How to draw a separator between the columns of a matrix.
You can use "matrix of nodes" and anchors:
\begin{tikzpicture}
\matrix (mat) [matrix of nodes]
{
1 & 2 & 3 \\
1 & 2 & 3 \\
1 & 2 & 3 \\
1 & 2 & 3 \\
};
% Matrix is called 'mat' first number is row, second numer is column
\draw[thick,red] (mat-1-1.north east) -- (mat-4-1.south east);
\end{tikzpicture}
Here's an answer based on answers given at Obstacles to simulating an amsmath matrix by a TiKZ matrix of math nodes and How can I set the background color of the rows and columns of a matrix node in Tikz? You don't specify in the question what type of matrix you are wanting to typeset, so I've simply gone for a similar matrix to that which Stefan and xeroc have used. Exactly what code you need depends a lot on what your matrix code looks like. The only one that you really need is the code from How can I set the background color of the rows and columns of a matrix node in Tikz? The others are there to make it look more impressive.
If the code from How can I set the background color of the rows and columns of a matrix node in Tikz? were in a package (below called tikzamsmatrix), the document would look like this:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{matrix,decorations}
\usepackage{calligraphy}
\usepackage{matrixcells}
\usepackage{tikzamsmatrix}
\begin{document}
\[
\begin{tikzamatrix}
a & b & 0 \\
c & a + c & {\displaystyle \int_0^1 \sin(x) d x}
\end{tikzamatrix}
\]
\end{document}
and would produce:
Since that question isn't yet in a package, the code actually looks like this:
\documentclass{article}
%\url{https://tex.stackexchange.com/q/9492/86}
\usepackage{amsmath,tikz}
\usetikzlibrary{matrix,decorations}
\usepackage{calligraphy}
\usepackage{matrixcells}
\newlength\mtxrowsep
\setlength\mtxrowsep{1.5ex}
\newlength\mtxcolsep
\setlength\mtxcolsep{2\arraycolsep}
\makeatletter
\pgfdeclaredecoration{doubled lineto}{brace}
{
\state{brace}[width=+\pgfdecoratedremainingdistance,next state=final]
{
\pgfsyssoftpath@setcurrentpath{\pgfutil@empty}
\pgfpathmoveto{\pgfpointorigin}
\pgfpathlineto{\pgfqpoint{\pgfdecoratedremainingdistance}{0pt}}
\pgfpathmoveto{\pgfqpoint{0pt}{\pgfdecorationsegmentamplitude}}
\pgfpathlineto{\pgfqpoint{\pgfdecoratedremainingdistance}{\pgfdecorationsegmentamplitude}}
}
\state{final}{}%
}
\pgfdeclaredecoration{bracket}{brace}
{
\state{brace}[width=+\pgfdecoratedremainingdistance,next state=final]
{
\pgfsyssoftpath@setcurrentpath{\pgfutil@empty}
\pgfpathmoveto{\pgfpointorigin}
\pgfpathlineto{\pgfqpoint{0pt}{\pgfdecorationsegmentamplitude}}
\pgfpathlineto{\pgfqpoint{\pgfdecoratedremainingdistance}{\pgfdecorationsegmentamplitude}}
\pgfpathlineto{\pgfqpoint{\pgfdecoratedremainingdistance}{0pt}}
}
\state{final}{}%
}
\makeatother
\expandafter\def\csname delimiter \string\lbrace\endcsname{calligraphic brace}
\expandafter\def\csname delimiter \string(\endcsname{calligraphic curved parenthesis}
\expandafter\def\csname delimiter \string|\endcsname{lineto}
\expandafter\def\csname delimiter \string\|\endcsname{doubled lineto}
\expandafter\def\csname delimiter \string[\endcsname{bracket}
\expandafter\def\csname delimiter \string\rbrace\endcsname{calligraphic brace}
\expandafter\def\csname delimiter \string)\endcsname{calligraphic curved parenthesis}
\expandafter\def\csname delimiter \string]\endcsname{bracket}
\tikzset{
ams/.style={
baseline=-.7ex,
every delimiter/.style={yshift=-1pt},
every left delimiter/.style={xshift=2pt},
every right delimiter/.style={xshift=-2pt},
every node/.style={inner sep=0pt},
execute at end picture={
