underbrace alignment fun & games
coo...@nospamverizon.net
underbraces in a multi-line equation array environment. I can achieve
'the right look' using brute force (trial and error with vertical
spacing elements in the math environment), but I'm hoping that someone
can point me to a more elegant solution. The following minimal example
shows an example of what I'm trying to do -- the first equation is 'what
it should look like', the second attempt is what it does look like
unless I embed a bunch of horizontal spacing controls. Basically, I'd
like the underbraces to be as wide as the element in the first line of
the equation, not the second (this will be clearer if you compile the
following...).
Thanks in advance...
\documentclass[11pt,letterpaper]{article}
\usepackage{amsmath}
\begin{document}
with `brute-force' horizontal spacing
\begin{align*}
\hat{S}_i &= \mu + \left(S_i-\mu\right) + \left(\hat{S}_i-S_i\right)\\
&=\mu+ \underbrace{\quad\;\delta_i\quad\;\,}_{\begin{smallmatrix}
\uparrow\;\sigma^2 \\
~\\
\text{\scriptsize{(process}}\\ \text{\scriptsize{variance)}}
\end{smallmatrix}} +
\,\underbrace{\quad\;\epsilon_i\quad\;\,}_{\begin{smallmatrix}
\uparrow\;\mbox{\scriptsize{var}}\left(\hat{S}_i|S_i\right) \\
~\\
\text{\scriptsize{(sampling}}\\ \text{\scriptsize{variance)}}
\end{smallmatrix}}
\end{align*}
without horizontal spacing
\begin{align*}
\hat{S}_i &= \mu + \left(S_i-\mu\right) + \left(\hat{S}_i-S_i\right)\\
&=\mu+ \underbrace{\delta_i}_{\begin{smallmatrix} \uparrow\;\sigma^2 \\
~\\
\text{\scriptsize{(process}}\\ \text{\scriptsize{variance)}}
\end{smallmatrix}} + \underbrace{\epsilon_i}_{\begin{smallmatrix}
\uparrow\;\mbox{\scriptsize{var}}\left(\hat{S}_i|S_i\right) \\
~\\
\text{\scriptsize{(sampling}}\\ \text{\scriptsize{variance)}}
\end{smallmatrix}}
\end{align*}
\end{document}
Enrico Gregorio
\usepackage{calc}
\newcommand{\centerto}[2]{%
\makebox[\widthof{$\displaystyle#2$}]{$\displaystyle#1$}}
...
\begin{align*}
\hat{S}_i &= \mu + (S_i-\mu) + (\hat{S}_i-S_i)\\
&=\mu +
\underbrace{\centerto{\delta_i}{(S_i-\mu)}}
_{\begin{subarray}{c}
\uparrow\;\sigma^2\\
\text{(process}\\
\text{variance)}
\end{subarray}}
+
\underbrace{\centerto{\epsilon_i}{(\hat{S}_i-S_i)}}
_{\begin{subarray}{c}
\uparrow\;\operatorname{var}(\hat{S}_i\mid S_i)\\
\text{(sampling}\\
\text{variance)}\\
\end{subarray}}
\end{align*}
Ciao
Enrico
GL
You can also consider using \substrack, with \\[dimen] for spacing:
\begin{align*}
\hat S_i &= \mu + \left(S_i-\mu\right) + \left(\hat S_i-S_i\right)\\
&= \mu + \underbrace{\quad\;\delta_i\quad\;\,}_{\substack
{\uparrow\;\sigma2 \\[1ex]
\text{(process}\\ \text{variance)}}}
+
\,\underbrace{\quad\;\epsilon_i\quad\;\,}_{\substack{\uparrow\;\operatorname{var}\left(\hat
S_i\middle| S_i\right) \\
\text{{(sampling}}\\ \text{{variance)}}}}
\end{align*}
coo...@nospamverizon.net
> <coo...@NOSPAMverizon.net> wrote:
>
>> Trying to figure out an 'elegant' way to control location/spacing of
>> underbraces in a multi-line equation array environment. I can achieve
>> 'the right look' using brute force (trial and error with vertical
>> spacing elements in the math environment), but I'm hoping that someone
>> can point me to a more elegant solution. The following minimal example
>> shows an example of what I'm trying to do -- the first equation is 'what
>> it should look like', the second attempt is what it does look like
>> unless I embed a bunch of horizontal spacing controls. Basically, I'd
>> like the underbraces to be as wide as the element in the first line of
>> the equation, not the second (this will be clearer if you compile the
>> following...).
>>
>> Thanks in advance...
>>
>> \documentclass[11pt,letterpaper]{article}
>>
>> \usepackage{amsmath}
>>
>> \begin{document}
>>
>> with `brute-force' horizontal spacing
>>
>> \begin{align*}
>> &=\mu+ \underbrace{\quad\;\delta_i\quad\;\,}_{\begin{smallmatrix}
>> \uparrow\;\sigma^2 \\
>> ~\\
>> \text{\scriptsize{(process}}\\ \text{\scriptsize{variance)}}
>> \end{smallmatrix}} +
>> \,\underbrace{\quad\;\epsilon_i\quad\;\,}_{\begin{smallmatrix}
>> \uparrow\;\mbox{\scriptsize{var}}\left(\hat{S}_i|S_i\right) \\
>> ~\\
>> \text{\scriptsize{(sampling}}\\ \text{\scriptsize{variance)}}
>> \end{smallmatrix}}
>> \end{align*}
>>
>> without horizontal spacing
>>
>> \begin{align*}
>> &=\mu+ \underbrace{\delta_i}_{\begin{smallmatrix} \uparrow\;\sigma^2 \\
>> ~\\
>> \text{\scriptsize{(process}}\\ \text{\scriptsize{variance)}}
>> \end{smallmatrix}} + \underbrace{\epsilon_i}_{\begin{smallmatrix}
>> \uparrow\;\mbox{\scriptsize{var}}\left(\hat{S}_i|S_i\right) \\
>> ~\\
>> \text{\scriptsize{(sampling}}\\ \text{\scriptsize{variance)}}
>> \end{smallmatrix}}
>> \end{align*}
>>
>> \end{document}
>
> \usepackage{calc}
> \newcommand{\centerto}[2]{%
> \makebox[\widthof{$\displaystyle#2$}]{$\displaystyle#1$}}
>
>
> ...
