This document provides some solutions and workarounds to try when things go wrong.
There are many ways that the processing of LaTeX snippets can fail.
The ‘tinytex’ documentation includes some advice to help with debugging LaTeX errors.
One way to explore the problem is to author() the LaTeX snippet, save the result into a .tex file and run a TeX engine outside of R.
Problems may also occur if DVI output is produced that ‘xdvir’ cannot read.
For example, if DVI output is produced outside of R using the pdfTeX engine or the upTeX engine, ‘xdvir’ will be unable to correctly read that DVI output.
A more subtle example of this problem can occur with the luaTeX engine when it slips into “base” mode sometimes to typeset mathematical expressions. ‘xdvir’ can only read “node” mode DVI output so the rendered characters may be garbled or it may just produce errors. One option in this case is to explicitly try the XeTeX engine instead (options(xdvir.engine="xetex")).