# How I can write this equation in LaTeX

I’m still a beginner to LaTeX, and I don’t know how to write this equation.

• Welcome to TeX.SE! Did you read an introduction to LaTeX? Please show us what you have tried so far ... – Kurt Jan 13 at 3:37
• Isn't this the same question you asked a day ago? Please advise if this impression is incorrect. – Mico Jan 13 at 3:42
• To write equations simply the easiest way is to use LyX because it allows you to view the rendering live. Watch this very short video: How to use mathematical formula editor in LYX - LaTeX Home page of Lyx LyX – The Document Processor – AndréC Jan 13 at 8:13

\documentclass{article}

\usepackage{amsmath}

\begin{document}

$\mathrm{ASD}(P_{\text{ref}}, P_{\text{auto}}) = \frac{1}{\lvert P_{\text{ref}} \rvert} \sum_{p \in P_{\text{ref}}} d(p, P_{\text{auto}})$

\end{document}


This is an expanded version of @Werner's answer.

Welcome to TeX.SE!

I can see that you are in a great hurry, so I decide to post an answer here (in additional with an upvote). However, you just have to spend about 15 minutes reading and practicing to get what you want.

\text{ASD}(P_\text{ref},P_\text{auto})=\frac{1}{\vert P_\text{ref}\vert}\sum_{p\in P_\text{ref}}d(p,P_\text{auto}),


This is another equation (which you posted yesterday -- I'm sorry if I remember it wrong:

\text{MSD}(P_\text{ref},P_\text{auto})=\max\left\{\max_{q\in P_\text{ref}}d(q,P_\text{auto}),\max_{q\in P_\text{auto}}d(q,P_\text{ref})\right\},


In a bit more advanced level (it is still basic) you should define your own \pref and \pauto to avoid using too many P_\text{ref} and P_\text{auto}. This is a complete code:

\documentclass{article}
\usepackage{amsmath}
\newcommand{\pref}{P_\text{ref}}
\newcommand{\pauto}{P_\text{auto}}
\begin{document}
$\text{ASD}(\pref,\pauto)=\frac{1}{\vert\pref\vert}\sum_{p\in\pref}d(p,\pauto),$
And
$\text{MSD}(\pref,\pauto)=\max\left\{\max_{q\in\pref}d(q,\pauto),\max_{q\in\pauto}d(q,\pref)\right\},$
\end{document}