Math & Science ⇒ how to mark column number on a matrix

[patiobarbecue]

I would like to indicate the column numbers on top of a matrix, how can I do it?

Currently, I use the top row to place column numbers, and it is not beautiful since the bracket[] enclose the top row. Ideally the column number should be outside the bracket.

Also the column number itself should be circled so as to standout from the numbers of the matrix itself. I used \ding{172} and \ding{173} from pifont package, however nothing shows up, though compilation was a success. any idea?

[php1ic]

You could two smaller matrices inside a larger one like this:

Code: Select all

\[
\begin{matrix}

  \begin{matrix}
    a&b&c
  \end{matrix}\\

  \begin{bmatrix}
    1&2&3\\
    4&5&6
  \end{bmatrix}

\end{matrix}
\]

I don't know about the circle around the number, but I have seem a few post about similar things that were solved by using the pgf/TikZ packages.

EDIT: found the post I was thinking of
http://www.latex-community.org/forum/vi ... =44&t=6301

[localghost]

I would like to indicate the column numbers on top of a matrix, how can I do it?

Currently, I use the top row to place column numbers, and it is not beautiful since the bracket[] enclose the top row. Ideally the column number should be outside the bracket.

Also the column number itself should be circled so as to standout from the numbers of the matrix itself. I used \ding{172} and \ding{173} from pifont package, however nothing shows up, though compilation was a success. any idea?

You should build a minimal working example (MWE) that shows the problem. You can also search the forum as well as the "Math mode" document for \bordermatrix.


Best regards and welcome to the board
Thorsten

[patiobarbecue]

Unfortunately, using nested matrix doesn't lead to beautiful alignment. See the example below.

Code: Select all

\begin{matrix}
\begin{matrix}
1 & 2
\end{matrix}
\\
\begin{bmatrix}
-1 & 1\\
0 & 1
\end{bmatrix}
\end{matrix}

The manual for the \bordermatrix says it cannot be used together with AMS math, which disqualify it immediately since I mainly use AMS math. See page 21 of ftp://tug.ctan.org/pub/tex-archive/info ... thmode.pdf

Any other ideas?

[torbjorn t.]

While not its intended use, perhaps you could use the Gauss-package. An example:

Code: Select all

\documentclass[a4paper,12pt]{article}
\usepackage{gauss}
\renewcommand{\colmultlabel}{}


\begin{document}
\[
\begin{gmatrix}[b]
a&b&c \\
d&e&f \\
g&h&i
\colops
\mult{0}{1}
\mult{1}{2}
\mult{2}{3}
\end{gmatrix}
\]
\end{document}

This does leave the problem of making the ring around the column number, for which I have no solution. Have you looked at the post mentioned above, where something like this was done with pgf/Tikz?

[localghost]

[...] The manual for the \bordermatrix says it cannot be used together with AMS math, which disqualify it immediately since I mainly use AMS math. [...]

The exact statement of the »Math mode« document at the referred place is slightly different.

The matrix environment macro cannot be used together with the AMS math package, it redefines this environment (see section 26.6 on page 56).

Hence there is no problem in using the \bordermatrix command even with the suggested enhancement to get the desired result.

Code: Select all

\documentclass[11pt,a4paper,english]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage{amsmath}
\usepackage{pifont}

\makeatletter
\newif\if@borderstar
\def\bordermatrix{\@ifnextchar*{%
\@borderstartrue\@bordermatrix@i}{\@borderstarfalse\@bordermatrix@i*}%
}
\def\@bordermatrix@i*{\@ifnextchar[{\@bordermatrix@ii}{\@bordermatrix@ii[()]}}
\def\@bordermatrix@ii[#1]#2{%
\begingroup
\m@th\@tempdima8.75\p@\setbox\z@\vbox{%
\def\cr{\crcr\noalign{\kern 2\p@\global\let\cr\endline }}%
\ialign {$##$\hfil\kern 2\p@\kern\@tempdima & \thinspace %
\hfil $##$\hfil && \quad\hfil $##$\hfil\crcr\omit\strut %
\hfil\crcr\noalign{\kern -\baselineskip}#2\crcr\omit %
\strut\cr}}%
\setbox\tw@\vbox{\unvcopy\z@\global\setbox\@ne\lastbox}%
\setbox\tw@\hbox{\unhbox\@ne\unskip\global\setbox\@ne\lastbox}%
\setbox\tw@\hbox{%
$\kern\wd\@ne\kern -\@tempdima\left\@firstoftwo#1%
\if@borderstar\kern2pt\else\kern -\wd\@ne\fi%
\global\setbox\@ne\vbox{\box\@ne\if@borderstar\else\kern 2\p@\fi}%
\vcenter{\if@borderstar\else\kern -\ht\@ne\fi%
\unvbox\z@\kern-\if@borderstar2\fi\baselineskip}%
\if@borderstar\kern-2\@tempdima\kern2\p@\else\,\fi\right\@secondoftwo#1 $%
}\null \;\vbox{\kern\ht\@ne\box\tw@}%
\endgroup
}
\makeatother

\begin{document}
  \[
    \bordermatrix[{[]}]{%
      & \text{\ding{192}} & \text{\ding{193}} & \text{\ding{194}} \cr
      & 1 & 1 & 0 \cr
      & 1 & 1 & 0 \cr
      & 1 & 1 & 0 \cr
      & 1 & 0 & 1 \cr
      & 1 & 0 & 1 \cr
      & 1 & 0 & 1
    }
  \]
\end{document}

The code is taken from another thread [1]. I supplemented it with the amsmath package and the pifont font package from PSNFSS.

[1] View topic: Bmatrix Column Headings