# longtabu, column width

having an issue with longtabu and setting columns to a percentage of the table width. I've achieved what i want with tabularx:

\documentclass{report}

\usepackage{tabularx}
\begin{document}

\begin{tabularx}{\textwidth}{
>{\hsize=.1\hsize}X
>{\hsize=.1\hsize}X
>{\hsize=.1\hsize}X
>{\hsize=.7\hsize}X} % 70% of table width
\hline
\textbf{Time End of Step} &
\textbf{Step} &
\textbf{Event} &
\textbf{Description}
\\ \hline
12:18:52 & 1 & 1 & this is a description for the event \\
12:18:52 & 1 & 1 & this is a description for the event \\
12:18:52 & 1 & 1 & this is a description for the event \\
\end{tabularx}

\end{document}


then i try with tabu:

\documentclass{report}

\usepackage{longtable,tabu}
\begin{document}

\begin{longtabu} to \textwidth {
>{\hsize=.1\hsize}X
>{\hsize=.1\hsize}X
>{\hsize=.1\hsize}X
>{\hsize=.7\hsize}X} % 70% of table width
\hline \hline
\textbf{Time End of Step} &
\textbf{Step} &
\textbf{Event} &
\textbf{Description}
\\ \hline \hline \hline \hline
12:18:52 & 1 & 1 & this is a description for the event \\
12:18:52 & 1 & 1 & this is a description for the event \\
12:18:52 & 1 & 1 & this is a description for the event \\
\end{longtabu}

\end{document}


So this produces an error, saying dimension too large. Anyone know how to use this hsize in longtabu? Thanks!

docs for http://mirror.unl.edu/ctan/macros/latex/contrib/tabu/tabu.pdf are found here. after reviewing them. ive come up with a solution.

\documentclass{report}

\usepackage{longtable,tabu}
\begin{document}

\begin{longtabu} to \textwidth {
X[1,c]
X[1,c]
X[1,c]
X[10,l]}
\hline \hline
\textbf{Time End of Step} &
\textbf{Step} &
\textbf{Event} &
\textbf{Description}
\\ \hline \hline \hline \hline
12:18:52 & 1 & 1 & this is a description for the event \\
12:18:52 & 1 & 1 & this is a description for the event \\
12:18:52 & 1 & 1 & this is a description for the event \\
\end{longtabu}

\end{document}


So this is not exactly percentages but it will be good enough for what im working on. X[1,c] means its coefficient is 1 and its alignment is center. So in my above the coefficients add up to 13. so the first column will be 1/13 (7.6%) of the total table width. where as the last column will be 10/13 (76%).