Take the 2-minute tour ×
TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It's 100% free, no registration required.

I am trying to use the Gauss TeX package to display matrices. I have two problems with the following code (not so important):

    \usepackage{amsmath}
\usepackage{gauss}     
\begin{document}
\begin{equation}\begin{gmatrix}[b]
 1 & 0 & 0 & 0 & \frac{4}{5} & \text{\small{-}}\frac{3}{5} & \frac{2}{5} & \text{\small{-}}\frac{1}{5} \\
 0 & 1 & 0 & 0 & \text{\small{-}}\frac{3}{5} & \frac{6}{5} & \text{\small{-}}\frac{4}{5} & \frac{2}{5} \\
 0 & 0 & 1 & \frac{3}{4} & \frac{1}{4} & \text{\small{-}}\frac{1}{2} & \frac{3}{4} & 0 \\
 0 & 0 & 0 & 1 & \text{\small{-}}\frac{1}{5} & \frac{2}{5} & \text{\small{-}}\frac{3}{5} & \frac{4}{5}
\rowops
\add[\cdot ({-}\frac{3}{4})]{3}{2}
\end{gmatrix} \cong
\begin{gmatrix}[b]
 1 & 0 & 0 & 0 & \frac{4}{5} & \text{\small{-}}\frac{3}{5} & \frac{2}{5} & \text{\small{-}}\frac{1}{5} \\
 0 & 1 & 0 & 0 & \text{\small{-}}\frac{3}{5} & \frac{6}{5} & \text{\small{-}}\frac{4}{5} & \frac{2}{5} \\
 0 & 0 & 1 & 0 & \frac{2}{5} & \text{\small{-}}\frac{4}{5} & \frac{6}{5} & \text{\small{-}}\frac{3}{5} \\
 0 & 0 & 0 & 1 & \text{\small{-}}\frac{1}{5} & \frac{2}{5} & \text{\small{-}}\frac{3}{5} & \frac{4}{5}
\end{gmatrix}\end{equation}
\end{document}

It looks like this:

alt text

I bypassed the alignment a bit by using "\text{\small{-}}" in stead of "-", to make the fractions appear under each other, but they still don't line up quite nicely and the matrix need more vertical space but I cannot seem to figure out how to do this. Any help would be appreciated :-)

share|improve this question
add comment

2 Answers

up vote 1 down vote accepted

The gauss package seems to impede easy answers. Here's a solutions that isn't great but works: Replace all your \text{\small{-}} with \llap{-} (this will yield the alignment you desire), and add a strut to each row:

\documentclass{article}
\usepackage{amsmath}
\usepackage{gauss}
\newcommand\mystrut{\rule{0pt}{2.5ex}}
\begin{document}
\begin{equation}\begin{gmatrix}[b]
 1 & 0 & 0 & 0 & \frac{4}{5} & \llap{-}\frac{3}{5} & \frac{2}{5} & \llap{-}\frac{1}{5} \mystrut \\
 0 & 1 & 0 & 0 & \llap{-}\frac{3}{5} & \frac{6}{5} & \llap{-}\frac{4}{5} & \frac{2}{5} \mystrut \\
 0 & 0 & 1 & \frac{3}{4} & \frac{1}{4} & \llap{-}\frac{1}{2} & \frac{3}{4} & 0 \mystrut \\
 0 & 0 & 0 & 1 & \llap{-}\frac{1}{5} & \frac{2}{5} & \llap{-}\frac{3}{5} & \frac{4}{5} \mystrut
\rowops
\add[\cdot ({-}\frac{3}{4})]{3}{2}
\end{gmatrix} \cong
\begin{gmatrix}[b]
 1 & 0 & 0 & 0 & \frac{4}{5} & \llap{-}\frac{3}{5} & \frac{2}{5} & \llap{-}\frac{1}{5} \mystrut \\
 0 & 1 & 0 & 0 & \llap{-}\frac{3}{5} & \frac{6}{5} & \llap{-}\frac{4}{5} & \frac{2}{5} \mystrut \\
 0 & 0 & 1 & 0 & \frac{2}{5} & \llap{-}\frac{4}{5} & \frac{6}{5} & \llap{-}\frac{3}{5} \mystrut \\
 0 & 0 & 0 & 1 & \llap{-}\frac{1}{5} & \frac{2}{5} & \llap{-}\frac{3}{5} & \frac{4}{5} \mystrut 
\end{gmatrix}\end{equation}
\end{document}

(The builtin \strut is a bit too small, so I defined a larger \mystrut.)

share|improve this answer
    
Thank you so much! :-) –  user1912 Nov 15 '10 at 18:23
    
@user1912: You might want to check back; it could happen that tomorrow someone has a better answer. –  Hendrik Vogt Nov 15 '10 at 18:25
    
Yea I will surely do that, however, your answer perfectly does the job and all looks fine. I don't care if the underlying code is a bit "hacky" as noone but me sees it –  user1912 Nov 15 '10 at 18:30
add comment

One way to get more vertical space is to use \extrarowheight, in the array package. The syntax is \setlength{\extrarowheight}{x}, where x is a measure (e.g., 2pt, 3pt, etc). The effect only occurs if its value plus \baselineskipx\arraystretch is larger than the actual height of the cell. I usually add two or three points, and that makes the fractions come out suitably separated.

share|improve this answer
    
unfortunately this doesn't work with the gauss package which I need to display the steps I am doing. –  user1912 Nov 15 '10 at 17:10
    
@user1912: fair enough. –  Arturo Magidin Nov 15 '10 at 21:34
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.