Write elements above and right outside the matrix

Question

I found writing matrix's code is a boring work. There is one, you can see in pic below.

Can anybody help?

Thanks. I found only the blkarray package may provide help (Was I wrong?) from your links. But there is a large warning in its PDF document's. Can I use it without leading to any incompatibility? — may you, Feb 23 '12 at 03:38

score 10 · Accepted Answer · edited Jun 11 '17 at 09:26

10

This is definitely possible when using the blkarray package. Here's a mock-up with some index styling (in \scriptsize):

enter image description here

\documentclass{article}
\usepackage{blkarray}% http://ctan.org/pkg/blkarray
\newcommand{\matindex}[1]{\mbox{\scriptsize#1}}% Matrix index
\begin{document}
\[
  A=\begin{blockarray}{ccc}
    \matindex{1} & \matindex{2} & \\
    \begin{block}{(cc)c}
      a & b & \matindex{3} \\
      c & d & \matindex{4} \\
      e & f &   \\
    \end{block}
  \end{blockarray}
\]
\end{document}

This would also be doable using a plain array, but would require additional vertical alignment/compensation, perhaps removing some of the code readability that exists via blkarray.

edited Jun 11 '17 at 09:26

Moriambar

11,466

answered Feb 23 '12 at 05:37

Werner

603,163

Hi Werner. I found your answer helpful. How does one selectively adjust the spacing between the block and the elements exterior to the block? – user001 Mar 21 '12 at 01:12
@user001: Just on one side, or both (right and above)? – Werner Mar 25 '12 at 21:29
Preferably I would like to adjust the spacing between the top elements and the matrix and the right elements and the matrix to different extents. – user001 Mar 26 '12 at 01:20

score 3 · Answer 2 · answered Apr 21 '21 at 12:44

The package nicematrix has tools to address that kind of problem.

\documentclass{article}
\usepackage{nicematrix}
\begin{document}
\[
  \NiceMatrixOptions{code-for-first-row=\scriptstyle,code-for-last-row=\scriptstyle}
  A=\begin{pNiceMatrix}[first-row,last-col=3]
      1 & 2 & \\
      a & b & 3 \\
      c & d & 4 \\
      e & f &   \\
  \end{pNiceMatrix}
\]
\end{document}

Write elements above and right outside the matrix

2 Answers2

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