>
> \begin{align*}
> &=\mu +
> \underbrace{\centerto{\delta_i}{(S_i-\mu)}}
> _{\begin{subarray}{c}
> \uparrow\;\sigma^2\\
> \text{(process}\\
> \text{variance)}
> \end{subarray}}
> +
> \underbrace{\centerto{\epsilon_i}{(\hat{S}_i-S_i)}}
> _{\begin{subarray}{c}
> \uparrow\;\operatorname{var}(\hat{S}_i\mid S_i)\\
> \text{(sampling}\\
> \text{variance)}\\
> \end{subarray}}
> \end{align*}
>
> Ciao
> Enrico
Very slick -- works very well. Thank you very much!
coo...@nospamverizon.net
Hmm -- looks intriguing, but I can't get it to compile.
Enrico Gregorio
I let TeX do the measurements; with \centerto I tell it
to place the first argument in a space as wide as the
second.
For multiple line subscripts, there's "subarray", to
which you can tell the alignment.
Ciao
Enrico
Joris Pinkse
> <coo...@NOSPAMverizon.net> wrote:
>
>> Very slick -- works very well. Thank you very much!
>
> I let TeX do the measurements; with \centerto I tell it
> to place the first argument in a space as wide as the
> second.
>
> For multiple line subscripts, there's "subarray", to
> which you can tell the alignment.
>
> Ciao
> Enrico
Presumably you can achieve much the same thing with \hphantom.
GL
> On 7/6/2011 3:06 PM, GL wrote:
>>
>>
>> You can also consider using \substrack, with \\[dimen] for spacing:
>>
\documentclass [a4paper]{article}
\usepackage {amsmath}
\begin{document}
\begin{align*}
\hat S_i &= \mu + \left(S_i-\mu\right) + \left(\hat S_i-S_i\right)\\
&= \mu + \underbrace{\quad\;\delta_i\quad\;\,}
_{\substack {\uparrow\;\sigma2 \\[1ex]
\text{(process}\\ \text{variance)}}}
+ \,\underbrace{\quad\;\epsilon_i\quad\;\,}
_{\substack{\uparrow\;\operatorname{var}
\left(\hat S_i\middle| S_i\right) \\
\text{{(sampling}}\\ \text{{variance)}}}}
\end{align*}
\end{document}\endinput
> Hmm -- looks intriguing, but I can't get it to compile.
This is because those crap environment from the AmS don't allow
a blank line in their body...
Regards.
Enrico Gregorio
The problem is not only to leave a space, but to place an
object in the middle of it. There are other solutions, of course,
for example
\newcommand{\centerto}[2]{%
{\ooalign{$\displaystyle\hphantom{#2}$\cr
\hidewidth$\displaystyle#1$\hidewidth\cr}}}
which does not require calc, but requires to know \ooalign.
In any case TeX has to typeset #2 in order to measure its
width.
Ciao
Enrico
GL
Yes and what if you want to extend the mechanism to typeset :
A = ÔøΩ + .... + ..... \\
= ÔøΩ + ..... + ..... \\
= ÔøΩ + ...... + ...... \\
= ÔøΩ + ... + ... \\
|------| |------|
Is there something to align the operands ? {array} ?
Regards.
Lars Madsen
alignat, though it may cost a few extra &'s and perhaps a few {}'s
Enrico Gregorio
I'd set an \halign with a dummy last row; then I'd get at
\lastbox, dismantle it and use the measures for setting
the lengths of the braces.
Too complicated: some visual formatting is sometimes the
fastest way. Such constructions are not so frequent as
to require a general solution.
Ciao
Enrico
GL
Alignment requires & obviously... Then AmS can give the columns widths:
\documentclass [a4paper]{article}
\usepackage {amsmath}
\begin{document}\makeatletter
\def\AmScolumnwidth #1{\ifmeasuring@ #1\else
\hbox to\AmScolumn@width {\hss$#1$\hss}\fi }
\def\AmScolumn@width {\ifcase \numexpr\column@+1\maxcolumn@widths \fi }
\begin{alignat*}{6}
\hat S_i &= \mu &+ &\left(S_i-\mu\right) &+& \left(\hat S_i-S_i\right)\\
&= \mu &+ &\underbrace{\AmScolumnwidth{\delta_i}}
_{\substack {\uparrow\;\sigma2 \\[1ex]
\text{(process}\\ \the\column@
\text{variance)}}}
&+ &\underbrace{\AmScolumnwidth{\epsilon_i}}
_{\substack{\uparrow\;\operatorname{var}
\left(\hat S_i\middle| S_i\right) \\
\text{{(sampling}}\\
\text{{variance)}}}}
\end{alignat*}
\end{document}\endinput
\substack for concision but subarray would go as well.
Cheers.
GL
Not too complicated if one know how AmS stores its dimensions.
But too late, i've posted the solution already... might be of interest
for something else yet.
>
> Ciao
> Enrico