alignequationslyxnumbering
I would like to create automatic numbering of equations in LyX. when I entered
\renewcommand\[{\begin{equation}}
\renewcommand\]{\end{equation}}
for the "equation" environment it worked. However, when trying to make the align* environment numbering
\renewcommand{\begin{align*}}{\begin{align}}
\renewcommand{\end{align*}}{\end{align}}
it produces errors, such as "LaTeX Error: \begin{align*}undefined".
how can I overcome this?
I'm not sure why but you can't use \begin{align} and \end{align} in the definition of a new environment; you have to use the "lower-level" macros \align and \endalign instead. Edit: as pointed by alexwlchan in his comment, you can find more details about that in section 6 of Technical notes on the amsmath package.
Here I've used the equivalent of an align* environment (see Herbert's answer to Define a custom align, and align* environment).
Note that you will get an error if you try to reset your grammarcounter at each chapter in the article class, because the latter doesn't have chapters; \section is the most high-level sectioning command in the article class. Did you mean
\numberwithin{grammarcounter}{section}
instead?
\documentclass{article}
\usepackage{amsmath}
\newcounter{grammarcounter}[section]
\makeatletter
\newenvironment{grammar}
{%
\refstepcounter{grammarcounter}
\start@align\@ne\st@rredtrue\m@ne
\tag{$\Gamma_{\thegrammarcounter}$}
}{%
\endalign
}
\makeatother
\begin{document}
\section{Foo}
\begin{grammar}
\label{gr:label}
E &::= E + E \\
E &::= a \\
E &::= b
\end{grammar}
\begin{grammar}
\label{gr:label2}
E &::= E + E \\
E &::= a \\
E &::= b
\end{grammar}
\end{document}
Update
Since the release of LaTeX from 2018/04/01 the mentioned package chngcntr is now part of the LaTeX kernel -- it's not necessary to load it separately.
Using \numberwithin{equation}{subsection} changes the counter output format and shifts the resetting of the equation counter from section to subsection level (i.e. each time \stepcounter{subsection} is used. However, this means that an orphane equation after a \section, but before \subsection will just use the old counter value, from a previous equation.
This resets the counter of equation number each time a new \section is used, but will not change the \theequation command (being the counter formatting macro)
\makeatletter
\@addtoreset{equation}{section}
\makeatother
As an alternative to this low-level variant, it's possible to use
\usepackage{chngcntr}
\counterwithin{equation}{section}
in the preamble.
However, this will not solve the issue with trailing 0 if the subsection number is 0. This can be attacked with a conditional within \theequation or -- the better way -- avoid equations outside of \subsection if subsection is the driver counter.
\documentclass[12pt]{article}
\usepackage{amsmath}
\makeatletter
\@addtoreset{equation}{section}
\makeatother
\numberwithin{equation}{subsection}
\begin{document}
\section{1}
\begin{equation}
1
\end{equation}
\subsection{1}
\begin{equation}
1
\end{equation}
\subsection{1}
\begin{equation}
1
\end{equation}
\begin{equation}
1
\end{equation}
\section{1}
\begin{equation}
1
\end{equation}
\subsection{1}
\begin{equation}
1
\end{equation}
\section{1}
\begin{equation}
1
\end{equation}
\subsection{1}
\begin{equation}
1
\end{equation}
\end{document}
Best Answer
As LyX normally loads
amsmathautomatically if you use one of its environments, I just had to redefine the environment, by adding the following to the preamble:Example of result, having added a simple
alignenvironment from the LyX menus:I used the "command forms"
\alignand\endalignas I think I read somewhere on this site that those are recommended in definitions of environments. Please comment if I'm wrong.If you still get the error message, try loading
amsmathexplicitly, by either\usepackage{amsmath}the Document --> Settings --> LaTeX preamble, orA better option, in my opinion
Instead of redefining
align*toalign, you can add a keyboard shortcut to add a numberedalign. This is done in Tools --> Preferences --> Editing --> Shortcuts (see my answer on Shortcuts for Lemma, Claim, Theorem etc for some more detail, should that be needed). Add a new shortcut, and typeas the function. You could for example use Ctrl+Alt+Shift+A as the shortcut, in which case the dialog would look as follows:
Having done this, just hit the specified shortcut, and you have a numbered
alignenvironment.Similarly you can create a keyboard shortcut for a numbered equation. Just replace
alignwithequationin the function above, making itCtrl+Alt+Shift+M is free (unless you've defined it yourself), so then only the Alt is the difference between a numbered and an unnumbered. You could of course change these around, making Ctrl+Shift+M create a numbered equation.