Recommendations mentioned in How to hide one specific cell (input or output) in IPython Notebook? don't work.
On Windows I do the following
jupyter nbconvert a.ipynb --TagRemovePreprocessor.remove_cell_tags="{'remove_cell'}"
but get an error
traitlets.traitlets.TraitError: The 'remove_cell_tags' trait of a TagRemovePreprocessor instance must be a set, but a value of type 'unicode' (i.e. u"{'remove_cell'}") was specified.
I also tried '{"remove_cell"}'
I am using nbconvert 5.4.0
Any ideas how to do this?
You need to enable the TagRemovePreprocessor before you call it.
The code below shows how to enable it and how to enclose your tags as a list so you can exclude more than one tag if you wish. To exclude a single tag, just put one element in the list eg ['remove_cell'].
The parameter --to html is not required if you are converting to html (as html is the default). If you want to convert to python, for example, change --to html to --to python
jupyter nbconvert a.ipynb --TagRemovePreprocessor.enabled=True --TagRemovePreprocessor.remove_cell_tags="['remove_cell', 'other_tag_to_remove']" --to html
Note that the TagRemovePreprocessor is only available in nbconvert 5.3 and above: https://nbconvert.readthedocs.io/en/latest/changelog.html?highlight=TagRemovePreprocessor
Needs some extra quoting to work:
--TagRemovePreprocessor.remove_cell_tags={\"remove_cell\"}.
However beware of an ongoing issue with noteboot to notebook conversion - it seems like in this case preprocessors, including tag removal, do not run. See more in this SO question:
jupyter nbconvert --to notebook not excluding raw cells
Update: Not tested on windows, just on Linux
Question
How can I setup a MathJax "preamble" for use in IPython (or Jupyter) notebooks for repeated use in a way that is convenient for others to read my documents (on http://nbviewer.org) and that works for LaTeX/PDF generation?
Background
I would like to use IPython (now Jupyter) notebooks for documents that I later convert to PDF via LaTeX (using ipython nbconvert). The problem is how to include a bunch of macro definitions that I use in almost every document. Something like:
\newcommand{\vect}[1]{\vec{#1}}
\newcommand{\abs}[1]{\lvert#1\rvert}
\DeclareMathOperator{\erf}{erf}
etc. As far as the notebooks is concerned, one unsatisfactory solution is to simply include these in a markdown cell at the top of the notebook, embeded between two dollar signs $$ so it is interpreted as math. If this is done after some introductory text, then it does not even affect the output.
The problem is that, when converting to LaTeX (for PDF export), these commands are embedded in a math environment in the LaTeX file. This has several problems:
Commands like \DeclareMathOperator must come in the LaTeX document preamble.
Command definitions are local to the equation and not available later in the document. (This can be overcome by using \gdef or \global\def but then one must trick MathJax into recognising these commands with something like \let\gdef{\def} which is somehow hidden from LaTeX. Any way I have found of making this work amounts to an ugly hack.)
Sometimes commands are already defined in LaTeX and need to have \renewcommand (not supported by MathJax, but again can be provided by \let\renewcommand\newcommand etc. which seems reasonable to me since MathJax can't have some idea of what preamble might be used for the final LaTeX file).
Probably the solution is to provide a set of macros to MathJax by adding code like (not sure the equivalent of \DeclareMathOperator here...)
<script type="text/x-mathjax-config">
MathJax.Hub.Config({
TeX: {
Macros: {
vect: ["{\\vec #1}",1],
abs: ["{\\lvert #1 \\rvert}",1]
}
}
});
</script>
to a custom.js file and then providing a LaTeX package for inclusion when converting to PDF. The problem I have with this approach is: How to distribute the custom.js file and LaTeX style file for others (collaborators and viewers) to use?
I want collaborators to be able to edit and read my documents without having to install custom extensions in their global configuration. To be specifiec, I am fine with requiring them to run a command like python setup.py configure once they download/checkout my code which does local modifications to the project like populating ipython_notebook_config.py files in all directories containing notebooks, but am not happy installing extensions, or modifying their personal global custom.js file.
My stumbling block here is that I don't know how to add contributions from a local custom.js file to the notebook chain, and suspect that this might violate a security policy.
The best solution would not require any action on my collaborator's part.
I want my notebooks to work on http://nbviewer.org, and for people to be able to download the notebook and produce a PDF. (I think this rules out the possibility of using custom.js hacks and a distributed *.sty file, but am not certain.)
I would prefer to be able to simply start a new notebook and then start writing without having to insert a bunch of boilerplate code at the start of each notebook, though would be amenable to having a simple way of automating this process using an notebook extension or some hooks in python_notebook_config.py.
