Enabling math markup

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We've always used Latex for this, but the installation can be complicated and it requires over a GB (yes a Gigabyte!) of packages to be installed that we don't use for anything else. But now client side rendering is possible, or server-side via the new Mathoid node.js service both of which are vastly preferable. See MW:Extension:Math for more detail about installation options. For a fully client-side rendering solution with no server-side installation at all use the settings shown in install a new server.

Enabling math markup Organic Design procedure

As of MediaWiki version 1.18 the math rendering has been put into the Math extension. See MW:Manual:Math for more details. To download the latest version of the extensions, use:

git clone https://gerrit.wikimedia.org/r/p/mediawiki/extensions/Math.git

Note that as of MediaWiki 1.19, the extension repository has become out of sync with the codebase and a specific version needs to be used which you can download from [1].

Build the texvc binary

Enabling math markup requires latex, dvips, gs, and convert. OCaml 3.06 or later from caml.inria.fr is required to compile texvc. On Debian-based systems the requirements can be installed with the following packages:

apt-get install dvipng cjk-latex ocaml

• Run make from within the MediaWiki's math directory to build the texvc binary on your system.
• Make sure the directories tmp and math under 'images' exist and are writable.
• Note: on Debian 7 we also required the texlive-latex-extra package.

Example

The following maths code:

<math>
e^x = \sum_{n = 0}^{\infty} {x^n \over n!} = 1 + x + {x^2 \over 2!} + {x^3 \over 3!} + {x^4 \over 4!} + \cdots
</math>

Should give the following output:

[math]e^x = \sum_{n = 0}^{\infty} {x^n \over n!} = 1 + x + {x^2 \over 2!} + {x^3 \over 3!} + {x^4 \over 4!} + \cdots[/math]

Nginx

After we changed over from Apache to Nginx I spent many hours trying to figure out why the texvc binary wouldn't produce the PNG file. The binary was being executed properly by shell_exec in MathTexvc.php, but for some reason would not build the image.

I couldn't find anything logged about a problem anywhere, and there were no differences in PHP configuration that I could find. I tried adjusting render.ml to leave the temporary files so I could analyse those (by removing the lines deleting then from the unlink_all function then running name clean and make to rebuild the texvc binary, but it wouldn't produce any of the files except the .tex one.

The only working solution I could come up with was to run the texvc as root using sudo by changing line 123 of MathTexvc.php as follows:

$contents = wfShellExec( "sudo $cmd" );

To allow the web-server to have sudo access without compromising security the following line can be added to the sudoers file using visudo.

www-data ALL=NOPASSWD: /path/to/wiki/extensions/Math/math/texvc

Update: On my most recent server installation, math wasn't rendering, and the server was delivering messages about a security problem whenever math formulas tried to render. I didn't need to modify any files, as texvc was already being called as root, so I just added the binary path to the sudoers file and it worked.

See also

• MW:Manual:Math
• MW:Extension:Math
• MW:Manual:Enable TeX
• MW:Manual:Running MediaWiki on Debian GNU/Linux#TeX_Support
• MW:Manual:Troubleshooting math display errors
• There was a problem extracting the database on 13/11 due to duplicate entries in the math table, see 13 November 2006.