3

Lets say I have a 5x5 matrix. I want to place 2 leftrightarrows (with descriptions "3", "2") underneath the matrix, but really close to it: first pointing from col1 to col3 and second from col4 to col5. Plus updownarrows with similar outcome. How can I achieve that?

draft:

1 1 1 | 1 1

<--> <->

F. Pantigny
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Lucas
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  • Welcome to TeX.SX! Please help us (and also you) and add a minimal working example (MWE), that illustrates your problem. Reproducing the problem and finding out what the issue is will be much easier when we see compilable code, starting with \documentclass and ending with \end{document}. - Related: https://tex.stackexchange.com/a/32981/124842, https://tex.stackexchange.com/q/40535/124842 – Bobyandbob Oct 15 '17 at 11:01

2 Answers2

4

enter image description here

matrix is drawn ... :-)

\documentclass[tikz,border=5mm]{standalone}
\usetikzlibrary{arrows.meta, matrix, quotes, positioning}

\begin{document}
\begin{tikzpicture}[LA/.style = {Straight Barb-Straight Barb,
                                 shorten <=1pt, shorten >=1pt,
                                 draw=red}
                    ]
\matrix (m) [matrix of math nodes,
             left  delimiter={[},
             right delimiter={]}
             ]
{
1 & 1 & 1 & 1 & 1 \
1 & 1 & 1 & 1 & 1 \
1 & 1 & 1 & 1 & 1 \
1 & 1 & 1 & 1 & 1 \
1 & 1 & 1 & 1 & 1 \
};
\draw (m-1-3.north east) -- (m-5-3.south east);
\draw (m-4-1.north west) -- (m-4-5.north east);
%
\draw[LA] (m-5-1.south west |- m.south) to ["3" '] (m-5-3.south east |- m.south);
\draw[LA] (m-5-4.south west |- m.south) to ["2" '] (m-5-5.south east |- m.south);
%
\coordinate[right=5mm of m.east] (e);
\draw[LA] (m-1-5.north east -| e) to ["3"] (m-3-5.south east -| e);
\draw[LA] (m-4-5.north east -| e) to ["2"] (m-5-5.south east -| e);
\end{tikzpicture}
\end{document}
user2740
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  • 2
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Zarko
  • 296,517
  • Thank You, it's exactly what I wanted :) But still I'm struggling with updownarrows on the right of matrix. Could you recomend me a book or script with documentation about matrix and arrows in tikz? – Lucas Oct 19 '17 at 13:49
  • @Lucas, where should be this arrows? your question is not clear about this. i only figured out these in my answer. – Zarko Oct 19 '17 at 13:53
  • Outside of the matrix, on the right. Just like if You flip matrix from your answer 90 degrees counter clockwise. – Lucas Oct 19 '17 at 13:57
  • Something like this, but with straight updownarrow: https://tex.stackexchange.com/questions/340919/row-reduction-arrow-to-indicate-row-switch/340926 And I want to make 2 arrows, just like last time (values "3" and "2"). – Lucas Oct 19 '17 at 14:07
  • I wrote "Lets say I have a 5x5 matrix." at the begining of the question, but true, I should include sketch and I will. – Lucas Oct 19 '17 at 14:32
  • see edited answer – Zarko Oct 19 '17 at 14:54
3

Here is what you can do with the latest version of nicematrix ( ≥ v. 6.22 2023-08-14).

\documentclass{article}
\usepackage{nicematrix,tikz}

\NiceMatrixOptions
  {
    code-for-first-row = \color{red} ,
    code-for-last-col = \color{red} ,
    xdots/horizontal-labels
  }


\begin{document}


$\begin{pNiceArray}{ccc|cc}[first-row,last-col,xdots/line-style=<->,margin=2pt]
\Hdotsfor{3}^{3} & \Hdotsfor{2}^{2} \
1 & 1 & 1 & 1 & 1 & \Vdotsfor{3}^{3}\
1 & 1 & 1 & 1 & 1 \
1 & 1 & 1 & 1 & 1 \
\hline
1 & 1 & 1 & 1 & 1 & \Vdotsfor{2}^{2}\
1 & 1 & 1 & 1 & 1 \
\end{pNiceArray}$


\end{document}

You need several compilations (because nicematrix uses PGF/Tikz nodes).

Output of the above code

F. Pantigny
  • 40,250
  • Happy and prosper new year! I believe that v 5.8 if from this year: 20201? If so, you start to work in the very first day :-) ... (+1) – Zarko Jan 03 '21 at 09:43
  • @Zarko: Yes, you are right. I will modify the date. Happy new year. – F. Pantigny Jan 03 '21 at 09:53