使用 pgfplots 和自定义代码加载 siunitx 包时出错 我包含了一些似乎与 `\siunitx` 不兼容的代码。我该如何修复它？

Question

我发现了一些代码PGFPlots 中带有三角标签的轴

在三角图中使用倍数，但如果我还加载我想要的，\pi就会导致错误。\siunitx

列出的错误包括：

xparse 函数无法扩展

包 \siunitx 错误无效的数字输入

软件包 tikz 数学库错误：未知函数或关键字\num 错误

有人能帮我协调两者吗？我想要代码提供的功能，但也要保留 的功能\siunitx。我希望有人能帮我修复错误并简单解释一下我的错误。

\documentclass[11pt]{exam}
\usepackage{mathtools}
\usepackage{xcolor}
\usepackage{amssymb}
\usepackage{pifont}
\usepackage{array}
\usepackage{tikz}
\usepackage{xintexpr}
\usetikzlibrary{math}
\usepackage{xfp}
\usepackage[font=scriptsize,hypcap=false]{caption}
\usepackage{pgfplots}
\pgfplotsset{width=10cm,compat=1.16}
%\usepackage{siunitx}   %%%%if this is loaded, it causes an error. 

\pgfplotsset{
    % Typeset fractions of pi at regular intervals on x axis
    x axis in pi/.style={
        % Make sure the x axis is in radians
        trig format plots=rad,
        % Set tick distance from style argument
        xtick distance={pi/#1},
        % Set label style: calculate reduced fraction of pi
        xticklabel={
            \tikzmath{
                % Calculate this tick's multiple of pi/#1
                int \numorig, \gcd, \number, \denom, \absnum;
                \numorig = round(\tick*#1/pi);
                % Calculate reduced fraction for \numorig/#1
                \gcd = gcd(\numorig,#1);
                \number = \numorig / \gcd;
                \absnum = abs(\number);
                \denom = #1 / \gcd;
                % Build label text
                if \number < 0 then {
                    let \sign = -;
                } else {
                    let \sign =;
                };
                if \absnum == 1 then {
                    let \numpi = \pi;
                } else {
                    let \numpi = \absnum\pi;
                };
                if \denom == 1 then {
                    if \number == 0 then {
                        { \strut$0$ };
                    } else {
                        { \strut$\sign\numpi$ };
                    };
                } else {
                    { \strut$\sign\frac{\numpi}{\denom}$ };
                    % Other style with all pi symbols same and aligned:
                    %{ \strut$\sign\frac{\absnum}{\denom}\pi$ };
                };
            }
        },
    },
}

\printanswers
\graphicspath{ {./dir1/} }
\usepackage{hyperref}

\begin{document}

\begin{tikzpicture}
    \begin{axis}[
        width=14cm,
        axis equal image,
        domain=-2*pi:2*pi,
        axis lines=center,
        enlargelimits={abs=0.4},
        no markers,
        samples=100,
        ytick distance = 1,
        x axis in pi=2, % tick distance as fraction of pi
        ]
        \addplot {sin(x)};
    \end{axis}
\end{tikzpicture}

\end{document}

```

请帮忙。总之，解释错误并描述如何修复它（即保留\siunitx和代码）。

以下是使用 Overleaf 时遇到的错误的完整副本：

Compile Error. Sorry, your LaTeX code couldn't compile for some reason.
Please check the errors below for details, or view the raw log.
 test.tex, line 85
Missing \endcsname inserted.

<to be read again> 
                   \xparse function is not expandable 
l.85     \end{axis}
                   
The control sequence marked <to be read again> should
not appear between \csname and \endcsname.

 test.tex, line 85
Package siunitx Error: Invalid numerical input '='.

For immediate help type H <return>.
 ...                                              
                                                  
l.85     \end{axis}

 test.tex, line 85
Extra \endcsname.

\tikz@math@next ...math@parsed@keyword \endcsname 
                                                  \relax \expandafter \ifx \...
l.85     \end{axis}
                   
I'm ignoring this, since I wasn't doing a \csname.

 test.tex, line 85
Extra \endcsname.

\tikz@math@next ...math@parsed@keyword \endcsname 
                                                  \relax \tikz@math@error {U...
l.85     \end{axis}
                   
I'm ignoring this, since I wasn't doing a \csname.

 test.tex, line 85
Package tikz Error: tikz math library: Unknown function or keyword '\num ='.

See the tikz package documentation for explanation.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.85     \end{axis}
                   
This error message was generated by an \errmessage
command, so I can't give any explicit help.
Pretend that you're Hercule Poirot: Examine all clues,
and deduce the truth by order and method.

 test.tex, line 85
Package tikz Error: tikz math library: Unknown function or keyword '\num ='.

See the tikz package documentation for explanation.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.85     \end{axis}
                   
(That was another \errmessage.)

 test.tex, line 85
Package siunitx Error: Invalid numerical input '='.

For immediate help type H <return>.
 ...                                              
                                                  
l.85     \end{axis}
                   
(That makes 100 errors; please try again.) 
Here is how much of TeX's memory you used:
 37290 strings out of 480906
 871318 string characters out of 5908280
 1235087 words of memory out of 5000000
 52330 multiletter control sequences out of 15000+600000
 541835 words of font info for 55 fonts, out of 8000000 for 9000
 1141 hyphenation exceptions out of 8191
 73i,5n,127p,1576b,2023s stack positions out of 5000i,500n,10000p,200000b,80000s

 test.tex
==> Fatal error occurred, no output PDF file produced!

Answer 1

这里的主要问题似乎是使用已定义的宏作为内部变量。TikZ/pgf 有时倾向于将这些变量全球的因此这会在以后产生问题。

在这种情况下，\num来自siunitx并有望以某种方式行事。

使用\number也不是一个好主意，因为这是一个重要的 Plain TeX 宏。

对于此类临时变量，通常最好使用\myNumA等\myNumB方法来确保这些变量尚未被使用。