正如标题所示，我有一个包含多个单元格的方程式，我希望每个单元格的内容都左对齐。以下这个答案我尝试过，flalign但是这似乎只是将整个方程式左对齐。以下是一个小例子：
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{flalign*}
\textrm{Some stuff about } \rho & & \\
\qquad \textrm{This is a really long equation and the following} \qquad & \textrm{should be left aligned} & \\
\qquad \textrm{Short equation (should be left too)} \qquad & \textrm{but quite a long one on the right though} &
\end{flalign*}
\end{document}
此示例产生以下输出（我加了一些注释以表明我想要实现的目标）：
经过一番研究，我感觉这些 二方法应该可以，但我无法让它发挥作用。
继首次接近我试过：
\documentclass{article}
\usepackage{amsmath}
\usepackage{calc}
\newcommand*{\mbc}[2]{\makebox[\widthof{$F(\alpha)$}][#1]{$#2$}}
\begin{document}
\begin{flalign*}
\mbc{l}{\textrm{Some stuff about } \rho} & & \\
\qquad \textrm{This is a really long equation and the following} \qquad & \textrm{should be left aligned} & \\
\qquad \textrm{Short equation (should be left too)} \qquad & \textrm{but quite a long one on the right though} &
\end{flalign*}
\end{document}
令人惊讶的是，第一行现在似乎出现在第二个单元格中（而不是在第一个单元格中左对齐）：
这第二种方法似乎不适用于数学符号：
\documentclass{article}
\usepackage{amsmath}
\newcommand{\pushleft}[1]{\ifmeasuring@#1\else\omit$\displaystyle#1$\hfill\fi\ignorespaces}
\begin{document}
\begin{flalign*}
\pushleft{\textrm{Some stuff about } \rho} & & \\
\qquad \textrm{This is a really long equation and the following} \qquad & \textrm{should be left aligned} & \\
\qquad \textrm{Short equation (should be left too)} \qquad & \textrm{but quite a long one on the right though} &
\end{flalign*}
\end{document}
给出输出：
$ pdflatex test.tex
[...]
! Undefined control sequence.
\pushleft #1->\ifmeasuring
@#1\else \omit $\displaystyle #1$\hfill \fi \igno...
l.20 \end{flalign*}
插入额外的$$也无济于事。我能得到的最接近的方法是使用\omit和，\hfill但是\omit似乎选择退出数学模式，所以我需要插入额外的$$：
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{flalign*}
\omit $\textrm{Some stuff about } \rho$ \hfill & & \\
\omit $\qquad \textrm{This is a really long equation and the following} \qquad$ \hfill & \textrm{should be left aligned} & \\
\omit $\qquad \textrm{Short equation (should be left too)} \qquad$ \hfill & \textrm{but quite a long one on the right though} &
\end{flalign*}
\end{document}
$$它确实有效，但是我的 IDE到处将多余的内容标记为错误，这绝对令人不快。另外，我不确定这是否是一个干净的解决方案，并且始终能按预期工作。
有人知道如何在包含数学符号的方程式中实现单元格左对齐吗？或者对后一种\omit方法有\hfill什么评论$$？
答案1
像这样？
\documentclass{article}
\usepackage{mathtools}
\usepackage[showframe]{geometry}
\begin{document}
\begin{flalign*}
& \textrm{Some stuff about } \rho & & \\
& \qquad \textrm{This is a really long equation and the following} && \textrm{should be left aligned} \\
& \qquad \textrm{Short equation (should be left too)} & & \textrm{but quite a long one on the right though}
\end{flalign*}
\end{document}
其他对齐的示例代码：
\documentclass{article}
\usepackage{mathtools}
\usepackage[showframe]{geometry}
\begin{document}
\begin{flalign*}
\shortintertext{\texttt{Columns left-aligned:} }
& \textrm{Some stuff about } \rho \\
& \qquad \textrm{This is a really long equation and the following} && \textrm{should be left aligned} \\
& \qquad \textrm{Short equation (should be left too)} & & \textrm{but quite a long one on the right though}
\end{flalign*}
\begin{flalign*}
\shortintertext{\texttt{Columns right-aligned:} }
& \rlap{Some stuff about $\rho $} \\
& & \textrm{This is a really long equation and the following}& & \textrm{should be right aligned}& \\
& &\textrm{Short equation (should be rightt too)} && \textrm{but quite a long one on the right though}&
\end{flalign*}
\begin{flalign*}
\shortintertext{\texttt{Left column centred, right column left-aligned: }}
& \textrm{Some stuff about } \rho \\
& \begin{gathered} \textrm{This is a really long equation and the following}\\\textrm{Short equation (should be centred)}\end{gathered}
& \begin{aligned} & \textrm{should be left aligned} \\
& \textrm{but quite a long one on the right though}\end{aligned}&
\end{flalign*}
\end{document}
