\underbrace spanning multiple lines
pech...@cs.technion.ac.il
lines. I'd like to do something like
\begin{equation}
\begin{split}
A = & \underbrace{ B + \\
& C +}_{xxx} \\
& D
\end{split}
\end{equation}
but it does not pass Latex compilation.
Thanks in advance,
Dmitry Pechyony
Lars Madsen
the above does of course not work because of the line breaks.
Here is a proof of concept showing that it could be done
\documentclass{article}
\usepackage{mathtools} % auto loads amsmath
\begin{document}
\begin{equation}
\begin{split}
a &= b +c +g +r_q \\
&\quad \underbrace{
\mathmakebox[\widthof{$\displaystyle b +c +g +r_q$}][l]{
+ x+y}}_{xxx}
\end{split}
\end{equation}
\end{document}
It not optimized at all, just showing that it can be done
--
/daleif (remove RTFSIGNATURE from email address)
LaTeX FAQ: http://www.tex.ac.uk/faq
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Remember to post minimal working examples.
pech...@cs.technion.ac.il
math lines. The underbrace symbol itself occupies single line. My
question is whether the single underbrace symbol may occupy several
lines.
Jean-Côme Charpentier
I don't understand. One can define \underbraceleft, \underbraceright
(even \underbracemiddle) macros. But where put your _{xxx} (first
line, second one, split, other)?
Jean-Côme Charpentier
pech...@cs.technion.ac.il
symbol should occupy, and in general it should be somewhere in the
middle.
If we have two lines, then _{xxx} should be at the end of the first
line (or at the start of the second line). If we have three lines then
_{xxx} should be in the middle of the second line.
How do you define the macros \underbraceleft, \underbraceright,
\underbracemiddle?
Dan
pech...@cs.technion.ac.il wrote:
> The placement of _{xxx} depends on the number of lines that underbrace
> symbol should occupy, and in general it should be somewhere in the
> middle.
> If we have two lines, then _{xxx} should be at the end of the first
> line (or at the start of the second line). If we have three lines then
> _{xxx} should be in the middle of the second line.
Such a design would seem to be confusing at best and misleading at
worst (and probably hideous to look at). I wouldn't even try to
implement it, but rather would find some other way to label/describe
that group of items.
Can you point to an existing book or article that uses something like
that?
Dan
Jean-Côme Charpentier
> pech...@cs.technion.ac.il wrote:
>
>>The placement of _{xxx} depends on the number of lines that underbrace
>>symbol should occupy, and in general it should be somewhere in the
>>middle.
>>If we have two lines, then _{xxx} should be at the end of the first
>>line (or at the start of the second line). If we have three lines then
>>_{xxx} should be in the middle of the second line.
>
>
> Such a design would seem to be confusing at best and misleading at
> worst (and probably hideous to look at).
I'm agree with you but the challenge was funny (even the result is
horrible) :-)
\documentclass{article}
\makeatletter
\newcommand*\Lupbracefill{%
$\m@th
\setbox\z@ \hbox{$\braceld$}%
\bracelu
\leaders \vrule \@height \ht\z@ \@depth \z@ \hfill
$%
}
\newcommand*\LMupbracefill{%
$\m@th
\setbox\z@ \hbox{$\braceld$}%
\bracelu
\leaders \vrule \@height \ht\z@ \@depth \z@ \hfill
\bracerd
\braceld
\leaders \vrule \@height \ht\z@ \@depth \z@ \hfill
$%
}
\newcommand*\Mupbracefill{%
$\m@th
\setbox\z@ \hbox{$\braceld$}%
\leaders \vrule \@height \ht\z@ \@depth \z@ \hfill
\bracerd
\braceld
\leaders \vrule \@height \ht\z@ \@depth \z@ \hfill
$%
}
\newcommand*\MRupbracefill{%
$\m@th
\setbox\z@ \hbox{$\braceld$}%
\leaders \vrule \@height \ht\z@ \@depth \z@ \hfill
\bracerd
\braceld
\leaders \vrule \@height \ht\z@ \@depth \z@ \hfill
\braceru
$%
}
\newcommand*\Rupbracefill{%
$\m@th
\setbox\z@ \hbox{$\braceld$}%
\leaders \vrule \@height \ht\z@ \@depth \z@ \hfill
\braceru
$%
}
\newcommand*\Eupbracefill{%
$\m@th
\setbox\z@ \hbox{$\braceld$}%
\leaders \vrule \@height \ht\z@ \@depth \z@ \hfill
$%
}
\newcommand*\Allunderbrace[2]{%
\mathop{%
\vtop {%
