# Eikonal Blog

## 2010.07.13

Filed under: TeX — Tags: , , , , , , , , , , — sandokan65 @ 16:03

## (to be a) Cheatsheet

### Lists

 \begin{list}{label code}{body code} \item Item one \item Item two \item Item three \end{list} 

Example:

 \begin{list}{*}{} \item Item one \item Item two \item Item three \end{list} 

### Error: “extra alignment tab has been changed to \cr” in pmatrix environment

Trying to compile the matrix with 16 columns:

 $$\begin{pmatrix} 1&0&0&0& 0&0&0&0& 0&1&0&0& 0&0&0&0 \\ 0&0&0&0& 1&0&0&0& 0&0&0&0& 0&1&0&0 \\ 0&0&1&0& 0&0&0&0& 0&0&0&1& 0&0&0&0 \\ 0&0&0&0& 0&0&1&0& 0&0&0&0& 0&0&0&1 \end{pmatrix}$$ 

produced following error:

 ./document.tex:750: Extra alignment tab has been changed to \cr. \endtemplate l.750 1&0&0&0& 0&0&0&0& 0&1& 0&0& 0&0&0&0 \\ 

It appears that LaTeX has some internal limitation on default maximal number of columns. This can be changed (accoring to http://newsgroups.derkeiler.com/Archive/Comp/comp.text.tex/2006-06/msg01298.html) by setting

 \setcounter{MaxMatrixCols}{16} 

in the preamble of the document.