Monday, August 20, 2012

Aligning Matrix Columns in LaTeX

The standard amsmath packages provide a convenient interface to write matrices in LaTeX. For example, the following code produce the matrix:
$\begin{bmatrix} 1 & -1 \\ -1 & 1 \end{bmatrix}.$
Clearly the columns could do with some alignment. Of course, you could do it from scratch by using the array environment, but that would mean giving up the convenience of the AMS matrix environments.

Enter the mathtools package, which is an add-on to the amsmath packages. The mathtools package loads the amsmath packages, if they haven't already been.

Once you've loaded the mathtools package (using the usepackage command), you can specify the alignment of your matrices with a special starred environment as follows:
which yields:
Voila!