\m@th
\ialign{%
##\crcr $\hfil \displaystyle {#2}\hfil$\crcr
\noalign{\kern 3\p@ \nointerlineskip}%
#1 \crcr
\noalign{\kern 3\p@}%
}%
}%
}\limits
}
\newcommand*\Lunderbrace{%
\Allunderbrace\Lupbracefill
}
\newcommand*\LMunderbrace{%
\Allunderbrace\LMupbracefill
}
\newcommand*\Munderbrace{%
\Allunderbrace\Mupbracefill
}
\newcommand*\MRunderbrace{%
\Allunderbrace\MRupbracefill
}
\newcommand*\Runderbrace{%
\Allunderbrace\Rupbracefill
}
\newcommand*\Eunderbrace{%
\Allunderbrace\Eupbracefill
}
\newcommand*\splitunderbrace[1]{%
\def\splitformula{#1}%
\@ifnextchar_{\split@underbrace}{\split@@underbrace}
}
\newif\ifsub
\def\split@underbrace_#1{%
\def\splitsub{#1}%
\subtrue
\split@@@underbrace
}
\def\split@@underbrace{%
\subfalse
\split@@@underbrace
}
\newcommand\split@@@underbrace{%
\count@=0
%% count@ = nb lines
\expandafter\SU@countbs\splitformula \\\@nil
\ifcase\count@
% impossible
\or
\ifsub
\underbrace{\splitformula}_{\splitsub}%
\else
\underbrace{\splitformula}%
\fi
\or
% 2
\setbox0=\hbox{$\displaystyle\@nameuse{SF@0}\phantom{\braceld}$}%
\setbox1=\hbox{$\displaystyle\@nameuse{SF@1}\phantom{\braceld}$}%
\ifdim\wd0>\wd1
\ifsub
\LMunderbrace{\box0}_{\splitsub}\\
\Runderbrace{\box1}%
\else
\Lunderbrace{\box0}\\
\MRunderbrace{\box1}%
\fi
\else
\ifsub
\else
\fi
\fi
\else
% >=3
\@tempcnta=\count@
\divide\@tempcnta \tw@
\ifodd\count@
% nb line is odd (one middle)
\advance\count@ \m@ne
% very left part
\setbox0=\hbox{$\displaystyle\@nameuse{SF@0}\phantom{\braceld}$}%
\Lunderbrace{\box0}\\
\@tempcntb=\@ne
% left parts
\loop
\ifnum\@tempcntb<\@tempcnta
\setbox0=\hbox{%
$\displaystyle\@nameuse{SF@\the\@tempcntb}\phantom{\braceld}$%
}%
\advance\@tempcntb \@ne
\Eunderbrace{\box0}\\
\repeat
\setbox0=\hbox{%
$\displaystyle\@nameuse{SF@\the\@tempcntb}\phantom{\braceld}$%
}%
\advance\@tempcntb \@ne
\ifsub
\Munderbrace{\box0}_{\splitsub}\\
\else
\Munderbrace{\box0}\\
\fi
\loop
\ifnum\@tempcntb<\count@
\setbox0=\hbox{%
$\displaystyle\@nameuse{SF@\the\@tempcntb}\phantom{\braceld}$%
}%
\advance\@tempcntb \@ne
\Eunderbrace{\box0}\\
\repeat
\setbox0=\hbox{%
$\displaystyle\@nameuse{SF@\the\@tempcntb}\phantom{\braceld}$%
}%
\Runderbrace{\box0}\\
\else
%nb line is even (two middles)
\advance\count@ \m@ne
\advance\@tempcnta \m@ne
% very left part
\setbox0=\hbox{$\displaystyle\@nameuse{SF@0}\phantom{\braceld}$}%
\Lunderbrace{\box0}\\
\@tempcntb=\@ne
% left parts
\loop
\ifnum\@tempcntb<\@tempcnta
\setbox0=\hbox{%
$\displaystyle\@nameuse{SF@\the\@tempcntb}\phantom{\braceld}$%
}%
\advance\@tempcntb \@ne
\Eunderbrace{\box0}\\
\repeat
\setbox0=\hbox{%
$\displaystyle\@nameuse{SF@\the\@tempcntb}\phantom{\braceld}$%
}%
\advance\@tempcntb \@ne
\setbox1=\hbox{%
$\displaystyle\@nameuse{SF@\the\@tempcntb}\phantom{\braceld}$%
}%
\advance\@tempcntb \@ne
\ifdim\wd0>\wd1
\ifsub
\Munderbrace{\box0}_{\splitsub}\\
\else
\Munderbrace{\box0}\\
\fi
\Eunderbrace{\box1}\\
\else
\Eunderbrace{\box0}\\
\ifsub
\Munderbrace{\box1}_{\splitsub}\\
\else
\Munderbrace{\box1}\\
\fi
\fi
\loop
\ifnum\@tempcntb<\count@
\setbox0=\hbox{%
$\displaystyle\@nameuse{SF@\the\@tempcntb}\phantom{\braceld}$%
}%
\advance\@tempcntb \@ne
\Eunderbrace{\box0}\\
\repeat
\setbox0=\hbox{%
$\displaystyle\@nameuse{SF@\the\@tempcntb}\phantom{\braceld}$%
}%
\Runderbrace{\box0}\\
\fi
\fi
}
\def\SU@countbs#1\\#2\@nil{%
\@namedef{SF@\the\count@}{$#1$}%
\def\SU@arg{#2}%
\advance\count@ \@ne
\ifx\empty\SU@arg
\let\next\@gobble
\else
\let\next\SU@countbs
\fi
\expandafter\next\SU@arg\@nil
}
\makeatother
\begin{document}
\parindent=0pt
$\splitunderbrace{a+b+c+d}_{xxx}$\par\bigskip
$\splitunderbrace{a+b+c+d+\\e+f+g+h}_{xxx}$\par\bigskip
$\splitunderbrace{a+b+c+d+\\e+f+g+h+\\i+j+k+l}_{xxx}$\par\bigskip
$\splitunderbrace{a+b+c+d+\\e+f+\\g+h+i+j+k+l+
\\m+n+o+p}_{xxx}$\par\bigskip
$\splitunderbrace{a+b+c+d+\\e+f+g+h+i+j+\\k+l+
\\m+n+o+p}_{xxx}$\par\bigskip
$\splitunderbrace{a+b+c+d+\\e+f+g+h+\\i+j+k+l+
\\m+n+o+p+\\q+r+s+t}_{xxx}$\par\bigskip
$\splitunderbrace{a+b+c+d+\\e+f+g+h+\\i+j+k+l+
\\m+n+o+p+\\q+r+s+t+\\u+v+w+x}_{xxx}$\par\bigskip
\end{document}