Introduction to LaTeX (Part 1)

Abstract: LaTeX is a cool type setting system that many use especially when generating documents that contain fancy formulas and mathematical/Greek symbols. Many use this program when writing the thesis/dissertation and when giving presentations. Many journals require authors to use the LaTeX format when submitting articles. Also, many instructors and TAs find it convenient to use LaTeX to create handouts, lecture notes, and of course, those notorious examinations. It is a very versatile program and a useful tool for both master's and doctoral students. This talk will start from scratch and give a very basic introduction to using LaTeX and some of its most useful features.

What is LaTeX?
LaTeX (pronounced "lay-tek" or "lah-tek") is a typesetting language. LaTeX was created for the purpose of typesetting text and mathematical formulas.

LaTeX is not a word processing program. Unlike programs like MS Word where your document is produced "on the fly" through a "What You See Is What You Get" format, LaTeX files need to be processed or compiled first before the final product can be viewed.
Useful in typesetting:
- class handouts and examinations
- homework assignments
- presentation slides
- curriculum vitae
- articles for journals
- thesis/dissertation
- reports and books
LaTeX Software: PC versus UNIX
LaTeX is freely available. On our UNIX system LaTeX will automatically be found. For those interested in downloading LaTeX on a PC, visit this link. At this link you will find information on MikTeX, which is one of the more popular implementations used on the PC. Once the LaTeX "engine" (like MikTeX) is installed, you will find it useful to use a program that conveniently links the steps of editing, compiling, and viewing your LaTeX file. One such program which is freely available is Crimson Editor.

For the remainder of this presentation, we will focus on using our UNIX system to create a LaTeX document. Once you understand the main principles of creating a LaTeX file in UNIX, you will have no troubles creating files on the PC environment.
Getting Started
In an Xterm window type:
```
    > add tetex [RETURN]
```
This will give you access to the LaTeX related commands we will need. You will need to issue this command whenever you start a new Xterm session.

For the purposes of this presentation, let us create a subdirectory (called latex) in your UNIX account where we will store our example LaTeX files.

In the same Xterm window used above type:
```
    > cd [RETURN]
    > mkdir latex  [RETURN]
    > cd latex [RETURN]    
```
LaTeX Fundamentals
When creating a LaTeX document, cycle through these steps:
1. Edit the text file (saved as myfile.tex)
2. Process the file with the LaTeX program and this will create a device independent (.dvi) file.
3. View the .dvi file with a DVI viewer.
4. Return to step 1 to make further changes.
5. If no further changes are to be made, convert the .dvi file into a format like PS (postscript) or PDF (Adobe Portable Document Format) in order to print.
Implementation in UNIX
1. Edit the text file
  In your favorite text editor (e.g. Nedit), modify your LaTeX file and ensure you save the file with the .tex extension (assume the name of the LaTeX file is myfile.tex). In an Xterm window, type:
```
          > nedit myfile.tex & [RETURN]
      
```
  Notice the ampersand (&) at the end of the command. This will keep the Xterm window free for future use. This will be the one and only time the xdvi command needs to be issued.
2. Process the file
  In an Xterm window, ensure the working directory is set to where the LaTeX file is located. Assuming the add tetex command has already been issued, type:
```
          > latex myfile.tex [RETURN]
      
```
  This will create a device independent (.dvi) file.
3. View the .dvi file
  In the same Xterm window, type:
```
          > xdvi myfile.dvi & [RETURN]
      
```
  Notice again the use of the ampersand (&).
4. Return to step 1 for further changes
5. Once finished, convert file to PS or PDF
  (to be discussed later)
Here is what your typical UNIX session will look like.
Our First Example

Click on the LaTeX template file link below and save it locally in your newly created latex subdirectory.

LaTeX Template File

Once it has been saved, follow steps 1 through 4 as stated above to compile and view your sample LaTeX document.