References
The following posts address some of these issues, but fall short on most fronts:
usepackage and making macros in ipython notebook
Physics bra-ket symbols in IPython (specifically this answer notes related difficulties)
How do I get MathJax to enable the mhchem extension in ipython notebook
Discussions about (potential) problems with the pandoc production of LaTeX files from IPython notebooks:
Getting some problems with pandoc and mathjax
\newcommand environment when convert from markdown to pandoc
Pandoc IPython notebook loses some Mathjax
General discussion of math in notebooks:
How to write LaTeX in IPython Notebook?
I think you can solve some of your problems, but not all.
First, the stumbling block. I believe (though I might be wrong) that nbviewer doesn't look at anything but the notebook itself. For example, I don't see how it could run an ipython_notebook_config.py stored alongside your notebook. So that rules out that line of thought, meaning that I think you'll have to bite the bullet and add boilerplate to every notebook. But you might at least be able to minimize the boilerplate. In that vein:
You could maintain your custom.js (probably under a more descriptive name) on github or whatever, and then add one line of boilerplate to all your notebooks to load that script from the URL. You would still need boilerplate, but it would be a lot shorter.
Once you have executed the code cell containing the javascript, it is saved in the notebook, which means that it will automatically happen the next time the browser loads it, even before the code cell is executed. So unless nbviewer prevents the javascript's execution, it should work just fine. This would also make things work nicely for collaborators, since they wouldn't have to download additional files.
As for your own style file, I suspect that anyone sophisticated enough to install ipython and latex, download your notebook, and run nbconvert on it would also be sophisticated enough to download the .sty file. Anyway, I don't see any way around the need to do that...
After investigating, I've found mathjax can do this. But when I write some example in my markdown file, it doesn't show the correct equations:
I have added this in the head of markdown file:
<script type="text/javascript" src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=default"></script>
And type the mathjax statement:
\(E=mc^2\)，$$x_{1,2} = \frac{-b \pm \sqrt{b^2-4ac}}{2b}.$$
But github shows nothing for the math symbols! Please help me, thanks!
Tell me how to show math symbols in github markdown pages.
But github show nothing for the math symbols! please help me, thanks!
GitHub markdown parsing is performed by the SunDown (ex libUpSkirt) library.
The motto of the library is "Standards compliant, fast, secure markdown processing library in C". The important word being "secure" there, considering your question :).
Indeed, allowing javascript to be executed would be a bit off of the MarkDown standard text-to-HTML contract.
Moreover, everything that looks like a HTML tag is either escaped or stripped out.
Tell me how to show math symbols in general github markdown.
Your best bet would be to find a website similar to yuml.me which can generate on-the-fly images from by parsing the provided URL querystring.
Update
I've found some sites providing users with such service: codedogs.com (no longer seems to support embedding) or iTex2Img.
You may want to try them out. Of course, others may exist and some Google-fu will help you find them.
given the following markdown syntax
it will display the following image
Note: In order for the image to be properly displayed, you'll have to ensure the querystring part of the url is percent encoded. You can easily find online tools to help you with that task, such as www.url-encode-decode.com
Markdown supports inline HTML. Inline HTML can be used for both quick and simple inline equations and, with and external tool, more complex rendering.
Quick and Simple Inline
For quick and simple inline items use HTML ampersand entity codes. An example that combines this idea with subscript text in markdown is: hθ(x) = θo x + θ1x, the code for which follows.
h<sub>θ</sub>(x) = θ<sub>o</sub> x + θ<sub>1</sub>x
HTML ampersand entity codes for common math symbols can be found here. Codes for Greek letters here. An extensive list html entity codes to Unicode characters can be found here.
While this approach has limitations it works in practically all markdown and does not require any external libraries.
Complex Scalable Inline Rendering with LaTeX and Codecogs
If your needs are greater use an external LaTeX renderer like CodeCogs. Create an equation with CodeCogs editor. Choose svg for rendering and HTML for the embed code. Svg renders well on resize. HTML allows LaTeX to be easily read when you are looking at the source. Copy the embed code from the bottom of the page and paste it into your markdown.
<img src="https://latex.codecogs.com/svg.latex?\Large&space;x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}" title="\Large x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}" />
Expressed in markdown becomes
This combines this answer and this answer.
GitHub support only somtimes worked using the above raw html syntax for readable LaTeX for me. If the above does not work for you another option is to instead choose URL Encoded rendering and use that output to manually create a link like:
This manually incorporates LaTex in the alt image text and uses an encoded URL for rendering on GitHub.
Multi-line Rendering
If you need multi-line rendering check out this answer.
It ’s 2020 now, let me summarize the progress of the mathematical formula rendering support of source code repository hosts.
