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Asked: 2020-10-01 09:57:06 +0800 CST 2020-10-01 09:57:06 +0800 CST

Align relative to a sign/symbol/character in LaTex?

  • 772

I have the following code to make an array in LaTex:

\begin{eqnarray*}
        \Hess f(\bar{x}) & = &
        \left( \begin{array}{ccc}
        \partial f_{11} & \partial f_{12} & \partial f_{13} \\ 
        \partial f_{21} & \partial f_{22} & \partial f_{23} \\ 
        \partial f_{31} & \partial f_{32} & \partial f_{33}
        \end{array} \right)\\ & = &
        \left( \begin{array}{cccc}
        0 & 1 & 0\\
        1 & 0 & 1\\
        0 & 1 & 0
        \end{array} \right)     
\end{eqnarray*}

Which shows this:

enter image description here

However, that is not what I want and it is not what it should show, according to the reference that I used (and that I also tried) the code should generate what it showed above but with the arrays aligned by the equals symbol '=' as I indicated with the '&'.
I also tried \begin{align*} which should give the same result (with simple equations, that is, without matrices, I get the alignment).
So, I don't know if what I'm doing is wrong or not allowed, in any case I need help to do that if it can be done.

latex

1 Answers

  1. Best Answer

    Its syntax works (be careful with the header), as much eqnarray*as align*it should work as shown below.

    But align*it is much preferable to eqnarray*( source ), this is very important!!

    The second array is {ccc}, no {cccc}!

    I'm sorry but I only speak Italian and I used Google translate :)

    \documentclass{article}
\usepackage{amsmath}

\newcommand{\Hess}{\mathcal{H}}

\begin{document}

\begin{eqnarray*}
  \Hess_f(\bar{x}) & = &
  \left( \begin{array}{ccc}
    \partial f_{11} & \partial f_{12} & \partial f_{13} \\ 
    \partial f_{21} & \partial f_{22} & \partial f_{23} \\ 
    \partial f_{31} & \partial f_{32} & \partial f_{33}
  \end{array} \right)\\ & = &
  \left( \begin{array}{ccc}
    0 & 1 & 0\\
    1 & 0 & 1\\
    0 & 1 & 0
  \end{array} \right)     
\end{eqnarray*}

\begin{align*}
  \Hess_f(\bar{x}) & = %
  \left( \begin{array}{ccc}
    \partial f_{11} & \partial f_{12} & \partial f_{13} \\ 
    \partial f_{21} & \partial f_{22} & \partial f_{23} \\ 
    \partial f_{31} & \partial f_{32} & \partial f_{33}
  \end{array} \right)\\ & = %
  \left( \begin{array}{ccc}
    0 & 1 & 0\\
    1 & 0 & 1\\
    0 & 1 & 0
  \end{array} \right)     
\end{align*}

\end{document}

    screenshot of output

    • 1