# Matrix equation and \notag

My problem is related to the following "equation":

\begin{align}
\left(
\begin{matrix}
\shat{X} \notag \\
\shat{X}' \notag \\
\shat{Y} \notag \\
\shat{Y}' \\
\end{matrix}
\right)_{n+1}
= R(\omega_x, \omega_y)
\left(
\begin{matrix}
\shat{X}  \\
\shat{X}' + \shat{X}^2 - \chi \shat{Y}^2 + \kappa \left( \shat{X}^3 - 3 \chi \shat{X} \shat{Y}^2 \right)  \\
\shat{Y}  \\
\shat{Y}' - 2 \chi \shat{X} \shat{Y} - \kappa \left( \chi^2 \shat{Y}^3     - 3 \chi \shat{X}^2 \shat{Y} \right)  \\
\end{matrix}
\right)_n
\end{align}


It looks like I have to use notag for each line to avoid the individual line/equation numbering. Why is that ?

The next problem is: when I use 'notag' for each line, then the result is completely ugly, and the delimiters are in the wrong order (something strange with ) before ( ...

I'm using memoir with amsmath.

EDIT:

The shat command is defined as

\newcommand{\shat}[1]{\ensuremath{\hat{#1}}}


and it seems to work.

The problem looks the same for this simpler case:

-
Where does the \shat command comes from? – Gonzalo Medina Apr 11 '11 at 13:25
@Gonzalo : I edited the question. – Cedric H. Apr 11 '11 at 13:32
Two side comments: (a) why not use pmatrix instead of \left( \begin{matrix}...\end{matrix}\right)? (b) there's no need to include the line break \\ after the last row of the matrix entries. – Willie Wong Apr 11 '11 at 13:37
(after the update) I cannot reproduce. Wrapping your code inside \documentclass{memoir} \usepackage{amsmath}, with the definition of \shat in the preamble, and with the \notag removed, compiles just fine. Can you include a full minimum example (including preamble etc.)? – Willie Wong Apr 11 '11 at 13:42
@Willie: I found the problem: incompatibility between memoir and tabls. – Cedric H. Apr 21 '11 at 15:12

Cannot reprocude the problem, please post a full minimal example. This (using pmatrix works fine)

\documentclass[a4paper]{memoir}
\usepackage{amsmath}
\newcommand{\shat}[1]{\ensuremath{\hat{#1}}}
\begin{document}
\begin{align}
\begin{pmatrix}
\shat{X}  \\
\shat{X}' \\
\shat{Y}  \\
\shat{Y}' \\
\end{pmatrix}_{n+1}
= R(\omega_x, \omega_y)
\begin{pmatrix}
\shat{X}  \\
\shat{X}' + \shat{X}^2 - \chi \shat{Y}^2 + \kappa \left( \shat{X}^3
- 3 \chi \shat{X} \shat{Y}^2 \right)  \\
\shat{Y}  \\
\shat{Y}' - 2 \chi \shat{X} \shat{Y} - \kappa \left( \chi^2
\shat{Y}^3     - 3 \chi \shat{X}^2 \shat{Y} \right)  \\
\end{pmatrix}_n
\notag
\end{align}
\end{document}

-
With your example I obtain what I want, if I remove the notag... and I was about to post an example of my code almost similar ... except for other packages I load. In my case every line of the matrices are numbered... – Cedric H. Apr 12 '11 at 8:54
@Cedric: so one of the other packages is causing problems. Try commenting out all packages in your preamble and uncommenting them one by one, and see which one causes the error. If you can't find it, you should probably post your full example by editing the question text. – Willie Wong Apr 12 '11 at 11:10
@Willie: thanks, apparently it was a problem with tabls. – Cedric H. Apr 21 '11 at 15:14