[Tex/LaTex] Custom pagebreak in align equation

alignequationspage-breakingvertical alignment

I got the following problem: Right now I am checking my equations, which are usually written in align. This looks great in most of the cases, but sometimes the pagebreaks are weird, ie there is a lot of vertical whitespace left (like 2.5cm) at the end of a page. I made the following MWE to illustrate this.

\documentclass[a4paper, 12pt, headsepline]{scrreprt}
\usepackage[onehalfspacing]{setspace}
\usepackage{amsmath, amssymb, mathtools}
\usepackage{mathptmx}
\usepackage[a4paper]{geometry}
\geometry{left=2cm,right=5cm,top=2cm,bottom=2cm}
% \usepackage{lipsum} %\lipsum
\usepackage[pangram]{blindtext}

\begin{document}
\Blindtext[1][3]%1 paragraph, 3 pangrams
\begin{align}
X_{t+1} &=  \frac{X_{t+1}+X_{t+1}}{Y_t}  \label{eq:1} 
\intertext{Solving...:} \notag 
X_{t}  &=  \frac{X_{t+1}+X_{t+1}}{Y_{t+1}} \notag \\
\intertext{Solving further...:} \notag 
% ===PAGEBREAK HERE: 2nd page begins===
&= \frac{X_{t+1}+X_{t+1}}{Y_t} + 
\frac{X_{t+1}+X_{t+1}}{Y_t}  \notag \\
&= \frac{X_{t+1}+X_{t+1}}{Y_t}...  \notag \\
\intertext{Solving further...:} & = \frac{X_{t+1}+X_{t+1}}{Y_t}  \notag
\end{align} 
\end{document}

In the MWE, the first 'Solving further' should be on the first page instead (to save space and it would also look better I guess?). The position where I would like the pagebreak to be is also marked as a comment in the MWE.

My question is first on a general basis: Which is the best environment to achieve multiple line equations, which can be aligned as in align, and to save space at the same time? Or to be more precise: If possible, I'd like to stick with align and adapt the pagebreaks only if necessary.

Thanks!

Best Answer

If you want automatic page breaks you have to use the command \allowdisplaybreaks in your preamble.

If you want manual page breaks, you have to use the command \displaybreak followed by \\, as in the following MWE:

\documentclass[a4paper, 12pt, headsepline]{scrreprt}
\usepackage[onehalfspacing]{setspace}
\usepackage{amsmath, amssymb, mathtools}
\usepackage{mathptmx}
\usepackage[a4paper]{geometry}
\geometry{left=2cm,right=5cm,top=2cm,bottom=2cm}
% \usepackage{lipsum} %\lipsum
\usepackage[pangram]{blindtext}

\begin{document}
\Blindtext[1][3]%5 paragraphs, each 3 pangrams
\begin{align}
X_{t+1} &=  \frac{X_{t+1}+X_{t+1}}{Y_t}  \label{eq:1}
\intertext{Solving...:} \notag
X_{t}  &=  \frac{X_{t+1}+X_{t+1}}{Y_{t+1}} \notag \\
\intertext{Solving further...:} \notag \displaybreak\\
% ===PAGEBREAK HERE: 2nd page begins===
&= \frac{X_{t+1}+X_{t+1}}{Y_t} +
\frac{X_{t+1}+X_{t+1}}{Y_t}  \notag \\
&= \frac{X_{t+1}+X_{t+1}}{Y_t}...  \notag \\
\intertext{Solving further...:} & = \frac{X_{t+1}+X_{t+1}}{Y_t}  \notag
\end{align}
\end{document}

Output

enter image description here

Related Solutions

[Tex/LaTex] \pagebreak vs \newpage

Both commands start a new page.

If the optional argument is not used, \pagebreak will start a new page and the paragraphs of the old page will be spread out so that the old page will not look like the end of a chapter.

With \newpage, on the other hand, the old page will have the blank space at the bottom, because the paragraphs will stick together as if the chapter had ended there.

This link will be useful, and the answer to a duplicate question (that was migrated from SO to this site later) gives the following example: alt text

[Tex/LaTex] Align equation left

I would not use the equation environment; rather, I would use flalign as such:
(notice the && at the end of each line)

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\noindent A \hfill Z
\begin{flalign}
a_{ijk} &= \frac {Pr(M_{I} =2  \&  M_J=1 \& M_K =1 | I=i , J=j , K=k)}{Pr (M_I =1 \& M_J =1 \& M_K=1 | I=i , J=j)}&&\\\nonumber
            &= \frac {\mu_{ijk211}}{\mu_{ijk111}}&&
\end{flalign}

\noindent A \hfill Z
\end{document}

Output

Another way to go is to set the fleqn option for the document class. However, this left-aligns all of your equations and hence should not be used when you want at least some equations to remain centered.

\documentclass[fleqn]{article}
\usepackage{amsmath}
\begin{document}
\noindent A \hfill Z
\begin{equation}
\begin{aligned}
a_{ijk} &= \frac {Pr(M_{I} =2  \&  M_J=1 \& M_K =1 | I=i , J=j , K=k)}{Pr (M_I =1 \& M_J =1 \& M_K=1 | I=i , J=j)}\\
            &= \frac {\mu_{ijk211}}{\mu_{ijk111}}\\
\end{aligned}
\end{equation}
\noindent A \hfill Z
\end{document}

For this output:

Output 2

As suggested by karlkoeller, if you want to get rid of the space between the left margin and the equation (to get a result similar to the first case), you should add \setlength{\mathindent}{0pt}. If you later want to indent it back to its default value, you can use the same command with a value of 15pt, which is the amount of pt a paragraph indent shifts its text to the right.

Best Answer

Related Solutions

[Tex/LaTex] \pagebreak vs \newpage

[Tex/LaTex] Align equation left

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