Standard LaTeX File

The overall form of a typical LaTeX file will look like the following:


    
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%   Sample LaTeX Document
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
\documentclass[12pt]{article}
\usepackage{graphicx}
    
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%   The Preamble

\setlength{\oddsidemargin}{0.0in}
\setlength{\evensidemargin}{-0.25in}
\setlength{\topmargin}{-0.75in}
\setlength{\headheight}{0.20in}
\setlength{\headsep}{3ex}
\setlength{\parskip}{2.3ex}
\setlength{\parindent}{0.0in}
\setlength{\baselineskip}{2ex}
\setlength{\textheight}{9in}
\setlength{\textwidth}{6.8in}

%   The Preamble
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


\begin{document}

    % Body of the document

\end{document}

Use a comment by preceding a string of text with the percent (%)
\documentclass[font size]{style} font size = 10pt, 11pt, 12pt
style = article, report, book
\usepackage{graphicx} -many many packages to choose from (graphicx is used to import images)
-you can add and utilize multiple packages at the same time
The Preamble
This is where you can specify margin sizes, line spacings, paragraph spacings, and other page layout details. Here you can also specify shortcuts for cumbersome LaTeX commands (to be discussed later).
Extra spaces between words on a given line do not appear in the final output.
Extra line breaks between paragraphs do not appear in the final output.

The Language of LaTeX

As with any computing language (like HTML) LaTeX has its own set of key words and language structure. However, unlike some languages, LaTeX is case sensitive. Most commands in LaTeX begin with the backslash (\).

Emphasizing Text, Other Fonts, and Font Sizes

Three basic ways to emphasize text is have it appear with an underline, in italics, or in bold. Here are the commands to implement this in LaTeX:

LaTeX Code	Final Output
`\underline{a string of text}`	a string of text
`\emph{a string of text}`	a string of text
`\textbf{a string of text}`	a string of text

Here are commands to generate other fonts and font sizes. By adding other packages, you can have access to many more fonts.

Math Symbols

When using math related keywords, it is necessary to specify the math environment. For example, if you wanted to express the sum of the Greek lower case letters alpha, beta, and gamma, you can type any of the following:

\begin{math} `\alpha + \beta + \gamma` \end{math}	$ `\alpha + \beta + \gamma` $
\[ `\alpha + \beta + \gamma` \]	$\alpha + \beta + \gamma$

Here is a compilation of keywords to generate some other symbols. Note that some of the symbols require the use of certain packages.

Some examples of math related expressions:

LaTeX Code	Final Output
$x_{1}, x_{2}, x_{3}$	x₁, x₂, x₃ (subscript)
$y^{1}, y^{2}, y^{3}$	y¹, y², y³ (superscript)
$\sqrt{x+y}$	(square root of x+y)
$\frac{a}{b}$	(fraction of the form a over b)
$\int_{0}^{\infty} f(x) dx$	(integral of f(x), limits from 0 to infinity)
$\sum_{i=1}^{\infty} x_{i}$	(infinite sum of x_i using Sigma notation)

Example LaTeX code to be added to your original file

Other Environments

Aside from the math environment, there are many other environments in LaTeX that allow the user to create useful features such as tables, lists, equations, and so on.

Building a table

Suppose we would like to create the following table in LaTeX where each column is right justified.

Regression	beta₀	beta₁
Estimate	2.145	14.642
SD	1.451	4.395


\begin{tabular}{|r|r|r|}
\hline
Regression & $\beta_{0}$ & $\beta_{1}$ \\ \hline
Estimate   & 2.145       & 14.642 \\      \hline
SD         & 1.451       &  4.395 \\      \hline
\end{tabular}

Building a list

Suppose we would like to create the following list in LaTeX where each item is bulleted.

My Grocery List

Eggs
Butter
Bacon
Pasta


\underline{My Grocery List}
\begin{itemize}
   \item Eggs
   \item Butter
   \item Bacon
   \item Pasta
\end{itemize}

If the items of the list should be enumerated, use:


\underline{My Grocery List}
\begin{enumerate}
   \item Eggs
   \item Butter
   \item Bacon
   \item Pasta
\end{enumerate}

Making equations

When typesetting equations, it is often desirable to align a set of equations in a particular way. For example, when expanding an expression to equivalent forms, we usually align the equivalent forms in the same column. For example, consider the following expansion:

	(x + y)³
=	(x + y)(x + y)(x + y)
=	(x² + 2xy + y²)(x + y)
=	x³ + 2x²y + xy² + x²y + 2xy² + y³
=	x³ + 3x²y + 3xy² + y³

