Replace MathJax with Katex. (#1362)

Co-authored-by: holly1238 <77758406+holly1238@users.noreply.github.com>

Author: sbrodehl

conf.py

@@ -55,8 +55,11 @@
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = ['sphinx.ext.mathjax', 'sphinx_copybutton',
-              'sphinx_gallery.gen_gallery']
+extensions = [
+    'sphinxcontrib.katex',
+    'sphinx_copybutton',
+    'sphinx_gallery.gen_gallery',
+]
 
 
 # -- Sphinx-gallery configuration --------------------------------------------
@@ -242,6 +245,18 @@
 
 
 def setup(app):
+    # NOTE: in Sphinx 1.8+ `html_css_files` is an official configuration value
+    # and can be moved outside of this function (and the setup(app) function
+    # can be deleted).
+    html_css_files = [
+        'https://cdn.jsdelivr.net/npm/katex@0.10.0-beta/dist/katex.min.css'
+    ]
+    # In Sphinx 1.8 it was renamed to `add_css_file`, 1.7 and prior it is
+    # `add_stylesheet` (deprecated in 1.8).
+    add_css = getattr(app, 'add_css_file', app.add_stylesheet)
+    for css_file in html_css_files:
+        add_css(css_file)
+
     # Custom CSS
     # app.add_stylesheet('css/pytorch_theme.css')
     # app.add_stylesheet('https://fonts.googleapis.com/css?family=Lato')

requirements.txt

@@ -23,6 +23,7 @@ ray[tune]
 
 ipython
 
+sphinxcontrib.katex
 # to run examples
 boto3
 pandas