2

I've managed to draw three circles:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric}
\begin{document}
    \begin{tikzpicture}

        \draw (0.0, 0.3) circle [radius=0.45] node (a) {$\alpha$};
        \draw (1.6, 0.3) circle [radius=0.45] node (b) {$\beta$};
        \draw (3.2, 0.3) circle [radius=0.45] node (c) {$\gamma$};

    \end{tikzpicture}
\end{document}

I now wish to draw arrows between the edges of the circles as shown here:

enter image description here

I tried using \draw [->] (a) -- (b); but the arrow-ends both go inside the circles? What am I missing here?

2 Answers 2

6

Much much easier to do this as nodes for the circles not nodes just for the greek letters

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
    \begin{tikzpicture}

      \node[minimum width=1cm,draw,circle] (a) at (0,0) {$\alpha$};
      \node[minimum width=1cm,draw,circle] (b) at ($(a)+(2,0)$) {$\beta$};
      \node[minimum width=1cm,draw,circle] (c) at ($(b)+(2,0)$) {$\gamma$};

      \draw[->] (a) -- (b);
      \draw[->] (c) -- (b);
      
    \end{tikzpicture}
\end{document}
1
  • Thanks! Is it possible to fix the radius for each circle? At the moment it seems you only fix the minimum radius, not the maximum radius
    – Tyler D
    Commented Jun 23, 2020 at 9:23
3

Similarly to @daleif answer (+1), but with relative positioning of nodes and defined common style for circles:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,
                positioning}

\begin{document}
    \begin{tikzpicture}[
node distance = 0mm and 9mm,
     C/.style = {circle, draw, minimum size =9mm, inner sep=0pt},
   arr/.style = {-Straight Barb, semithick} 
                        ]
\node (a) [C]               {$\alpha$};
\node (b) [C, right=of a]   {$\beta$};
\node (c) [C, right=of b]   {$\gamma$};
%
\draw[arr]  (a) -- (b);
\draw[arr]  (c) -- (b);
    \end{tikzpicture}
\end{document}

enter image description here

Addendum: In the case, that radius of nodes is fixed, you need to define text width of circle:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,
                positioning}

\begin{document}
    \begin{tikzpicture}[
node distance = 0mm and 9mm,
     C/.style = {circle, draw, text width=9mm, align=center, inner sep=0pt},
   arr/.style = {-Straight Barb, semithick} 
                        ]
\node (a) [C]               {$\alpha$};
\node (b) [C, right=of a]   {$\beta$};
\node (c) [C, right=of b]   {$\gamma$};
%
\draw[arr]  (a) -- (b);
\draw[arr]  (c) -- (b);
    \end{tikzpicture}
\end{document}

In your particular case the result is the same:

enter image description here

2
  • Thanks! Is it possible to fix the max-radii for the circles?
    – Tyler D
    Commented Jun 23, 2020 at 9:29
  • 1
    @TylerD, to make circle radius independent from its contents, than you need to define =9mmtext width. See addendum in answer.
    – Zarko
    Commented Jun 23, 2020 at 9:35

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