# [Tex/LaTex] Make matrix inside equation fit the page width in LyX

boxeslyxmatrices

I have a matrix that is a bit too wide to fit inside my page width.

After reading a lot of different answers on the Internet, none really related to LyX, I came up with these three different solutions, all of them involve inserting an ERT (raw LaTeX code, in this case all the lines before and after ). Here is the image:

I don't know if other possibilities also work and which are the advantages or disadvantages, from each method.

The LaTeX source for all this is:

\noindent\makebox[\textwidth]{%
\tiny%
\begin{minipage}[t]{1\columnwidth}%
$$Q=\begin{pmatrix} 0.00301472 & -0.0961879 & -0.00897697 & 0.0389941 & -0.860642 & 0.0131329 & -4.73786 & -0.00552858\\ -0.028584 & 0.615003 & 0.111671 & -0.371008 & 4.94379 & -0.138279 & 20.3258 & 0.0512362\\ 0.0132728 & -0.345125 & -0.0701132 & 0.115389 & -3.11777 & 0.102871 & -16.9949 & -0.0408223\\ 2.91757 & 1.03545 & -5.16595 & 1.69976 & -22.1649 & 4.33453 & 120.513 & -1.35074\\ 0.867566 & 2.92363 & -1.14174 & 3.4356 & -2.96193 & 1.91413 & -113.348 & -0.684269 \end{pmatrix}$$
%
\end{minipage}}

\resizebox{\textwidth}{!}{%
\tiny%
\begin{minipage}[t]{1\columnwidth}%
$$Q_{ij}=\left(\begin{array}{cccccccc} 0.00301472 & -0.0961879 & -0.00897697 & 0.0389941 & -0.860642 & 0.0131329 & -4.73786 & -0.00552858\\ -0.028584 & 0.615003 & 0.111671 & -0.371008 & 4.94379 & -0.138279 & 20.3258 & 0.0512362\\ 0.0132728 & -0.345125 & -0.0701132 & 0.115389 & -3.11777 & 0.102871 & -16.9949 & -0.0408223\\ 2.91757 & 1.03545 & -5.16595 & 1.69976 & -22.1649 & 4.33453 & 120.513 & -1.35074\\ 0.867566 & 2.92363 & -1.14174 & 3.4356 & -2.96193 & 1.91413 & -113.348 & -0.684269 \end{array}\right)$$
%
\end{minipage}}

\noindent%
\begin{minipage}[t]{1\textwidth}%
\tiny
$$Q=\begin{pmatrix} 0.00301472 & -0.0961879 & -0.00897697 & 0.0389941 & -0.860642 & 0.0131329 & -4.73786 & -0.00552858\\ -0.028584 & 0.615003 & 0.111671 & -0.371008 & 4.94379 & -0.138279 & 20.3258 & 0.0512362\\ 0.0132728 & -0.345125 & -0.0701132 & 0.115389 & -3.11777 & 0.102871 & -16.9949 & -0.0408223\\ 2.91757 & 1.03545 & -5.16595 & 1.69976 & -22.1649 & 4.33453 & 120.513 & -1.35074\\ 0.867566 & 2.92363 & -1.14174 & 3.4356 & -2.96193 & 1.91413 & -113.348 & -0.684269 \end{pmatrix}$$
%
\end{minipage}


Is there a simpler way of doing this in LyX, for example without using the \tiny command and inserting boxes inside boxes? Can't LaTeX simply determine when a matrix is too big and rescale it to fit the page?

This is how it looks like in the output: 2

You may want to consider whether it's absolutely necessary to show up to 8 digits after the decimal point in order to convey the message you intend to send. If you can make do with, say, 4 digits after the decimal, you could use the siunitx package and its S column type to show the matrix in the form shown below. Note that it's not necessary to round and truncate the numbers by hand; siunitx will take of this job for you.

Incidentally, if the S column type is used, all numbers are aligned on the decimal points -- presumably a desirable thing, right? Note that with these modifications, it's not necessary at all to reduce the font size.

\documentclass{article}
\usepackage[margin=1in]{geometry} %
\usepackage{siunitx}
\sisetup{round-mode=places,       % enable rounding
round-precision=4,       % amounts of digits for rounding
table-format=-1.4}       % default numeric format
\begin{document}
$$Q_{ij}=\left( \begin{array}{*{4}{S} S[table-format=3.4] S S[table-format=4.4] S} % non-default values for "table-format" for columns 5 and 7 0.00301472 & -0.0961879 & -0.00897697 & 0.0389941 & -0.860642 & 0.0131329 & -4.73786 & -0.00552858\\ -0.028584 & 0.615003 & 0.111671 & -0.371008 & 4.94379 & -0.138279 & 20.3258 & 0.0512362\\ 0.0132728 & -0.345125 & -0.0701132 & 0.115389 & -3.11777 & 0.102871 & -16.9949 & -0.0408223\\ 2.91757 & 1.03545 & -5.16595 & 1.69976 & -22.1649 & 4.33453 & 120.513 & -1.35074\\ 0.867566 & 2.92363 & -1.14174 & 3.4356 & -2.96193 & 1.91413 & -113.348 & -0.684269 \end{array} \right)$$
\end{document}