pgfplots: gnuplot fails to plot series

Question

I want to plot a function containing a (converging) series. To plot this function I changed the series to a finite sum.

\documentclass{standalone}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=1.8}
\begin{document}  

\begin{tikzpicture}
  \begin{axis}[
           domain = 0:1,
           samples = 501,
           ]
  \addplot+[mark = none] gnuplot[raw gnuplot] {%
    set samples 501;
    dist(x) =  x - floor(x) < 0.5 ? x - floor(x) : 1 - (x - floor(x));
    plot[0:1] sum [k=0:5] (2^(-k) * dist(2^(2^k) * x))
  };
  \end{axis}
\end{tikzpicture}
\end{document}

If I do k=0:4, it works fine. But the example above I tried k=0:5 and although a plot is created this plot has nothing do to with my function.

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I guess is overflow in gnuplot; 2^(2^5) is 2^32 which could easily be out of its range of floating point arithmetic — Andrew Swann, Jan 21 '14 at 14:40
Ah, sounds plausible. Is there a way to use larger floating point numbers in gnuplot? — Keba, Jan 21 '14 at 15:10
I checked, that floor(2 ** 32) is negative (in gnuplot!) the error may be there. — Keba, Jan 21 '14 at 17:43
On my system, I get line 0: undefined variable: sum. Did I miss something? Is my gnuplot outdated? gnuplot 4.4 patchlevel 2 — Christian Feuersänger, Jan 21 '14 at 18:54
That is a typical sign of overflow. This discussion http://stackoverflow.com/q/14052115 seems relevant. It also reminds us that we are off topic for TeX.SX — Andrew Swann, Jan 22 '14 at 19:35

pgfplots: gnuplot fails to plot series

0 Answers0