We can create this same alignment of equations with the following:


\begin{eqnarray}
&   & (x+y)^3 \\
& = & (x+y)(x+y)(x+y) \\
& = & (x^2 + 2xy + y^2)(x+y) \\
& = & x^3 + 2x^2 y + xy^2 + x^2 y + 2xy^2 + y^3 \\
& = & x^3 + 3x^2 y + 3xy^2 + y^3 
\end{eqnarray}

The eqnarray environment is just like a tabular environment where it has exactly 3 columns. Note, however, that within this environment the math mode is already in effect (no need to surround expressions with $...$). Once compiled, each line will automatically be numbered by LaTeX. To suppress the numbering scheme, use instead \begin{eqnarray*} ... \end{eqnarray*}

Example LaTeX code to be added to your original file

Customizing Commands with Shortcuts
Suppose in your LaTeX document you know you will be making many references to the exact form of the pdf of the normal distribution which, in LaTeX code, looks like:
\frac{1}{\sqrt{2\pi}\sigma}e^{-(x-\mu)^2/(2\sigma^2)}
Even with a text editor that is capable of cutting/pasting, the repetitive act of placing this long code can become cumbersome. Instead, we can create a shortcut by defining a new keyword in the preamble to represent this complicated code. It would be wise to select a keyword that is not already used by LaTeX (let us use npdf to represent the normal pdf).

Somewhere in the preamble, we can place the following line:
\newcommand{\npdf}{\frac{1}{\sqrt{2\pi}\sigma}e^{-(x-\mu)^2/(2\sigma^2)}}
Then, anywhere in the midst of the body of the document, we can invoke this shortcut by simply typing \npdf (must be in math mode).
Importing Images (Postscript)

To import postscript images we need to use a package like graphicx. Assuming that the statement \usepackage{graphicx} appears in the preamble, if we have a postscript file named graph_1.ps, we can import this image with the following statement placed in the body of the LaTeX file:
\includegraphics[width=2.5in]{graph_1.ps}
Sometimes, LaTeX will have trouble importing the image in the exact preferred location of your document. Consult a LaTeX reference text for additional information on how to remedy this problem.

Two very flexible and powerful programs available on UNIX that can create postscript images are xfig and tgif. To use tgif you will first need to add the goodies locker (type add goodies at the UNIX prompt) and then type tgif.

To use xfig, simply type xfig at the UNIX prompt. Launch xfig and export a simple picture as a postscript file.

Example Postscript Image Use the right mouse button to choose "save link as" or "save target as".

Example LaTeX code to be added to your original file
Converting to Postscript or PDF

Now that you have completed your masterpiece, convert it to postscript or PDF to be able to view the printed form.

In the Xterm window type:
dvips myfile.dvi
This will convert the .dvi file into postscript format (saved as myfile.ps). Print the file with the command lpr myfile.ps. If the printed form looks misaligned, you can make adjustments with:
dvips -O 0.xin,0.yin myfile.dvi
Above we are using the -O switch (capital letter `oh') to adjust the location of the image 0.x inches along the horizontal direction and 0.y inches in the vertical direction (you can use negative values as well). If this does not help, you may need to return to the preamble section of the LaTeX file and make adjustments there.

You can create a Adobe PDF file by converting the postscript file. In the Xterm window type:
add acrobat distill <myfile.ps> myfile.pdf

Reference Texts

Many to choose from -- here are only some:

LaTeX : A Documentation Preparation System
User's Guide and Reference Manual
Author: Leslie Lamport, Duane Bibby(Illustrator)
Format: Trade Paperback
Publication Date: August 1994
ISBN: 0201529831

The Latex Companion
Author: Michel Goossens, et al
Format: Trade Paperback
Publication Date: January 1994
ISBN: 0201541998

A Guide to Latex: Document Preparation for
Beginners & Advanced Users
Author: Kopka, Helmut
Format: Softcover
Publication Date: 2/1/1999
ISBN: 0201398257

Latex for Everyone: A Reference Guide and Tutorial
for Typesetting Documents Using a Computer
Author: Jane Hahn
Format: Paperback
Publication Date: February 1993
ISBN: 0136059082

Reference Sites
Introduction to LaTeX Session 2

\begin{math} `\alpha + \beta + \gamma` \end{math}	\( `\alpha + \beta + \gamma` \)
\[ `\alpha + \beta + \gamma` \]	$\alpha + \beta + \gamma$