# Math support in Sphinx¶

New in version 0.5.

Since mathematical notation isn’t natively supported by HTML in any way, Sphinx supports math in documentation with several extensions.

The basic math support is contained in sphinx.ext.mathbase. Other math support extensions should, if possible, reuse that support too.

Note

mathbase is not meant to be added to the extensions config value, instead, use either sphinx.ext.imgmath or sphinx.ext.mathjax as described below.

The input language for mathematics is LaTeX markup. This is the de-facto standard for plain-text math notation and has the added advantage that no further translation is necessary when building LaTeX output.

Keep in mind that when you put math markup in Python docstrings read by autodoc, you either have to double all backslashes, or use Python raw strings (r"raw").

mathbase provides the following config values:

math_number_all

Set this option to True if you want all displayed math to be numbered. The default is False.

mathbase defines these new markup elements:

:math:

Role for inline math. Use like this:

Since Pythagoras, we know that :math:a^2 + b^2 = c^2.

.. math::

Directive for displayed math (math that takes the whole line for itself).

The directive supports multiple equations, which should be separated by a blank line:

.. math::

(a + b)^2 = a^2 + 2ab + b^2

(a - b)^2 = a^2 - 2ab + b^2


In addition, each single equation is set within a split environment, which means that you can have multiple aligned lines in an equation, aligned at & and separated by \\:

.. math::

(a + b)^2  &=  (a + b)(a + b) \\
&=  a^2 + 2ab + b^2


For more details, look into the documentation of the AmSMath LaTeX package.

When the math is only one line of text, it can also be given as a directive argument:

.. math:: (a + b)^2 = a^2 + 2ab + b^2


Normally, equations are not numbered. If you want your equation to get a number, use the label option. When given, it selects an internal label for the equation, by which it can be cross-referenced, and causes an equation number to be issued. See eq for an example. The numbering style depends on the output format.

There is also an option nowrap that prevents any wrapping of the given math in a math environment. When you give this option, you must make sure yourself that the math is properly set up. For example:

.. math::
:nowrap:

\begin{eqnarray}
y    & = & ax^2 + bx + c \\
f(x) & = & x^2 + 2xy + y^2
\end{eqnarray}

:eq:

Role for cross-referencing equations via their label. This currently works only within the same document. Example:

.. math:: e^{i\pi} + 1 = 0
:label: euler

Euler's identity, equation :eq:euler, was elected one of the most
beautiful mathematical formulas.


## sphinx.ext.imgmath – Render math as images¶

New in version 1.4.

This extension renders math via LaTeX and dvipng or dvisvgm into PNG or SVG images. This of course means that the computer where the docs are built must have both programs available.

There are various config values you can set to influence how the images are built:

imgmath_image_format

The output image format. The default is 'png'. It should be either 'png' or 'svg'.

imgmath_latex

The command name with which to invoke LaTeX. The default is 'latex'; you may need to set this to a full path if latex is not in the executable search path.

Since this setting is not portable from system to system, it is normally not useful to set it in conf.py; rather, giving it on the sphinx-build command line via the -D option should be preferable, like this:

sphinx-build -b html -D imgmath_latex=C:\tex\latex.exe . _build/html


This value should only contain the path to the latex executable, not further arguments; use imgmath_latex_args for that purpose.

imgmath_dvipng

The command name with which to invoke dvipng. The default is 'dvipng'; you may need to set this to a full path if dvipng is not in the executable search path. This option is only used when imgmath_image_format is set to 'png'.

imgmath_dvisvgm

The command name with which to invoke dvisvgm. The default is 'dvisvgm'; you may need to set this to a full path if dvisvgm is not in the executable search path. This option is only used when imgmath_image_format is 'svg'.

imgmath_latex_args

Additional arguments to give to latex, as a list. The default is an empty list.

imgmath_latex_preamble

Additional LaTeX code to put into the preamble of the short LaTeX files that are used to translate the math snippets. This is empty by default. Use it e.g. to add more packages whose commands you want to use in the math.

imgmath_dvipng_args

Additional arguments to give to dvipng, as a list. The default value is ['-gamma', '1.5', '-D', '110', '-bg', 'Transparent'] which makes the image a bit darker and larger then it is by default, and produces PNGs with a transparent background. This option is used only when imgmath_image_format is 'png'.

imgmath_dvisvgm_args

Additional arguments to give to dvisvgm, as a list. The default value is ['--no-fonts']. This option is used only when imgmath_image_format is 'svg'.

imgmath_use_preview

dvipng has the ability to determine the “depth” of the rendered text: for example, when typesetting a fraction inline, the baseline of surrounding text should not be flush with the bottom of the image, rather the image should extend a bit below the baseline. This is what TeX calls “depth”. When this is enabled, the images put into the HTML document will get a vertical-align style that correctly aligns the baselines.

Unfortunately, this only works when the preview-latex package is installed. Therefore, the default for this option is False.

Currently this option is only used when imgmath_image_format is 'png'.

imgmath_add_tooltips

Default: True. If false, do not add the LaTeX code as an “alt” attribute for math images.

imgmath_font_size

The font size (in pt) of the displayed math. The default value is 12. It must be a positive integer.

## sphinx.ext.mathjax – Render math via JavaScript¶

New in version 1.1.

This extension puts math as-is into the HTML files. The JavaScript package MathJax is then loaded and transforms the LaTeX markup to readable math live in the browser.

Because MathJax (and the necessary fonts) is very large, it is not included in Sphinx.

mathjax_path

The path to the JavaScript file to include in the HTML files in order to load MathJax.

The default is the https:// URL that loads the JS files from the cdnjs Content Delivery Network. See the MathJax Getting Started page for details. If you want MathJax to be available offline, you have to download it and set this value to a different path.

The path can be absolute or relative; if it is relative, it is relative to the _static directory of the built docs.

For example, if you put MathJax into the static path of the Sphinx docs, this value would be MathJax/MathJax.js. If you host more than one Sphinx documentation set on one server, it is advisable to install MathJax in a shared location.

You can also give a full http:// URL different from the CDN URL.

## sphinx.ext.jsmath – Render math via JavaScript¶

This extension works just as the MathJax extension does, but uses the older package jsMath. It provides this config value:

jsmath_path

The path to the JavaScript file to include in the HTML files in order to load JSMath. There is no default.

The path can be absolute or relative; if it is relative, it is relative to the _static directory of the built docs.

For example, if you put JSMath into the static path of the Sphinx docs, this value would be jsMath/easy/load.js. If you host more than one Sphinx documentation set on one server, it is advisable to install jsMath in a shared location.