8

I am trying to use one equation in my thesis but that equation is long enough to fit in LaTeX format, I found one image but don't know how to convert that into LaTeX format, it uses some different symbols.

enter image description here

How to write this in LaTeX and make it small.

What I have tried:

\begin{equation}
\frac{\sum_{i j}\left(\begin{array}{l}{n_{i j}} \\ {2}\end{array}\right)-\left[\sum_{i}\left(\begin{array}{l}{a_{i}} \\ {2}\end{array}\right) \sum_{j}\left(\begin{array}{l}{b_{j}} \\ {2}\end{array}\right)\right] /\left(\begin{array}{l}{n} \\ {2}\end{array}\right)}{\frac{1}{2}\left[\sum_{i}\left(\begin{array}{l}{a_{i}} \\ {2}\end{array}\right)+\sum_{j}\left(\begin{array}{l}{b_{j}} \\ {2}\end{array}\right)-\left[\sum_{i}\left(\begin{array}{l}{a_{i}} \\ {2}\end{array}\right) \sum_{j}\left(\begin{array}{l}{a_{j}} \\ {2}\end{array}\right)\right] /\left(\begin{array}{l}{n} \\ {2}\end{array}\right)\right.}
\end{equation}

But it's appearing like this:

enter image description here

Edit:

%File: formatting-instruction.tex
\documentclass[letterpaper]{article}
\usepackage{aaai}
\usepackage{times}
\usepackage{helvet}
\usepackage{amsmath}

\usepackage{courier}
\frenchspacing
\setlength{\pdfpagewidth}{8.5in}
\setlength{\pdfpageheight}{11in}
\pdfinfo{
/Title (Insert Your Title Here)
/Author (Put All Your Authors Here, Separated by Commas)}
\setcounter{secnumdepth}{0}  
 \begin{document}
% The file aaai.sty is the style file for AAAI Press 
% proceedings, working notes, and technical reports.
%
\title{Thesis}
\author{Anonymous Author 
}
\maketitle
\begin{abstract}
\begin{quote}
AAAI creates proceedings, working notes, and technical reports directly from electronic source furnished by the authors. To ensure that all papers in the publication have a uniform appearance, authors must adhere to the following instructions. 
\end{quote}
\end{abstract}

\section{Model}

In this section we describe the architecture of our model.

\begin{equation}
\frac{\sum_{i j}\left(\begin{array}{l}{n_{i j}} \\ {2}\end{array}\right)-\left[\sum_{i}\left(\begin{array}{l}{a_{i}} \\ {2}\end{array}\right) \sum_{j}\left(\begin{array}{l}{b_{j}} \\ {2}\end{array}\right)\right] /\left(\begin{array}{l}{n} \\ {2}\end{array}\right)}{\frac{1}{2}\left[\sum_{i}\left(\begin{array}{l}{a_{i}} \\ {2}\end{array}\right)+\sum_{j}\left(\begin{array}{l}{b_{j}} \\ {2}\end{array}\right)-\left[\sum_{i}\left(\begin{array}{l}{a_{i}} \\ {2}\end{array}\right) \sum_{j}\left(\begin{array}{l}{a_{j}} \\ {2}\end{array}\right)\right] /\left(\begin{array}{l}{n} \\ {2}\end{array}\right)\right.}
\end{equation}



\end{document}
  • 3
    Please provide an MWE which reproduce your problem. Code fragment is not very helpful for helping you .... – Zarko Oct 22 at 7:25
  • I already provided the code. – Aaditya Ura Oct 22 at 8:13
  • @AadityaUra no providing a fragment just makes it hard for people to help you, please provide a test document. In particular you are asking how to make the equation fit without giving any information about how wide your column is. – David Carlisle Oct 22 at 8:17
  • @DavidCarlisle please check – Aaditya Ura Oct 22 at 8:32
  • @Zarko Please check – Aaditya Ura Oct 22 at 8:32
13

If I change \usepackage{times} into \usepackage{mathptmx} in your code and also the equation into

\begin{equation}
\frac{
  \sum_{ij}\binom{n_{ij}}{2}-\bigl[\sum_{i}\binom{a_{i}}{2} \sum_{j}\binom{b_{j}}{2}\bigr]\big/\binom{n}{2}
}{
  \frac{1}{2}\bigl[\sum_{i}\binom{a_{i}}{2}+\sum_{j}\binom{b_{j}}{2}\bigr]-
  \bigl[\sum_{i}\binom{a_{i}}{2} \sum_{j}\binom{a_{j}}{2}\bigr]
  \big/\binom{n}{2}     
}
\end{equation}

I get (dummy text added for context)

enter image description here

The output is even better if I change \usepackage{mathptmx} into

\usepackage{newtxtext,newtxmath}

enter image description here

If you want the description texts,

\begin{equation}
\overbrace{\mathit{ARI}}^{\hidewidth\substack{\text{Adjusted}\\\text{Index}}\hidewidth}=
\frac{
  \overbrace{\textstyle\sum_{ij}\binom{\vphantom{b}n_{ij}}{2}}^{\text{Index}}
  -
  \overbrace{\textstyle\bigl[\sum_{i}\binom{a_{i}}{2} \sum_{j}\binom{b_{j}}{2}\bigr]\big/\binom{n}{2}}%
    ^{\text{Expected Index}}
}{
  \underbrace{\textstyle\frac{1}{2}\bigl[\sum_{i}\binom{a_{i}}{2}+\sum_{j}\binom{b_{j}}{2}\bigr]}%
    _{\text{Max Index}}
  -
  \underbrace{\textstyle\bigl[\sum_{i}\binom{a_{i}}{2} \sum_{j}\binom{a_{j}}{2}\bigr]\big/\binom{n}{2}}%
    _{\text{Expected Index}}
}
\end{equation}

enter image description here

  1. With \hidewidth, the description above “ARI” takes no space; it is also split into two lines not to intrude the right-hand side.

  2. \textstyle is necessary, because \overbrace and \underbrace force \displaystyle

  3. The \vphantom{b} has been added to set “Index” at the same height as the other description.

  • 1
    I can't give more than one upvote :P – Aaditya Ura Oct 22 at 9:27
  • @AadityaUra I've just added a small change to the solution with the braces. – egreg Oct 22 at 9:28
  • 1
    @AadityaUra There is also the mine :-) – Sebastiano Oct 22 at 9:28
  • @AadityaUra Well, for advice like “use mathptmx or NewTX we're here. For learning how to type mathematics, experience and desire to learn. I'd usually avoid those over/underbraces and explain the parts separately before stating the equation. – egreg Oct 23 at 19:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.