Gaussian eliminations (gauss package)

Question

I am trying to typeset some examples of Gaussian eliminations in LaTeX. I found the gauss package really simple to use, but couldn't figure out how to put a vertical line in between columns. Here is what I have so far (just a regular matrix)

\documentclass[a4paper,12pt]{article}
\usepackage{gauss}
\usepackage{amsmath,amssymb}
\begin{document}
$\begin{gmatrix}[p]
   2 & 0 & 1 & 1 & 0 & 0 \
   0 & 1 & 0 & 0 & 1 & 0 \
   0 & 0 & 3 & 0 & 0 & 1
   \rowops
   \mult{0}{\cdot \frac{1}{2}}
\end{gmatrix}$
\end{document}

Your code doesn't compile: Missing $ inserted.. Could you extend your code fragment into a working document we can copy and paste please? It helps people help you and is a polite thing to do, I understand you are new so do not worry about not knowing — JamesT, Apr 04 '23 at 07:18
Maybe you will be interested in the following LaTeX package : gaussenv — F. Pantigny, Apr 04 '23 at 08:31

score 4 · Answer 1 · answered Apr 04 '23 at 10:07

You can use https://tex.stackexchange.com/a/146730/4427

\documentclass{article}
\usepackage{amsmath}
\usepackage{gauss}
% patch gauss macros for doing their work in `align'
% and other amsmath environments; see
% http://tex.stackexchange.com/questions/146532/
\usepackage{etoolbox}
\makeatletter
\patchcmd\g@matrix
 {\vbox\bgroup}
 {\vbox\bgroup\normalbaselines}% restore the standard baselineskip
 {}{}
\makeatother
\newcommand{\BAR}{%
  \hspace{-\arraycolsep}%
  \strut\vrule % the \vrule is as high and deep as a strut
  \hspace{-\arraycolsep}%
}
\begin{document}
[
\begin{gmatrix}[p]
2 & 9 & 1 & \BAR & 1 & 0 & 0 \
0 & 1 & 0 & \BAR & 0 & 1 & 0 \
0 & 0 & 3 & \BAR & 0 & 0 & 1
\rowops
 \mult{0}{\cdot \frac{1}{2}}
\end{gmatrix}
]
\end{document}

score 3 · Answer 2 · answered Apr 04 '23 at 07:41

Unfortunately, gauss package does not provide for the use of vertical lines separating columns. I simply used a trick using \bigl| for 3 times.

\documentclass[a4paper,12pt]{article}
\usepackage{gauss}
\usepackage{amsmath,amssymb}
\begin{document}
$\begin{gmatrix}[p]
   2 & 0 & 1  &\bigl| & 1 & 0 & 0 \
   0 & 1 & 0  &\bigl| & 0 & 1 & 0 \
   0 & 0 & 3  &\bigl| & 0 & 0 & 1
   \rowops
   \mult{0}{\cdot \frac{1}{2}}
\end{gmatrix}$
\end{document}

TukieMonster · Answer 3 · 2023-04-04T19:56:23.087

2

As an alternative, may I suggest taking a look at the nicematrix package? I used to work with gauss in the way egreg has suggested above until I discovered nicematrix, and I have never looked back :-). It can do what you want and also offers a host of other options. Here is a suggested solution for your question:

\documentclass[a4paper,12pt]{article}
\usepackage{nicematrix}
\usepackage{amsmath,amssymb}
\begin{document}
  $\begin{pNiceArray}{ccc|ccc}[last-col]
    2 & 0 & 1 & 1 & 0 & 0 & \cdot \frac{1}{2}\
    0 & 1 & 0 & 0 & 1 & 0 \
    0 & 0 & 3 & 0 & 0 & 1
   \end{pNiceArray}$
\end{document}

edited Apr 04 '23 at 19:56

answered Apr 04 '23 at 19:51

TukieMonster

191

1

Where you use gauss package? – Sebastiano Apr 04 '23 at 19:52
1

I don't, I'm using nicematrix instead to achieve the same goal. – TukieMonster Apr 04 '23 at 19:53
1

The user want to use gauss package. – Sebastiano Apr 04 '23 at 19:55

score 0 · Answer 4 · answered Apr 04 '23 at 20:15

An alternative without to use gauss package but the simple functions of amsmath.

\documentclass[a4paper,12pt]{article}
\usepackage{amsmath,amssymb}
\begin{document}
[\left(\begin{array}{ccc|ccc} 
   2 & 0 & 1 & 1 & 0 & 0 \
   0 & 1 & 0 & 0 & 1 & 0 \
   0 & 0 & 3 & 0 & 0 & 1
\end{array}\right)\begin{matrix} | \cdot \frac 12 \ \ \ \end{matrix}]
\end{document}

Gaussian eliminations (gauss package)

4 Answers4