This is because your matrix2latex
function uses cat
and sends its output to the standard output stream, which isn't where knitr
is trying to put the output.
Two solutions: one is to rewrite your function to construct the output as a string using paste
and sprintf
or other string formatting functions, or as a quick hack just wrap it in capture.output
thus:
m2l = function(matr){capture.output(matrix2latex(matr))}
Then in your .Rmd
file:
\begin{displaymath}
\mathbf{X} = `r m2l(x)`
\end{displaymath}
becomes
\mathbf{X} = \begin{bmatrix} , 0.06099 & 0.768 \\ , 0.6112 & 0.004696 \\ , 0.02729 & 0.6198 \\ , 0.8498 & 0.3308 \\ , 0.6869 & 0.103 \\ , \end{bmatrix}
which although isn't quite perfect does illustrate the principle. The code inserted by the inline expression is the value of it, not what it prints or cats.