Plots in TikZ don't work

Question

I want to do some plots using TikZ, however the following code doesn't work:

\documentclass{minimal}
\usepackage{amsmath}

\usepackage{pgf,tikz}%
\begin{document}
\begin{tikzpicture}
      \draw[->] (-3,0) -- (2.2,0) node[right] {$x$}; %
      \draw[->] (0,-0.5) -- (0,3.2) node[above] {$y$};%
      \draw plot (\x,{\x^2});%
\end{tikzpicture}
\end{document}

Any idea what's wrong?

How to plot functions like x \mapsto a^x (a > 0)?

Edit: Thanks for the patch, however ploting 2^x doesn't work, I get the following picture using Jakes answer:

enter image description here

Could you please change the image to not include a large white space on top? Also please describe your issue more precise. "Doesn't work" is not very descriptive. — Martin Scharrer, May 19 '11 at 19:11

score 5 · Answer 1 · edited Apr 13 '17 at 12:35

5

As Martin Scharrer pointed out, this is a bug that Hendrik Vogt has provided a patch for in his answer to the question How can I work around this TikZ bug: (\x)^2 and \x^2 produce different results in TikZ plot?

On a side note: tikz loads pgf automatically, so you don't need to load it explicitly.

\documentclass{article}

\usepackage{tikz}%

\makeatletter
\def\tikz@scan@no@calculator#1(#2){%
    \patch@tikz(#2)%
    \expandafter\tikz@@scan@@no@calculator\expandafter#1\tikz@temp
    }
\def\patch@tikz(#1,#2){%
    {\expandafter\let\expandafter\save@tikz@plot@var\tikz@plot@var
     \expandafter\def\tikz@plot@var{(\save@tikz@plot@var)}%
     \xdef\tikz@temp@i{#1}%
     \xdef\tikz@temp@ii{#2}%
     }%
    \edef\tikz@temp{({\tikz@temp@i},{\tikz@temp@ii})}%
    }
\makeatother

\begin{document}
\begin{tikzpicture}
      \draw[->] (-2.2,0) -- (2.2,0) node[right] {$x$}; %
      \draw[->] (0,-0.5) -- (0,3.2) node[above] {$y$};%
      \draw [domain=-2:2,orange] plot (\x,\x^2);
      \draw [domain=-2:2,blue] plot (\x,2^\x);%
\end{tikzpicture}
\end{document}

tikz plot

edited Apr 13 '17 at 12:35

Community

1

answered May 19 '11 at 19:08

Jake

232,450

1

Is this that PGF bug for v2.1 (or was it v2.x)? – Martin Scharrer May 19 '11 at 19:10
@Martin: Indeed, you're right. Thanks for pointing that out. So this should be closed as a duplicate? – Jake May 19 '11 at 19:18
Thanks, however plotting 2^\x seems not to work – student May 19 '11 at 19:29
@user4011: It does for me, see the edited answer. Maybe you'se using an old version of TikZ? – Jake May 19 '11 at 19:37
@Jake: How to find out the tikz version? See my edit above – student May 19 '11 at 19:46
@user4011: Just add \pgfversion to your document just after \begin{document}, the version will then be shown in the document. – Jake May 19 '11 at 20:31
@Jake: \pgfversion gives 2.10 – student May 20 '11 at 16:47
@user4011: That should work fine. Could you compile the file again after adding \listfiles, and then edit your question to include the list of used files that you can find near the end of the .log file? – Jake May 21 '11 at 14:20
The patch described above did not work for me when dealing with more complicated power functions; instead I used this alternative patch http://tex.stackexchange.com/a/31791/14564 – Sergio Parreiras Dec 18 '12 at 08:19

Plots in TikZ don't work

1 Answers1