Cannot get LyX to produce two plots are not on same line when using knitr

Question

Knitr newbie here. Love the package, and everything is going well except that two plots don't appear side-by-side once compiled in LyX. Not sure what is going on, as I'm copying the example from the knitr graphics manual (knitr-graphics.lyx) verbatim.

My LyX code (within a Figure Float):

<<two-high, fig.width=3, fig.height=2.5, out.width='0.49\\linewidth'>>=
plot(cars)
boxplot(cars$dist,xlab='dist')
@

I can't post an image, but in the compiled pdf the plots appear under each other, not side-by-side.

My code was copied directly from the knitr graphics manual so I don't understand why the plots are not side-by-side.

Changing the out.width multiplier does change the width of the plots, but at no time do they appear on the same line.

Any suggestions?

LyX Version 2.0.5.1 R version 3.0.1 knitr 1.5

Answer 1

There was a global option fig.show set in the first chunk:

opts_chunk$set(fig.show='hold')

And that option is critical here. You may see a simpler example here. Alternatively, you can use it as a local option:

<<two-high, fig.width=3, fig.height=2.5, fig.show='hold', out.width='0.49\\linewidth'>>=
plot(cars)
boxplot(cars$dist,xlab='dist')
@