如何使用 TikZ 資料視覺化繪製磁滯迴線？

Question

抱歉我的英語不正確。

我已經修改了程式碼這裡使其適應TikZ datavisualization.這是改編後的代碼：

\documentclass{scrartcl}
\usepackage{tikz}
\usepackage[per-mode = fraction]{siunitx}
\usetikzlibrary{datavisualization.formats.functions}
\begin{document}
  \begin{tikzpicture}
    \datavisualization[
                       scientific axes = {clean, end labels},
                       all axes = {ticks and grid = {major at = 0}},
                       x axis = {label = $\frac{H}{\si{\A\per\m}}$},
                       y axis = {label = $\frac{B(H)}{\si{\tesla}}$},
                       data/format = function,
                       visualize as smooth line/.list = {left, right}
                      ]
    data[set = left] {
      var x : interval [-7 : 7];
      func y = 5 / (1 + exp(-1.7 * \value x - 1.5)) - 2.5;
    }
    data[set = right] {
      var x : interval [-7 : 7];
      func y = 5 / (1 + exp(-1.7 * \value x + 1.5)) - 2.5;
    }
    %accents important points
    info {
      \draw (visualization cs:x = {(-1.5 / 1.7)}, y = 0) circle [radius = 1pt]
        node [left, font = \footnotesize] {$H_C$};
    }
    info {
      \draw (visualization cs:x = 0, y = 1.59) circle [radius = 1pt]
        node [left, font=\footnotesize] {$B_R$};
    }
    info {
      \draw (visualization cs:x = 7, y = 2.5) circle [radius = 1pt]
        node [above, font=\footnotesize] {$B_S$};
    };
  \end{tikzpicture}
\end{document}

但我遇到了很多這樣的錯誤：

！尺寸太大。 \pgfmath@iterate…\pgfmath@xa \ifdim \pgfmath@x

可以TikZ fpu像以前一樣使用這裡,這裡和這裡。這是我的程式碼：

\documentclass{scrartcl}
\usepackage{tikz}
\usepackage[per-mode = fraction]{siunitx}
\usetikzlibrary{datavisualization.formats.functions,fpu}
\begin{document}
  \begin{tikzpicture}
    \datavisualization[
                       scientific axes = {clean, end labels},
                       all axes = {ticks and grid = {major at = 0}},
                       x axis = {label = $\frac{H}{\si{\A\per\m}}$},
                       y axis = {label = $\frac{B(H)}{\si{\tesla}}$},
                       data/format = function,
                       visualize as smooth line/.list = {left, right}
                      ]
    data[set = left] {
      var x : interval [-7 : 7];
      \pgfkey{/pgf/fpu, /pgf/fpu/output format=fixed}
      func y = 5 / (1 + exp(-1.7 * \value x - 1.5)) - 2.5;
      \pgfkeys{/pgf/fpu=false}
    }
    data[set = right] {
      var x : interval [-7 : 7];
      \pgfkey{/pgf/fpu, /pgf/fpu/output format=fixed}
      func y = 5 / (1 + exp(-1.7 * \value x + 1.5)) - 2.5;
      \pgfkeys{/pgf/fpu=false}
    }
    %accents important points
    info {
      \draw (visualization cs:x = {(-1.5 / 1.7)}, y = 0) circle [radius = 1pt]
        node [left, font = \footnotesize] {$H_C$};
    }
    info {
      \draw (visualization cs:x = 0, y = 1.59) circle [radius = 1pt]
        node [left, font=\footnotesize] {$B_R$};
    }
    info {
      \draw (visualization cs:x = 7, y = 2.5) circle [radius = 1pt]
        node [above, font=\footnotesize] {$B_S$};
    };
  \end{tikzpicture}
\end{document}

但我的pdfLaTeX編譯器TeXnicCenter陷入了無限迴圈。我有什麼錯嗎？

順便一提：上面的裝飾線看起來已經一樣了（只是座標、對齊方式和文字發生了變化）。有沒有辦法結合/優化它。

提前謝謝你的幫忙！

Answer 1

似乎當 x 值變成“大”負數時，它就會崩潰。如果將曲線的下限更改left為 -6.5，並將right曲線的下限更改為 -4.5，則此處可以正常編譯。

\documentclass{scrartcl}
\usepackage{tikz}
\usepackage[per-mode = fraction]{siunitx}
\usetikzlibrary{datavisualization.formats.functions}
\begin{document}
  \begin{tikzpicture}
    \datavisualization[
                       scientific axes = {clean, end labels},
                       all axes = {ticks and grid = {major at = 0}},
                       x axis = {label = $\frac{H}{\si{\A\per\m}}$},
                       y axis = {label = $\frac{B(H)}{\si{\tesla}}$},
                       data/format = function,
                       visualize as smooth line/.list = {left, right}
                      ]
    data[set = left] {
      var x : interval [-6.5 : 7];
      func y = 5 / (1 + exp(-1.7 * \value x - 1.5)) - 2.5;
    }
    data[set = right] {
      var x : interval [-4.5 : 7];
      func y = 5 / (1 + exp(-1.7 * \value x + 1.5)) - 2.5;
    }
    %accents important points
    info {
      \draw (visualization cs:x = {(-1.5 / 1.7)}, y = 0) circle [radius = 1pt]
        node [left, font = \footnotesize] {$H_C$};
    }
    info {
      \draw (visualization cs:x = 0, y = 1.59) circle [radius = 1pt]
        node [left, font=\footnotesize] {$B_R$};
    }
    info {
      \draw (visualization cs:x = 7, y = 2.5) circle [radius = 1pt]
        node [above, font=\footnotesize] {$B_S$};
    };
  \end{tikzpicture}
\end{document}