Math & Science ⇒ Equation not centered

[Cham]

Is there a way to "smash" the tag number ?

[Stefan Kottwitz]

Most can be redefined and patched, also tagging macros. Just be aware, that redefining internal macros can mean that it doesn't work with future packages releases which decide to change internal macros. Well, it would work now. So, one way of horizontal smashing is using \makebox with a value of 0pt. With 0pt we get a line break though, but let's choose the smallest TeX unit and it works. Just insert right before your \makeatother:

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\renewcommand*{\maketag@@@}[1]{\hbox{\m@th\normalfont{\makebox[1sp][r]{#1}}}}

Stefan

[Cham]

Thanks Stefan, this works.

Unfortunately, it may cause problems with lots of other equations (I didn't checked yet).

Is there a way to achieve the same effect on a particular equation, without affecting the others ?

[Cham]

OUCH !

Stefan, your modification affects all the equation references in the text. Just add a \label{} to an equation and use \eqref{} in the text, and it will be messed-up !

[cgnieder]

How about this: use mathtools instead of amsmath (the first loads the latter anyway) and define a tagform nospace:

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\newtagform{nospace}[\llap\bgroup(]{}{\egroup)}

I could imagine that this works for all tags but even if it doesn't you could switch back and forth with \usetagform.

Here is a complete example (also note that I change the equation counter with amsmath's \numberwithin):

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\documentclass{book}
\usepackage{mathtools}
\usepackage{tensor}

\newtagform{nospace}[\llap\bgroup(]{}{\egroup)}

\numberwithin{equation}{section}

\usepackage[nopar]{lipsum}% for dummy text
\begin{document}
\chapter{Blah}
\section{Blub}
\lipsum[4]
\usetagform{nospace}
\begin{equation}
  \frac{d^2 \, \displaystyle{\tensor{x}{^{\lambda}}}}{d\, \sigma^2} +
  \Gamma_{\mu \nu}^{\lambda} \; \frac{d\, \displaystyle{\tensor{x}{^{\mu}}}}{d\, \sigma} \,
  \frac{d\, \displaystyle{\tensor{x}{^{\nu}}}}{d\, \sigma} =
  \frac{d\, \displaystyle{\tensor{x}{^{\lambda}}}}{d\, \sigma} \,
  \frac{d\, }{d\, \sigma} \, \ln \sqrt{\, \tensor{g}{_{\mu \nu}} \;
  \frac{d\, \displaystyle{\tensor{x}{^{\mu}}}}{d\, \sigma} \,
  \frac{d\, \displaystyle{\tensor{x}{^{\nu}}}}{d\, \sigma}}.
\end{equation}
\usetagform{default}
\lipsum[4]
\begin{equation}
  \tensor{g}{_{\mu \nu}} \; \frac{d\, \displaystyle{\tensor{x}{^{\mu}}}}{d\, \sigma} \,
  \frac{d\, \displaystyle{\tensor{x}{^{\nu}}}}{d\, \sigma} =
  \tensor{g}{_{\mu \nu}} \; \frac{d\, \displaystyle{\tensor{x}{^{\mu}}}}{d\, \tau} \,
  \frac{d\, \displaystyle{\tensor{x}{^{\nu}}}}{d\, \tau} \,
  \Big( \, \frac{d\, \tau}{d\, \sigma} \Big)^{\! 2} \equiv
  \Big( \, \frac{d\, \tau}{d\, \sigma} \Big)^{\! 2}.
\end{equation}
\lipsum[4]
\end{document}

Regards

[cgnieder]

Note: this will also affect a possible reference to the equation.

[Cham]

Thanks cgnieder, your solution appears to work very well.

Since I'm already using the mathtools package in my real document, I may simply add this code to the preamble :

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\newtagform{nospace}[\llap\bgroup(]{}{\egroup)}

just under my usual tag modification :

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\makeatletter
\renewcommand\theequation{\thesection.\arabic{equation}}
\@addtoreset{equation}{section}
\makeatother

Then using \usetagform{nospace} and \usetagform{default} around a special equation solves the issue for that particular equation. All other equations are left untouched.

[cgnieder]

just under my usual tag modification :

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\makeatletter
\renewcommand\theequation{\thesection.\arabic{equation}}
\@addtoreset{equation}{section}
\makeatother

You can replace this with

Code: Select all

\numberwithin{equation}{section}

It has the same effect.

Regards

[Cham]

You can replace this with

Code: Select all

\numberwithin{equation}{section}

It has the same effect.

Hmmm, yes. But I must admit that I'm pretty nervous about modifying my preamble, because my document is now so large and complex, I don't want to mess with this huge castle of cards.

Changing just a single line of code in the preamble may have HUGE consequences on the whole document.

[Cham]

Since I'm no expert in LaTeX coding : Before adopting cgnieder's solution, I would like to hear comments from the other "pros" here about his solution.

Is there any inconvenience about that solution ?

Apparently, it's working very well in my document (but I didn't checked all of the 700 pages yet!), and as I said in my previous message, I'm more and more reluctant to modify my preamble (it's now a huge "castle of cards").