You're reading: Travels in a Mathematical World

LaTeX/TikZ to draw a star graph $K_{1,n}$

For a diagram for a class this week, I’ve written a LaTeX command to draw star graphs using TikZ. A star graph $K_{1,n}$ is a graph with a single central node, $n$ radial nodes, and $n$ edges connecting the central node to each radial node. I am sharing this here in case it is useful to anyone else.

The result is a command \stargraph, which takes two parameters, the number of radial nodes and the radius in cm of the graph. Here is the definition of \stargraph and its use in a document.

    \node[circle,fill=black] at (360:0mm) (center) {};
    \foreach \n in {1,...,#1}{
        \node[circle,fill=black] at ({\n*360/#1}:#2cm) (n\n) {};
        \draw (center)--(n\n);
        \node at (0,-#2*1.5) {$K_{1,#1}$}; % delete line to remove label

        % usage: \stargraph{number of radial nodes>0}{radius in cm}

Here is the result of making this document:

Star graph with seven radial nodes

(will not be published)

$\LaTeX$: You can use LaTeX in your comments. e.g. $ e^{\pi i} $ for inline maths; \[ e^{\pi i} \] for display-mode (on its own line) maths.

XHTML: You can use these tags: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>