6

How do I create a Toeplitz matrix like the following in LaTeX?

matrix

11
\documentclass{article}
\usepackage{mathtools}
\begin{document}

\[ %\arraycolsep=4pt
 G = 
 \begin{bmatrix*}[r]
    1 \\
    2&1\\
   -1&2&1\\
     &-1&2&1\\
     &&-1&2&1\\
     &&&-1&2&1\\
     &&&&&&\ddots\\
     &&&&&&&\ddots\\
     &&&&&&&&\ddots\\
     &&&&&&&&&1
  \end{bmatrix*}
\]
\end{document}

enter image description here

  • 1
    I think the last row must contain all non-zero elements: -1 2 1 – Robert Fuster Apr 28 '14 at 9:00
8

Here you go:

\documentclass{article}
\pagestyle{empty}% for cropping
\usepackage{amsmath}
\begin{document}
\begin{equation*}
  G =
  \begin{bmatrix}
    1 \cr
    2&1\cr
    -1&2&1\cr
    &-1&2&1\cr
    &&-1&2&1\cr
    &&&-1&2&1\cr
    &&&&&&\ddots\cr
    &&&&&&&\ddots\cr
    &&&&&&&&\ddots\cr
    &&&&&&&&&1\cr
  \end{bmatrix}
\end{equation*}
\end{document}

enter image description here

To get nicer alignment of the minus-signs you could use an array with right-aligned columns

\documentclass{article}
\pagestyle{empty}% for cropping
\usepackage{amsmath}
\begin{document}
\begin{equation*}
  G =
  \left[
    \begin{array}{*{10}r}
      1 \cr
      2&1\cr
      -1&2&1\cr
      &-1&2&1\cr
      &&-1&2&1\cr
      &&&-1&2&1\cr
      &&&&&&\ddots\cr
      &&&&&&&\ddots\cr
      &&&&&&&&\ddots\cr
      &&&&&&&&&1\cr
    \end{array}
  \right]
\end{equation*}
\end{document}

enter image description here

  • 3
    to get the right alignment, it's simpler to load the mathtools package and write: begin{bmatrix*}[r] … \end{bmatrix*}. – Bernard Apr 28 '14 at 8:36
  • Is there a reason to use \cr instead of `\`? – Manuel Apr 28 '14 at 14:53
  • 1
    @Manuel Because I often use plain TeX and there is no \\. In this case both are equivalent. Also \cr is primitive, hence it doesn't need to get expanded, you may save half a nano-second by that. – Henri Menke Apr 28 '14 at 15:06
2

Although late to the race my entry is presented below:

\documentclass[12pt]{article}
\usepackage{mathtools}
\usepackage{amssymb}

\begin {document}
\begin{equation}
\begin{pmatrix}
2 & -1 & 0 & \cdots & \cdots & \cdots & \cdots & 0\\
-1 & 2 & -1 & 0 & & & & \vdots\\
0 & -1 & 2 & -1 & \ddots & & & \vdots\\
\vdots & 0 & \ddots & \ddots & \ddots & \ddots & & \vdots\\
\vdots & & \ddots & \ddots & \ddots & \ddots & 0 & \vdots\\
\vdots & & & \ddots & -1 & 2 & -1 & 0\\
\vdots & & & & 0 & -1 & 2 & -1\\
0 & \cdots & \cdots  & \cdots & \cdots & 0 & -1 & 2\\
\end{pmatrix}
\end{equation}
\end{document}

enter image description here

  • @Mico Sure, here is a reference ece.umn.edu/~mihailo/software/lqrsp/mass_spring.html – sunspots Feb 21 '15 at 23:47
  • The matrix G is also referred to as a band matrix. – sunspots Feb 21 '15 at 23:48
  • Your proposed solution produces a symmetric matrix, whereas the OP appears to want to produce an asymmetric matrix with all elements above the diagonal equal to zero. – Mico Feb 22 '15 at 1:22
  • @Mico My entry is final. – sunspots Feb 22 '15 at 1:56
  • 1
    You can do whatever you want. An answer is usually considered to be more helpful, though, if it addresses the actual question that's been posed, rather than some other problem. – Mico Feb 22 '15 at 3:05

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