等式中的警告

Question

我插入了以下方程式：

\begin{subequations}
    \begin{align}   
        \rho(\bm{z}) = \bm{z}; 
        \label{eq.:Rho(z)=z} \\
        \bm{x}(\bm{z}) = \epsilon + (1 - \epsilon){\bm{z}}^p, & \quad \text{for } p \geqslant 1
        \label{eq.:SIMP}
    \end{align}
\end{subequations}

\begin{equation}
    \overline{\bm{z}} = \frac{\tanh\left(\beta\eta\right) + \tanh\left(\beta\left(\bm{z} - \eta\right)\right)}{\tanh\left(\beta\eta\right) + \tanh\left(\beta\left(1 - \eta\right)\right)}
    \label{eq.:HeavisideFnc}
\end{equation}

我收到了这条没有任何信息的警告信息：

我正在使用这两个包：

\usepackage{amsmath,amsfonts,amssymb} 
\usepackage{bm} 

日志文件中有这些警告：

Chapter 3.
<Imagens/Design_Domain.pdf, id=754, 262.73157pt x 184.43906pt>
File: Imagens/Design_Domain.pdf Graphic file (type pdf)

<use Imagens/Design_Domain.pdf>
Package pdftex.def Info: Imagens/Design_Domain.pdf used on input line 13.
(pdftex.def)             Requested size: 210.18552pt x 147.55144pt.
 [26

 <./Imagens/Design_Domain.pdf>] [27pdfTeX warning (ext4): destination with the 
same identifier (name{equation.3.2.1}) has been already used, duplicate ignored

    \AtBegShi@Output ...ipout \box \AtBeginShipoutBox 
                                                      \fi \fi 
    l.51 
         ] <Imagens/SIMP.pdf, id=800, 392.96812pt x 322.95656pt>
    File: Imagens/SIMP.pdf Graphic file (type pdf)

    <use Imagens/SIMP.pdf>
    Package pdftex.def Info: Imagens/SIMP.pdf used on input line 54.
    (pdftex.def)             Requested size: 392.96715pt x 322.95576pt.
    pdfTeX warning (ext4): destination with the same identifier (name{equation.3.2.
    2}) has been already used, duplicate ignored
    <to be read again> 
                       \relax 
    l.63 \begin{equation}
                          [28 <./Imagens/SIMP.pdf>]

“.log”文件显示我插入了两次相同的方程式，但我没有。

可以看到，equation.3.2.1 是使用subequations文件 3.2.1 小节中的包创建的此文件的第一个方程.tex，而 equation.3.2.2 是它的第二个方程。在 3.2.2 节中，我定义了另一个方程，它也被标记为 equation.3.2.2，导致 latex 中出现此警告。

最后，该.aux文件包含以下内容：

\@writefile{toc}{\contentsline {section}{\numberline {3.2}Material Model}{27}{section.3.2}}
\newlabel{sec.:Model}{{3.2}{27}{Material Model}{section.3.2}{}}
\@writefile{toc}{\contentsline {subsection}{\numberline {3.2.1}Solid Isotropic Material with Penalization (SIMP)}{27}{subsection.3.2.1}}
\newlabel{subsec.:SIMP}{{3.2.1}{27}{Solid Isotropic Material with Penalization (SIMP)}{subsection.3.2.1}{}}
\newlabel{eq.:Rho(z)=z}{{3.1a}{27}{Solid Isotropic Material with Penalization (SIMP)}{equation.3.2.1}{}}
\newlabel{eq.:SIMP}{{3.1b}{27}{Solid Isotropic Material with Penalization (SIMP)}{equation.3.2.2}{}}
\citation{Leitao_et_al2018}
\citation{Lahuerta2012}
\citation{Lahuerta2012}
\@writefile{toc}{\contentsline {subsection}{\numberline {3.2.2}Heaviside Projection Function}{28}{subsection.3.2.2}}
\newlabel{subsec.:Heaviside_Fnc}{{3.2.2}{28}{Heaviside Projection Function}{subsection.3.2.2}{}}
\newlabel{eq.:HeavisideFnc}{{3.2}{28}{Heaviside Projection Function}{equation.3.2.2}{}}

我曾尝试修复此问题，但不知道该如何解决。有人知道如何解决吗？谢谢您的建议。

Answer 1

您可能hyperref在加载之前就加载了amsmath。然后hyperref无法在某些环境下正常工作amsmath。为了避免此类问题，

\usepackage{hyperref}

应始终位于其他\usepackage语句之后。

例如

\documentclass{article}
\usepackage{amsmath,amsfonts,amssymb}
\usepackage{bm}
\usepackage{hyperref}
\begin{document}
\begin{subequations}
    \begin{align}   
        \rho(\bm{z}) = \bm{z}; 
        \label{eq.:Rho(z)=z} \\
        \bm{x}(\bm{z}) = \epsilon + (1 - \epsilon){\bm{z}}^p, & \quad \text{for } p \geqslant 1
        \label{eq.:SIMP}
    \end{align}
\end{subequations}

\begin{equation}
    \overline{\bm{z}} = \frac{\tanh\left(\beta\eta\right) + \tanh\left(\beta\left(\bm{z} - \eta\right)\right)}{\tanh\left(\beta\eta\right) + \tanh\left(\beta\left(1 - \eta\right)\right)}
    \label{eq.:HeavisideFnc}
  \end{equation}
\end{document}

正常工作，而

\documentclass{article}
\usepackage{hyperref}% -- BAD! Too early, hyperref should be last
\usepackage{amsmath,amsfonts,amssymb}
\usepackage{bm}
\begin{document}
\begin{subequations}
    \begin{align}   
        \rho(\bm{z}) = \bm{z}; 
        \label{eq.:Rho(z)=z} \\
        \bm{x}(\bm{z}) = \epsilon + (1 - \epsilon){\bm{z}}^p, & \quad \text{for } p \geqslant 1
        \label{eq.:SIMP}
    \end{align}
\end{subequations}

\begin{equation}
    \overline{\bm{z}} = \frac{\tanh\left(\beta\eta\right) + \tanh\left(\beta\left(\bm{z} - \eta\right)\right)}{\tanh\left(\beta\eta\right) + \tanh\left(\beta\left(1 - \eta\right)\right)}
    \label{eq.:HeavisideFnc}
  \end{equation}
\end{document}

导致您注意到警告。