Dambo - 3 months ago 23

LaTeX Question

I have this latex code in an RMarkdown file in R studio:

`---`

title: "matrix"

date: "November 2, 2016"

output:

pdf_document: default

---

$$

\mathbf{y} = \left[\begin{array}

{rrr}

y_{1,1} \\

y_{4,3}

\end{array}\right]

\mathbf{X} = \left[\begin{array}

{rrr}

1 & 0 & 0 & 0 \\

1 & 0 & 0 & 0

\end{array}\right]

$$

The preview shows up fine in Rstudio:

But when I knit to pdf I get this error message:

`! LaTeX Error: \mathbf allowed only in math mode.`

See the LaTeX manual or LaTeX Companion for explanation.

Type H <return> for immediate help.

...

l.88 \$\$ \mathbf{y}

pandoc: Error producing PDF

Error: pandoc document conversion failed with error 43

Execution halted

How can I fix it?

Answer

Works okay if you change to an explicit math environment:

```
---
title: "matrix"
date: "November 2, 2016"
output:
pdf_document: default
---
\begin{equation}
\mathbf{y} = \left[\begin{array}
{r}
y_{1,1} \\
y_{4,3}
\end{array}\right]
\mathbf{X} = \left[\begin{array}
{rrrr}
1 & 0 & 0 & 0 \\
1 & 0 & 0 & 0
\end{array}\right]
\end{equation}
```

except you also want to fix your array alignments, otherwise

```
Extra alignment tab has been changed to \cr.
```

(you need just `{r}`

for the first, and `{rrrr}`

for the second)