Equation numbering w/o labels

[agerlach]

Is is possible to add equation numbers for all $$...$$ equations w/o adding a label?

For example, I would like the following to still number the equations 1, 2, 3 respectively. Currently a is number 1, b is not numbered and c is numbered 3.

$$a$$ {#eq-a}

$$b$$

$$c$$ {#eq-c}

[eeholmes]

If you use $$ $$ format (display math), then to have equation numbers, you need to add {#eq-xyp} on every equation. It is just the nature of $$ $$.

[agerlach]

What other options is there outside of $$ $$ ?

…

On Fri, Jan 27, 2023 at 7:04 PM Eli Holmes ***@***.***> wrote: If you use $$ $$ format (display math), then to have equation numbers, you need to add {#eq-xyp} on every equation. It is just the nature of $$ $$. — Reply to this email directly, view it on GitHub <#4132 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAESK7M7VOY6BJ6CNPJYMSTWURPABANCNFSM6AAAAAAUJBSYY4> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[eeholmes]

You can use what is called LaTeX equation environments. However, learning LaTeX is probably overkill. But here is how you do it:

\begin{equation}\tag{1}\label{eq-a}
a
\end{equation}

\begin{equation*}
b
\end{equation*}

\begin{equation}\tag{3}\label{eq-b}
c
\end{equation}

You have to set fixed tags, not autonumbered, because you are telling it to skip ahead to eq 3 essentially.

Note for html you have to turn on equation numbering if you use the math environment. For PDF output, you don't have to do this.

To do this, create a file called mathjax.html (say) with this:

<script>
  MathJax = {
    tex: {
      tags: 'ams'  // should be 'ams', 'none', or 'all'
    }
  };
</script>

And add this to your html header with

---
title: "test"
format:
  html:
    include-in-header: mathjax.html
---

[baptiste]

One could probably write a lua filter that would detect if an equation is unlabelled, and add an automatic label. This filter might be a good starting point (I wasn't able to adapt it in my brief attempt).

[eeholmes]

@baptiste Do you know how to tell Quarto to use a modified equations.lua instead of this one? I know how to replace templates and template-partials but not lua filters.

[baptiste]

Not sure, sorry; usually filters just act independently one after the other, but here there's probably a risk of making incompatible/duplicated changes to the AST, I guess.

[jtlandis]

I wanted to do the same thing as @agerlach. Check out the quarto filter I made which is adapted from the resource @baptiste found.

It loosely works, but please let me know if you find any bugs