从新行开始提升方程编号位置

Question

我正在尝试在多列环境中编写一个方程式，尽管最后一行有方程式编号的空间，但 LaTeX 似乎将其放在了新行上。

\documentclass[a4paper, 12pt]{article}
\usepackage{lipsum, amsmath, multicol, geometry}
\geometry{left=20mm, right=20mm, top=20mm, bottom=20mm}
\begin{document}
\begin{multicols}{2}
Using central differences for the first and second order derivative our numerical scheme becomes
\begin{equation}
\begin{aligned}
h_j^{n+1} =  h_j^n &+  \dfrac{\Delta t \left(h_j^n\right)^3}{(\Delta x)^2} 
\left(h_{j+1}^n - 2 h_j^n + h_{j-1}^n\right)\\ 
&+  \dfrac{3\Delta t \left(h_j^n\right)^2}{4(\Delta x)^2} 
\left(h_{j+1}^n - h_{j-1}^n\right)
\end{aligned}
\label{eqt:numerical_scheme}
\end{equation}
where we notice something\\
\lipsum[2]
\end{multicols}
\end{document}

给出以下内容：

我希望方程式编号在有空间的最后一行更高。我尝试过交换行和各种环境，但没有成功。

任何帮助，将不胜感激。

Answer 1

\documentclass{article}
\usepackage{multicol,amsmath}
\addtolength\textwidth{2cm}
\begin{document}

\begin{multicols}{2}
Using central differences for the first and second order derivative our numerical scheme becomes
\begin{gather}
\begin{aligned}
h_j^{n+1} =  h_j^n &+  \dfrac{\Delta t \left(h_j^n\right)^3}{(\Delta x)^2} 
\left(h_{j+1}^n - 2 h_j^n + h_{j-1}^n\right)\\ 
&+  \dfrac{3\Delta t \left(h_j^n\right)^2}{4(\Delta x)^2} 
\left(h_{j+1}^n - h_{j-1}^n\right)
\end{aligned}
\label{eqt:numerical_scheme1}
\raisetag{20pt}
\end{gather}
where we notice something

Using central differences for the first and second order derivative our numerical scheme becomes
\begin{align}
h_j^{n+1} =  h_j^n &+  \dfrac{\Delta t \left(h_j^n\right)^3}{(\Delta x)^2} 
\left(h_{j+1}^n - 2 h_j^n + h_{j-1}^n\right)\nonumber\\ 
&+  \dfrac{3\Delta t \left(h_j^n\right)^2}{4(\Delta x)^2} 
\left(h_{j+1}^n - h_{j-1}^n\right)
\label{eqt:numerical_scheme2}
\end{align}
where we notice something

\end{multicols}

\end{document}

请始终发布完整的文档，我不得不猜测文本宽度才能获得您显示的效果。您可以使用\raisetag（但显然不是，equation所以我使用了一行gather）或者您可以使用align并只编号一行。

Answer 2

另一个选项使用align：

\documentclass[12pt]{article}
\setlength\textwidth{19.18em} 
\usepackage{amsmath,microtype}
\newcommand\ddfrac[2]{\frac{\displaystyle#1}{\displaystyle#2}}

\begin{document}
\noindent differences for the first and second order derivatives 
our numerical scheme becomes
\begin{align}
h_j^{n+1} = h_j^n &+ \ddfrac{\Delta t(h_j^n)^3}{(\Delta x)^2} 
\bigl(h_{j+1}^n - 2h_j^n + h_{j-1}^n\bigr) \notag \\ 
& + \ddfrac{3\Delta t(h_j^n)^2}{4(\Delta x)^2} 
\bigl(h_{j+1}^n - h_{j-1}^n \bigr) \label{eqt:numerical_scheme2} 
\end{align}
where we notice something

\end{document}

Answer 3

这是另一种方法，使用可选参数aligned和\mathrlap：

\documentclass{article}
\usepackage{multicol,mathtools, lipsum}
\addtolength\textwidth{2cm}
\begin{document}

\begin{multicols}{2}
  Using central differences for the first and second order derivative our numerical scheme becomes
  \begin{equation}
    \begin{aligned}[b]
      h_j^{n+1} =h_j^n & + \dfrac{Δt \left(h_j^n\right)³}{(Δx)²}
      \bigl(h_{j+1}^n - 2 h_j^n +\mathrlap{ h_{j-1}^n\bigr)} \\
                       & +\dfrac{3Δt \left(h_j^n\right)²}{4(Δx)²}
      \left(h_{j+1}^n - h_{j-1}^n\right)
    \end{aligned}
    \label{eqt:numerical_scheme1}
  \end{equation}
  where we notice something.

  \lipsum[11]

\end{multicols}

\end{document} 

Answer 4

multline对于手头的材料，可以通过使用环境而不是嵌套equation和环境来简单地避免方程式编号放置问题aligned。这两个+符号的垂直对齐在这里似乎不是一个引人注目的目标。

\documentclass{article}
\setlength\textwidth{2.75in} % an educated guess...
\usepackage{amsmath}
% a version of \frac that uses \displaystyle for numerator and deminator:
\newcommand\ddfrac[2]{\frac{\displaystyle#1}{\displaystyle#2}}

\begin{document}
Using central differences for the first and second 
order derivatives our numerical scheme becomes
\begin{multline}
h_j^{n+1} =  h_j^n 
+ \ddfrac{\Delta t(h_j^n)^3}{(\Delta x)^2} 
   \bigl(h_{j+1}^n - 2h_j^n + h_{j-1}^n\bigr)\\ 
+  \ddfrac{3\Delta t(h_j^n)^2}{4(\Delta x)^2} 
   \bigl(h_{j+1}^n - h_{j-1}^n \bigr) 
\label{eqt:numerical_scheme2} 
\end{multline}
where we notice something
\end{document}