# Help with Matrix in Latex

Hi,

I am trying to produce a matrix in Latex with the following code:
Code:
\begin{bmatrix}
1 & 0 & 0 & 0 & 0 & 0 & 0 & -4 & 1 & 0 & 0 & 0 & 0 & 0 \\
0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 & 0 & 0 \\
0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 & 0 \\
0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 \\
0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 \\
0 & 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 \\
0 & 0 & 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4
\end{bmatrix}
But I keep on getting the following error:
Extra alignment tab has been changed to \cr.<recently read> \endtemplate

This error occurs for each row in that matrix.

I would appreciate any help anyone can give,

Thanks,

Ryan

## Answers and Replies

I create matrices like this

Code:
$$\left[ \begin{array}{ccc} 1 & 0 & 0\\ 0 & 1 & 0\\ 0 & 0 & 1 \end{array} \right]$$

HallsofIvy
Science Advisor
Homework Helper
I just copied your code into tex and it gives

$$\begin{bmatrix} 1 & 0 & 0 & 0 & 0 & 0 & 0 & -4 & 1 & 0 & 0 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 & 0 & 0 \\ 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 & 0 \\ 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 \\ 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 \\ 0 & 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 \\ 0 & 0 & 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 \end{bmatrix}$$
Is there a maximum of 10 columns in a matrix?

If we try to do it "by hand" (using \begin{array})
$$\left[\begin{array}{cccccccccccccc} 1 & 0 & 0 & 0 & 0 & 0 & 0 & -4 & 1 & 0 & 0 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 & 0 & 0 \\ 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 & 0 \\ 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 \\ 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 \\ 0 & 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 \\ 0 & 0 & 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 \end{array}\right]$$

The code for that is
\left[\begin{array}{cccccccccccccc}
1 & 0 & 0 & 0 & 0 & 0 & 0 & -4 & 1 & 0 & 0 & 0 & 0 & 0 \\
0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 & 0 & 0 \\
0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 & 0 \\
0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 & 0 \\
0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 & 0 \\
0 & 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4 & 1 \\
0 & 0 & 0 & 0 & 0 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 1 & -4
\end{array}\right]

Notice that, using \begin{array}, you need to put in the braces (\left[ and \right]) yourself (so you could use ( ), { }, etc.). The {cccccccccccccc} (14 c's) tells LaTex there are 14 columns.

Last edited by a moderator:
Thanks, that worked great.

Ryan

statdad
Homework Helper
(I believe) There is a default for the maximum number of columns in the matrix environments, and that it is possible to change it in your document.

I don't have the pertinent information at my fingertips now; perhaps a search of tug.org
or some other site would be fruitful.
Edit: spoke too soon: from AMS math documentation, footnote on page 10.

More precisely: The maximum number of columns in a matrix is determined by the
counter MaxMatrixCols (normal value = 10), which you can change if necessary using LATEX’s
\setcounter or \addtocounter commands.

Thanks statdad.

Is there any advantage of using \begin{bmatrix} over \left[\begin{array}?

Ryan

statdad
Homework Helper
Thanks statdad.

Is there any advantage of using \begin{bmatrix} over \left[\begin{array}?

Ryan

That I can't say, as I use the "bmatrix" environment exclusively. As some other posters have shown, it is possible to control column alignment in arrays; I don't know of a similar feature with the matrix environments.

Ok thanks