoundError: No module named 'pytorch_sphinx_theme' make: *** [html-noplot] Error 2** from /tutorials/src/pytorch-sphinx-theme or /venv/src/pytorch-sphinx-theme (while using virtualenv), run `python setup.py install`.
+
+## Building a single tutorial
+
+You can build a single tutorial by using the `GALLERY_PATTERN` environment variable. For example to run only `neural_style_transfer_tutorial.py`, run:
+
+```
+GALLERY_PATTERN="neural_style_transfer_tutorial.py" make html
+```
+or
+
+```
+GALLERY_PATTERN="neural_style_transfer_tutorial.py" sphinx-build . _build
+```
 
+The `GALLERY_PATTERN` variable respects regular expressions.
 
 ## About contributing to PyTorch Documentation and Tutorials
 * You can find information about contributing to PyTorch documentation in the 
 PyTorch Repo [README.md](https://github.com/pytorch/pytorch/blob/master/README.md) file. 
-* Additional information can be found in [PyTorch CONTRIBUTING.md](https://github.com/pytorch/pytorch/blob/master/CONTRIBUTING.md).
+* Additional information can be found in [PyTorch CONTRIBUTING.md](https://github.com/pytorch/pytorch/blob/master/CONTRIBUTING.md).