\path (current bounding box.east) ++(\pgfkeysvalueof{/tikz/ams matrix xsep},0) (current bounding box.west) ++(-\pgfkeysvalueof{/tikz/ams matrix xsep},0);
},
},
ams matrix xsep/.initial={.5ex},
ams matrix/.style={
inner sep=1pt,
column sep=\mtxcolsep,
row sep=\mtxrowsep,
% ampersand replacement=\&,
matrix of math nodes,
},
ams delimiters/.style args={#1,#2}{
left delimiter={#1},
right delimiter={#2},
},
delimiters/.style args={#1,#2}{
\pgfkeysvalueof{/tikz/matrix delimiter type} delimiters={{#1},{#2}},
},
matrix delimiter type/.initial={tikz},
tikz delimiter style/.style={
thick,
},
tikz delimiters/.style args={#1,#2}{
left tikz delimiter={#1},
right tikz delimiter={#2},
},
left tikz delimiter/.style={
render left tikz delimiter/.expand once={\csname delimiter \string#1\endcsname}
},
render left tikz delimiter/.style={
append after command={(\tikzlastnode.north west) edge[tikz delimiter style,decorate,decoration={mirror,#1}] (\tikzlastnode.south west)}
},
right tikz delimiter/.style={
render right tikz delimiter/.expand once={\csname delimiter \string#1\endcsname}
},
render right tikz delimiter/.style={
append after command={(\tikzlastnode.north east) edge[tikz delimiter style,decorate,decoration={#1}] (\tikzlastnode.south east)}
},
bmatrix/.style={
ams,
every matrix/.style={
ams matrix,
delimiters={[,]},
}
},
Bmatrix/.style={
ams,
every matrix/.style={
ams matrix,
delimiters={\lbrace,\rbrace},
}
},
pmatrix/.style={
ams,
every matrix/.style={
ams matrix,
delimiters={(,)},
}
},
vmatrix/.style={
ams,
every matrix/.style={
ams matrix,
delimiters={|,|},
}
},
Vmatrix/.style={
ams,
every matrix/.style={
ams matrix,
delimiters={\|,\|},
}
},
}
\let\matamp=&
\catcode`\&=13
\makeatletter
\def&{\iftikz@is@matrix
\pgfmatrixnextcell
\else
\matamp
\fi}
\makeatother
%\usepackage{environ}
\def\endtikzmatrix{\\\egroup;\end{tikzpicture}}
\foreach \mtype in {b,B,p,v,V} {
\expandafter\xdef\csname tikz\mtype matrix\endcsname{%
\noexpand\begin{tikzpicture}[\mtype matrix,matrix delimiter type={tikz}]
\noexpand\matrix \noexpand\bgroup}
\expandafter\xdef\csname ams\mtype matrix\endcsname{%
\noexpand\begin{tikzpicture}[\mtype matrix,matrix delimiter type={ams}]
\noexpand\matrix \noexpand\bgroup}
\expandafter\global\expandafter\let\csname endtikz\mtype matrix\endcsname=\endtikzmatrix
\expandafter\global\expandafter\let\csname endams\mtype matrix\endcsname=\endtikzmatrix
}
\def\tikzamatrix{\begin{tikzpicture}[pmatrix,matrix delimiter type={tikz}]\matrix[label cells,name=am]\bgroup}
\def\endtikzamatrix{\\\egroup;\draw (am-cell-1-\the\pgfmatrixcurrentcolumn.north west) -- (am-cell-\the\pgfmatrixcurrentrow-\the\pgfmatrixcurrentcolumn.south west);\end{tikzpicture}}
\begin{document}
\begin{tikzamatrix}
a & b & 0 \\
c & a + c & {\displaystyle \int_0^1 \sin(x) d x}
\end{tikzamatrix}
\end{document}
(The calligraphy and matrixcells package are available from TeX-SX launchpad page.)
Here's an example with a matrix of math nodes, with delimiters and a separation line with some shifting for that.
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{matrix}
\begin{document}
\begin{tikzpicture}
\matrix (m) [matrix of math nodes,left delimiter=(,right delimiter=),
inner sep=2pt,outer sep=0pt]{
a & b & [1em] 0 \\
c & d & 1 \\ };
\draw ([xshift=0.5em]m-1-2.north east) -- ([xshift=0.5em]m-2-2.south east);
\end{tikzpicture}
\end{document}
If the entries would have different width, you could use |- instead of -- to get straight lines, such as
\draw ([xshift=0.5em]m-1-2.north east-|m-2-2.south east) -|
([xshift=0.5em]m-2-2.south east);
Even better: set the minimum width property for the nodes in the matrix.