我正在使用 pgfplots 绘制图形，我想在绘制数据时修改横坐标值。我目前使用它x filter/.code={\pgfmathparse{1/#1} \pgfmathresult}来取 x 值的倒数。但是，对于这个数学运算，似乎缺乏精度。以下是 MWE，其中的输出不是所需的：
\documentclass[a4paper]{article}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
\begin{axis}[%
width=10cm,
height=5cm,
]
\addplot [x filter/.code={\pgfmathparse{1/#1} \pgfmathresult}]
table[row sep=crcr]{%
665.123474243553 50.0709210000000\\
665.124802332690 49.6678125000000\\
665.126130403923 49.7686245000000\\
665.127458480460 49.7501640000000\\
665.128786585510 49.6496310000000\\
665.130114672653 49.8061035000000\\
665.131442788313 50.1225825000000\\
665.132770886063 49.5357525000000\\
665.134099012330 49.4506110000000\\
665.135427120687 50.0079600000000\\
665.136755257560 49.0017465000000\\
665.138083376527 49.5523995000000\\
665.139411524010 49.7646720000000\\
665.140739653583 49.7826210000000\\
665.142067788460 49.3249215000000\\
665.143395951857 48.9346470000000\\
665.144724097340 48.6674580000000\\
665.146052271343 48.2280330000000\\
665.147380427437 46.8564690000000\\
665.148708612050 46.2079800000000\\
665.150036778750 44.7215610000000\\
665.151364973970 44.2429365000000\\
665.152693151283 43.3782690000000\\
665.154021357110 44.1923910000000\\
665.155349545030 44.8409730000000\\
665.156677761467 45.3737235000000\\
665.158005959997 46.7979255000000\\
665.159334163827 47.2520910000000\\
665.160662396177 48.7288845000000\\
665.161990610620 48.5122410000000\\
665.163318853580 49.2502890000000\\
665.164647078630 48.5547885000000\\
665.165975332200 49.2531720000000\\
665.167303567860 50.3161155000000\\
665.168631832037 49.4624685000000\\
665.169960078307 49.6258695000000\\
665.171288353093 50.0582730000000\\
665.172616609973 49.7700195000000\\
665.173944872157 49.7608590000000\\
665.175273162857 49.8229830000000\\
665.176601435650 49.8743190000000\\
665.177929736963 49.8491160000000\\
};
\end{axis}
\end{tikzpicture}
\end{document}
有没有什么办法可以提高精度呢？
编辑解决方案：
\documentclass[a4paper]{article}
\usepackage{pgfplots,xfp}
\begin{document}
\begin{tikzpicture}
\begin{axis}[%
width=10cm,
height=5cm,
xticklabel style={/pgf/number format/fixed,/pgf/number format/precision=6, rotate=45}
]
\addplot [x filter/.code={\def\pgfmathresult{\fpeval{1/#1}}}]
table[row sep=crcr]{%
665.123474243553 50.0709210000000\\
665.124802332690 49.6678125000000\\
665.126130403923 49.7686245000000\\
665.127458480460 49.7501640000000\\
665.128786585510 49.6496310000000\\
665.130114672653 49.8061035000000\\
665.131442788313 50.1225825000000\\
665.132770886063 49.5357525000000\\
665.134099012330 49.4506110000000\\
665.135427120687 50.0079600000000\\
665.136755257560 49.0017465000000\\
665.138083376527 49.5523995000000\\
665.139411524010 49.7646720000000\\
665.140739653583 49.7826210000000\\
665.142067788460 49.3249215000000\\
665.143395951857 48.9346470000000\\
665.144724097340 48.6674580000000\\
665.146052271343 48.2280330000000\\
665.147380427437 46.8564690000000\\
665.148708612050 46.2079800000000\\
665.150036778750 44.7215610000000\\
665.151364973970 44.2429365000000\\
665.152693151283 43.3782690000000\\
665.154021357110 44.1923910000000\\
665.155349545030 44.8409730000000\\
665.156677761467 45.3737235000000\\
665.158005959997 46.7979255000000\\
665.159334163827 47.2520910000000\\
665.160662396177 48.7288845000000\\
665.161990610620 48.5122410000000\\
665.163318853580 49.2502890000000\\
665.164647078630 48.5547885000000\\
665.165975332200 49.2531720000000\\
665.167303567860 50.3161155000000\\
665.168631832037 49.4624685000000\\
665.169960078307 49.6258695000000\\
665.171288353093 50.0582730000000\\
665.172616609973 49.7700195000000\\
665.173944872157 49.7608590000000\\
665.175273162857 49.8229830000000\\
665.176601435650 49.8743190000000\\
665.177929736963 49.8491160000000\\
};
\end{axis}
\end{tikzpicture}
\end{document}
答案1
使用 xfp 我得到了这个
\documentclass[a4paper]{article}
\usepackage{pgfplots,xfp}
\begin{document}
\begin{tikzpicture}
\begin{axis}[%
width=10cm,
height=5cm,
]
\addplot [x filter/.code={\fpeval{1/#1}}]
table[row sep=crcr]{%
665.123474243553 50.0709210000000\\
665.124802332690 49.6678125000000\\
665.126130403923 49.7686245000000\\
665.127458480460 49.7501640000000\\
665.128786585510 49.6496310000000\\
665.130114672653 49.8061035000000\\
665.131442788313 50.1225825000000\\
665.132770886063 49.5357525000000\\
665.134099012330 49.4506110000000\\
665.135427120687 50.0079600000000\\
665.136755257560 49.0017465000000\\
665.138083376527 49.5523995000000\\
665.139411524010 49.7646720000000\\
665.140739653583 49.7826210000000\\
665.142067788460 49.3249215000000\\
665.143395951857 48.9346470000000\\
665.144724097340 48.6674580000000\\
665.146052271343 48.2280330000000\\
665.147380427437 46.8564690000000\\
665.148708612050 46.2079800000000\\
665.150036778750 44.7215610000000\\
665.151364973970 44.2429365000000\\
665.152693151283 43.3782690000000\\
665.154021357110 44.1923910000000\\
665.155349545030 44.8409730000000\\
665.156677761467 45.3737235000000\\
665.158005959997 46.7979255000000\\
665.159334163827 47.2520910000000\\
665.160662396177 48.7288845000000\\
665.161990610620 48.5122410000000\\
665.163318853580 49.2502890000000\\
665.164647078630 48.5547885000000\\
665.165975332200 49.2531720000000\\
665.167303567860 50.3161155000000\\
665.168631832037 49.4624685000000\\
665.169960078307 49.6258695000000\\
665.171288353093 50.0582730000000\\
665.172616609973 49.7700195000000\\
665.173944872157 49.7608590000000\\
665.175273162857 49.8229830000000\\
665.176601435650 49.8743190000000\\
665.177929736963 49.8491160000000\\
};
\end{axis}
\end{tikzpicture}
\end{document}