GitHub & Bitbucket
GitHub and Bitbucket still do not support the rendering of mathematical formulas, whether it is the default delimiters or other.
Bitbucket Cloud / BCLOUD-11192 -- Add LaTeX Support in MarkDown Documents (BB-12552)
GitHub / markup -- Rendering math equations
GitHub / markup -- Support latex
GitHub Community Forum -- [FEATURE REQUEST] LaTeX Math in Markdown
talk.commonmark.org -- Can math formula added to the markdown
GitHub has hardly made any substantial progress in recent years.
GitLab
GitLab is already supported, but not the most common way. It uses its own delimiter.
This math is inline $`a^2+b^2=c^2`$.
This is on a separate line
```math
a^2+b^2=c^2
```
GitLab Flavored Markdown -- Math
Who supports the universal delimiters?
A Markdown parser used by Hugo
Other ways to render
Use web api to render according to A hack for showing LaTeX formulas in GitHub markdown, you can even write jupyter notebook.
readme2tex
It is officially supported since May 2022:
Render mathematical expressions in Markdown
You can now use LaTeX style syntax to render math expressions within Markdown inline (using $ delimiters) or in blocks (using $$ delimiters).
Writing expressions as blocks
To add math as a multiline block displayed separately from surrounding text, start a new line and delimit the expression with two dollar symbols $$.
**The Cauchy-Schwarz Inequality**
$$\left( \sum_{k=1}^n a_k b_k \right)^2 \leq \left( \sum_{k=1}^n a_k^2 \right) \left( \sum_{k=1}^n b_k^2 \right)$$
Writing inline expressions
To include a math expression inline with your text, delimit the expression with a dollar symbol $.
This sentence uses `$` delimiters to show math inline: $\sqrt{3x-1}+(1+x)^2$
GitHub's math rendering capability uses MathJax; an open source, JavaScript-based display engine.
MathJax supports a wide range of LaTeX macros and a number of useful accessibility extensions.
For more information, see the MathJax documentation and the MathJax Accessibility Extensions documentation.
Some users have previously used a workaround to generate images of mathematical expressions through API requests.
Images generated this way will remain viewable, but this technique will no longer work.
Going forward, expressions should be written directly in Markdown using LaTeX syntax as described above.
For more information about authoring content with advanced formatting, see Working with advanced formatting in the GitHub documentation.
This is still beta, and criticised.
See "Math on GitHub: The Good, the Bad and the Ugly" from Nico Schlömer.
The syntax introduces:
Competing Markdown and math renderer
A math block hard to interpret
As noted by brc-dd in the comments:
June 2022:
Fenced block syntax for mathematical expressions
Users can now delineate mathematical expressions using ```math fenced code block syntax in addition to the already supported delimiters.
Two dollar sign $$ delimiters are not required if this method is used.
**Here is some math!**
```math
\sqrt{3}
.```
becomes:
Read more about working with advanced formatting.
Another possibility is to rely on GitHub's own notebook renderer. This even works right here in SO.
To render x_{1,2} = \frac{-b \pm \sqrt{b^2-4ac}}{2b} use the following HTML img tag:
<img src="https://render.githubusercontent.com/render/math?math=x_{1,2} = \frac{-b \pm \sqrt{b^2-4ac}}{2b}">
Live Demo:
What's great about this approach is that you can edit your formula directly in Markdown and the preview will update accordingly.
You can try it out by editing this answer. (Just throw away your edits if they don't add to the answer ;))
Source: https://gist.github.com/a-rodin/fef3f543412d6e1ec5b6cf55bf197d7b
One other work-around is to use jupyter notebooks and use the markdown mode in cells to render equations.
Basic stuff seems to work perfectly, like centered equations
\begin{equation}
...
\end{equation}
or inline equations
$ \sum_{\forall i}{x_i^{2}} $
Although, one of the functions that I really wanted did not render at all in github was \mbox{}, which was a bummer. But, all in all this has been the most successful way of rendering equations on github.
If just wanted to show math in the browser for yourself, you could try the Chrome extension GitHub with MathJax. It's quite convenient.
While GitHub won't interpret the MathJax formulas, you can automatically generate a new Markdown document with the formulae replaced by images.
I suggest you look at the GitHub app TeXify:
GitHub App that looks in your pushes for files with extension *.tex.md and renders it's TeX expressions as SVG images
How it works (from the source repository):
Whenever you push TeXify will run and seach for *.tex.md files in your last commit. For each one of those it'll run readme2tex which will take LaTeX expressions enclosed between dollar signs, convert it to plain SVG images, and then save the output into a .md extension file (That means that a file named README.tex.md will be processed and the output will be saved as README.md). After that, the output file and the new SVG images are then commited and pushed back to your repo.
