I can represent an upper trapezoidal matrix say as shown below. I would like to replace all those zeros with a single big zero that spans across the low triangle rows and columns, and maybe also add a delimiter along the diagonal that clearly shows it is an upper diagonal matrix. How can I do that?
\newcommand\x{\XSolid}
%\newcommand\x{\ding{53}}
\begin{equation}
\left(
\begin{array}{*5{c}}
\x & \x & \x & \x & \x \\
0 & \x & \x & \x & \x \\
0 & 0 & \x & \x & \x \\
0 & 0 & 0 & \x & \x \\
0 & 0 & 0 & 0 & \x \\
\end{array}\right)
\end{equation}
Separate question ... why the \x
command I define outputs #
rather than the intended cross symbol? It outputs the same symbol #
no matter if I use \XSolid
or \ding{53}
UPDATE: taking the answer as input, I ended doing this:
\newcommand\x{\times}
\newcommand\bigzero{\makebox(0,0){\text{\huge0}}}
\newcommand*{\bord}{\multicolumn{1}{c|}{}}
\begin{equation}
\left(
\begin{array}{ccccc}
\x & \x & \x & \x & \x \\ \cline{1-1}
\bord & \x & \x & \x & \x \\ \cline{2-2}
& \bord & \x & \x & \x \\ \cline{3-3}
& \bigzero & \bord & \x & \x \\ \cline{4-4}
& & & \bord & \x \\ \cline{5-5}
\end{array}\right)
\end{equation}
which produces this:
\documentclass{article}\begin{document}\XSolid\end{document}
results in! Undefined control sequence.
, thus I assume you are loading a package to define\XSolid
? Which package/which version, please? – Stephen Aug 30 '12 at 15:17\XSolid
has been defined somewhere but I have no idea where exactly. Oh I think the package that defines\XSolid
is TikZ – SkyWalker Aug 30 '12 at 15:22\show\XSolid
in the preamble. When it is still undefined, it will print to the log "> \XSolid=undefined. ", when it is defined it will give the definition, and if the definition is changed (from X to #), it will give a changed definition. For a lot of packages this might be a lot of work to find which package (re-)defines it... – Stephen Aug 30 '12 at 15:29