LaTeX Forum

\documentclass{scrbook} 

\usepackage{tikz} 
\usetikzlibrary{matrix} 
\begin{document} 
\begin{tikzpicture}

	\matrix (m)[matrix of math nodes,left delimiter=[,right delimiter={]},xshift=0cm, yshift=0] {
	    w_{11} & w_{12} & w_{13} \\
	    w_{21} & w_{22} & w_{23} \\
	    w_{31} & w_{32} & w_{33} \\
	    w_{41} & w_{42} & w_{43} \\
	};
	\node[left of=m, xshift=-0.9cm] (a) {=};
	\node[left of=a,yshift=2cm] (b) {};
	\node[left of=a,yshift=-2cm] (c) {};
	\draw[thick,red,decorate,decoration={brace,amplitude=12pt}] (b) -- (c);
	
	\foreach \name/\y/\text in {d/1.2cm/1,e/0/2,f/-1.2cm/3}
			\node[thick,draw,circle, left of=a,xshift=-1cm,yshift=\y,scale=0.8] (\name) {$O_\text$};
	
	\foreach \name/\y/\text in {g/1.7cm/1,h/0/2,i/-1.7cm/3}
			\node[thick,draw,circle, left of=a,xshift=-2.5cm,yshift=\y,scale=0.9] (\name) {$I_\text$};
	
	\foreach \namea in {d,e,f}
		\foreach \nameb in {g,h,i}
			\draw[->] (\nameb) -- (\namea);
\end{tikzpicture}    
\end{document}

\documentclass{scrbook}

\usepackage{tikz}
\usetikzlibrary{matrix}
\begin{document}
\begin{tikzpicture}
  \draw[help lines] (0,0) grid (5,5) ;
  \matrix (m) at (2,3) % <<< Platzierung
    [
      matrix of math nodes,
      left delimiter=[,
      right delimiter={]},
      ampersand replacement=\&
    ]
    {
       1 \& 2 \\
       3 \& 4 \\
    } ;
\end{tikzpicture}
\end{document}

   \matrix (m)[matrix of math nodes,left delimiter=[,right delimiter={]},ampersand replacement=\&,
      xshift=1cm, yshift=1cm] {
       1 \& 2 \\
       3 \& 4 \\
   };

\documentclass{scrbook}

\usepackage{tikz}
\usetikzlibrary{matrix}
\begin{document}
\begin{tikzpicture}
	\matrix (m)[matrix of math nodes,left delimiter=[,right delimiter={]},ampersand replacement=\&] {
	    1 \& 2 \\
	    3 \& 4 \\
	};
\end{tikzpicture}
\end{document}