I use the below mentioned process to convert equations to markdown. This works very well for me. Its very simple!!
Let's say, I want to represent matrix multiplication equation
Step 1:
Get the script for your formulae from here - https://csrgxtu.github.io/2015/03/20/Writing-Mathematic-Fomulars-in-Markdown/
My example: I wanted to represent Z(i,j)=X(i,k) * Y(k, j); k=1 to n into a summation formulae.
Referencing the website, the script needed was => Z_i_j=\sum_{k=1}^{10} X_i_k * Y_k_j
Step 2:
Use URL encoder - https://www.urlencoder.org/ to convert the script to a valid url
My example:
Step 3:
Use this website to generate the image by copy-pasting the output from Step 2 in the "eq" request parameter - http://www.sciweavers.org/tex2img.php?eq=<b><i>paste-output-here</i></b>&bc=White&fc=Black&im=jpg&fs=12&ff=arev&edit=
- My example:
http://www.sciweavers.org/tex2img.php?eq=Z_i_j=\sum_{k=1}^{10}%20X_i_k%20*%20Y_k_j&bc=White&fc=Black&im=jpg&fs=12&ff=arev&edit=
Step 4:
Reference image using markdown syntax - 
- Copy this in your markdown and you are good to go:
Image below is the output of markdown. Hurray!!
I just released a little Chrome extension, xhub, that lets you use LaTeX math (and more) in GitHub pages.
Pros:
You don't have to set up anything in your repo, just use math in your Markdown (sytax from GitLab):
Some display math:
```math
e^{i\pi} + 1 = 0
```
and some inline math, $`a^2 + b^2 = c^2`$.
It works on light and dark backgrounds alike.
You can copy-and-paste the math
Cons:
You have to install a browser extension once.
There is good solution for your problem - use TeXify github plugin (mentioned by Tom Hale answer - but I developed his answer in given link below) - more details about this github plugin and explanation why this is good approach you can find in that answer.
I used the following in the head of mark down file
<script type="text/javascript" async
src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.2/MathJax.js?
config=TeX-MML-AM_CHTML"
</script>
Then typed the following mathjax statement
$$x_{1,2} = \frac{-b \pm \sqrt{b^2-4ac}}{2b}.$$
It worked for me
A "quick and dirty" solution is to maintain a standard .md file using standard TeX equations, e.g. _README.md.
When you are satisfied, pass the entire file through Pandoc to convert from standard Markdown to Markdown (Github flavour), and copy the output to README.md.
You can do this online for a quick turnaround, or install/configure Pandoc locally.
Mathcha is a sophisticated mathematics editor, but it can be used to render individual equations and save them as pure html, which you can then add to your documents as inline html OR you can save as SVG and insert as an image. https://www.mathcha.io/
You can embed your LaTeX in an image URL rendered by render.githubusercontent.com such as this one:
<img src="https://render.githubusercontent.com/render/math?math={x + y}">
which will render like this:
Which you'll notice is missing the + sign. To fix that you can URL encode the plus sigh as %2b or URL encode the entire equation, which will render like so:
Unfortunately this will always render in black, so you'll want to use this GitHub specific trick to render white text for users using dark mode and black text to users using light mode, by including the equation once with the #gh-light-mode-only and again with the LaTeX comand \color{white} and the #gh-dark-mode-only tag:
<img src="https://render.githubusercontent.com/render/math?math={x - y}#gh-light-mode-only">
<img src="https://render.githubusercontent.com/render/math?math={\color{white}x - y}#gh-dark-mode-only">
which will display this to light mode users:
and display this to dark mode users:
Now since May 2022, Github accept LATEX directly into Markdown, the only thing to do is to put the LATEX code inside $$$$ on your markdown
One more thing, you can colorize the math using the {\color{nameColor}text} on markdown
$${\color{red}\sum\limits_{\color{lightblue}i=0}^{\color{orange}n} {\color{pink}i}} = \frac{\color{pink}n!}{\color{lightblue}k!(n-k)!}$$
Example in a picture:
$$\sum\limits_{i=0}^n i^2$$ create the sum:
Regarding tex→image conversion, the tool LaTeXiT produces much higher quality output. I believe it is standard in most TeX distributions but you can certainly find it online if you don't already have it. All you need to do is put it in the TeX, drag the image to your desktop, then drag from your desktop to an image hosting site (I use imgur).
TeXify is no longer working. Check my repo readme2tex-action on how to create Github actions.
Add action.yml file to your repo at .github/workflows/action.yml.
Change branch main name if it is necessary.