将文档中的所有等号对齐

Question

有没有办法让整个文档中所有等式的所有等号对齐？我写了一个论文（scrbook），希望所有等号都对齐。如果无法让整个文档对齐，至少在一章中对齐。

或者\begin{align}只\begin{eqnarray}针对小组这样做。而用于\intertext整个章节是不切实际的。

例如目前的情况：

\begin{align}    
F_L^{\rightarrow}   & =     q ( E_{eFeld}^{\rightarrow} + v^{\rightarrow} \times B^{\rightarrow} )
    \end{align}

much text

    \begin{align}
    F_{Lx}  & =     q ( E_{eFeld} + v_{gx} * B )
    \end{align}

    little text

    \begin{align}
    T   & =     F_{L1} - F_{L2}                                         \\
        & =     q ( E_{eFeld} + v_{g1} * B - E_{eFeld} - v_{g2} * B )   \\
        & =     q*B ( v_{g1} - v_{g2} )         
    \end{align}                     

    \subsection{new subsection}

    very little text

    \begin{align}
    P_{Photon}  & =     hf * nAc                \\
                & =     \frac{E_{Photon}}{t}    
    \end{align}

    more text

    \begin{align}
    F_{0}       & =     2nhfA               \\
                & =     \frac{2 P_{Photon}}{c}  
    \end{align}

我想要的是类似这样的东西：

A  = b+C

Text

A  = longe equation

**New Headline**

B  = also nice equation

等等。我想你明白我想要什么了。你能帮我吗？谢谢

Answer 1

从我的回答开始对齐单独的方程式，我发现我需要更改一些内容，特别是因为这个问题的 OP 想要包含多线方程。因此，我必须将其恢复\arraystretch为非零值（事实上，我将其设置为 1.2）。但这样一来，我必须\vspace在进入和退出algneqn我创建的环境时进行一些操作。

但最终，所有等号都对齐了，正如 OP 所要求的。设置\leftalgn和的值\rightalgn将决定对齐标签将设置在整行的哪个位置。

\documentclass{article}
\usepackage{amsmath}
\def\leftalgn{0.3}\def\rightalgn{0.6}
\def\algnrow{\rule{\leftalgn\textwidth}{0ex}&\rule{\rightalgn\textwidth}{0ex}}
% CONSTRAINTS:
% equation label must fit in {1 -\leftalgn -\rightalgn}\textwidth
% \leftalgn must be larger than any text to left of align character
% \rightalgn must be larger than any text to right of align character
\newenvironment{algneqn}{%
  \vspace{-1.6\baselineskip}%
  \arraycolsep=0ex\renewcommand\arraystretch{1.2}%
  \begin{equation}%
  \begin{array}{rl}%
  \algnrow\\%
}%
 {\\\algnrow%
  \end{array}\vspace{-\baselineskip}%
  \end{equation}\ignorespacesafterend%
}
\def\snug#1{\vspace*{-#1\baselineskip}}
\begin{document}
\begin{algneqn}    
F_L^{\rightarrow}   & =     q ( E_{eFeld}^{\rightarrow} + v^{\rightarrow} \times B^{\rightarrow} )
    \end{algneqn}

much text

    \begin{algneqn}
    F_{Lx}  & =     q ( E_{eFeld} + v_{gx} * B )
    \end{algneqn}

    little text

    \begin{algneqn}
    T   & =     F_{L1} - F_{L2}                                         \\
        & =     q ( E_{eFeld} + v_{g1} * B - E_{eFeld} - v_{g2} * B )   \\
        & =     q*B ( v_{g1} - v_{g2} )         
    \end{algneqn}                     

    \subsection{new subsection}

    very little text

    \begin{algneqn}
    P_{Photon}  & =     hf * nAc                \\
                & =     \dfrac{E_{Photon}}{t}    
    \end{algneqn}

    more text

    \begin{algneqn}
    F_{0}       & =     2nhfA               \\
                & =     \dfrac{2 P_{Photon}}{c}  
    \end{algneqn}
\end{document}