LaTeX2Exp — transform LaTeX strings into R expressions

latex2exp is a new R package that parses and converts LaTeX math formulas into R’s plotmath expressions. Plotmath expressions are used to enter mathematical formulas and symbols to be rendered as text, axis labels, etc. throughout R’s plotting system. I find plotmath expressions to be quite opaque and fiddly; LaTeX is a de-facto standard for mathematical expressions, so this package might be useful to others as well. You can check it out on GitHub.



“Supported” LaTeX

Only a subset of LaTeX is supported, and not 100% correctly. Greek symbols (\alpha, \beta, etc.) and the usual operators (+, -, etc.) are supported. Additionally, the following symbols and operators should be supported:


Setting up a nice AucTeX environment on Mac OS X

Most people I know use TeXShop on Mac OS X. While it’s a pretty good TeX editor, I think Emacs is overall vastly superior. Of course, I’m rather biased since I already use Emacs for everything else… Perhaps this post will be useful to other Emacs-addicted astronomers.

In my setup, I use the AUCTeX package coupled with the Skim PDF viewer (if you’re not using Skim, download it, it’s brilliant!). One of the advantages of this combination is that Emacs and Skim can be kept in sync, like in the screenshot below.

Skim + Emacs/AUCTeX nirvana. Note that the current highlighted line in Skim corresponds to the cursor position in Emacs.
Skim + Emacs/AUCTeX nirvana. Note that the current highlighted line in Skim corresponds to the cursor position in Emacs.

I found it a bit difficult to set up the AUCTeX package with sensible defaults, so I’ll reproduce here my configuration in hopes that it will be useful to someone else.

The salient lines are the ones configuring latexmk and Skim. You should have latexmk installed if you are using the TeX Live distribution; Skim can be downloaded for free here. You can stick this script in your Emacs initialization file (see my dotemacs repository if you’d like to see my other Emacs configs). I shamelessly copied those lines from this Stack Overflow answer.

Two LaTeX gems: ShareLaTeX and latexdiff

Here are two really cool LaTeX tools every astronomer should enjoy.

ShareLaTeX is an online LaTeX writing tool. It’s great for collaboratively writing LaTeX documents of any size, and a life-saver when you don’t have access to your own laptop with a TeX installation on it — just grab a web browser, navigate to ShareLaTeX and write away, then grab the PDF product. (You can also chat with collaborators, browse revisions, and a bunch of other useful niceties.)

A sample ShareLaTeX project.
A sample ShareLaTeX project.

The folks behind ShareLaTeX generously announced today that they made their product open-source. Here is the GitHub page with their source code. It appears to be extremely easy to run your own local installation, if you so desire.

While working on a grant application (in the old, inefficient fashion: on a Dropbox shared folder) I wished there was some way to send “diffs” of my changes to the PDF to my collaborators, in order to save them the time to hunt for the changed word or sentence. Emery Berger’s blog directed me to the latexdiff tool, which I had somehow never heard about! It’s quite easy to install (if you use MacPorts, it’s a simple sudo port install latexdiff), and the resulting PDF diffs are nice and clear.

A sample latexdiff output.
A sample latexdiff output.