# Effortlessly Create a Matrix in Latex: Step-by-Step Guide

• LaTeX
• ryan88
In summary, the conversation discusses producing a matrix in LaTeX using the code for \begin{bmatrix} and \left[\begin{array}. The conversation also addresses an error that occurs when creating the matrix and options for changing the maximum number of columns in a matrix. The conversation concludes with a discussion on the advantages of using \begin{bmatrix} over \left[\begin{array}.
ryan88
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

I create matrices like this

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

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

(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

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

Ryan

ryan88 said:

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

## 1. How do I create a matrix in Latex?

To create a matrix in Latex, you can use the "bmatrix" environment or the "array" environment. The "bmatrix" environment is recommended for simpler matrices, while the "array" environment allows for more customization.

## 2. How do I add elements and format my matrix in Latex?

To add elements to your matrix, use the "&" symbol to separate columns and "\\" to separate rows. You can use commands such as "\pmatrix" for parentheses or "\begin{vmatrix}" for vertical bars to format your matrix. Additionally, you can use commands like "\hline" to add horizontal lines for clarity.

## 3. How do I align my matrix in Latex?

To align your matrix, you can use the "align" environment. Within this environment, you can use the "&" symbol to indicate where to align the columns. For example, "&=" will align the columns at the equal sign. You can also use the "center" environment for centered alignment.

## 4. How do I label and reference my matrix in Latex?

To label your matrix, use the "\label" command after the "\begin{bmatrix}" or "\begin{array}" command. Then, to reference the matrix in your text, use the "\ref" command followed by the label name. This will automatically generate the correct number for your matrix.

## 5. How do I insert a matrix in an equation in Latex?

To insert a matrix within an equation, use the "array" environment within the "$$" and "$$" commands. You can then use the "&" symbol to indicate where to align the columns, just like in the "align" environment. This will allow you to insert a matrix as part of a larger equation.

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