Tutorial 17.1 - LaTeX

17 Nov 2018

About

Engines

Installing

Different platforms (Windows, MacOSX and Linux) present very different environments and requirements. Accordingly, different Tex distributions are available for each of these platforms:

Windows

1. Goto the MiKTeX distribution download page
2. Follow the link to download an appropriate MiKTeX installer (typically the one it recommends is the most appropriate for your system)
3. Double click on the downloaded executable to Install. You will need to provide affirmation that the installer is to be trusted when prompted by Windows)

MacOSX

1. Using Safari, goto the MacTeX distribution page
2. Follow the link to download the MacTeX.pkg (approximately 2.1GB)
3. Double click on the downloaded file to Install

Linux

1. For Debian based systems, sudo apt-get install texlive-xetex texlive-fonts-extra texlive-science

First glimpse

Simple example

LaTeX code

PDF result

\documentclass[a4paper,12pt]{article} \begin{document} \begin{document} \section{A section}\label{sec:s1} This is a minimum \LaTeX~document. Notice that the first line of this paragraph is not indented.\\ This paragraph has \textbf{bold}, \textit{italic}, \underline{underline} words. $$\sum{\frac{(\mu - \bar{x})^2}{n-1}}$$ \section{Second section} Where we can refer to section \ref{sec:s1} \end{document}

Compiling

Linux and MacOSX users typically know how to obtain a terminal as many of the power tools and applications on these systems are accessed that way. However, Windows users are often less familiar with command driven tools. To obtain a command prompt in Windows, click the start button and type cmd or command in the search box.

Navigate to where the example.tex file you created earlier is located and enter the following command.

  xelatex example.tex

• example.aux - this file contains information for the LaTeX engine about the numbering and cross-referencing contained in your document. The xelatex tool automatically reads the contents of this file at the end of the source code (example.tex preamble (before reading the document body). Clearly, the first time you run xelatex on your example.tex file, it will not exist and thus no cross-referencing information will be available to the LaTeX engine to allow it to insert cross-references in the document. A pair of question marks (??) will appear in the place of the cross-reference.
  
  
  

  As xelatex moves through the source file, numbering and cross-referencing information is added to this *.aux file. Next time xelatex is run on the source file, the cross-referencing information will be available and thus correctly inserted into the final document. Hence xelatex should always be run multiple times on the source file. Similarly, one the source file has been edited, numbering and cross-referencing information could be out of date and thus xelatex should be run multiple times.

  In reality, it is typically sufficient to regularly run xelatex once after a major edit (just to ensure no errors have crept into the source file) and then only run xelatex multiple times once the document is complete.

• example.log - this file is a copy of all the text that danced across the terminal. It is a log of all the steps, issues and errors performed and encountered by xelatex whilst processing your source file and other auxiliary files (such as example.aux). The log file is somewhat cryptic and takes a great deal of getting used to before the messages can be used to effectively debug issues.

Simple LaTeX markup

Special characters and control sequences

For example, to italicize a word or series of words, we could say:

  \textit{this is emphasized}

Groups

Curly braces also define groups. In essence, they define a region over which the influences of various actions are limited. That is they define the scope of any actions. For example, if a command is issued within a pair of curly braces to italicize text, then all text within the group (and not outside the group) will be italicized.

Control sequences - functions

Control sequences (which act like functions) typically begin with a backslash (\) and are followed by a string or characters. In the above example, the control sequence (\textit) acts like a function that requires a single argument (the text to be italicized). As another example of a control sequence, \LaTeX inserts a specially formatted label of the word LaTeX and does not apply to any of the other text (and thus need not be followed by curly braces surrounding text).

Some control sequences require one or more arguments (input). These arguments are supplied within curly braces. Some control sequences also support optional arguments that can be supplied to alter the default behaviour. Optional arguments are supplied withing square braces ([]). Therefore the general syntax of a control sequence is:

  \commandname[option1,option2,...]{argument1,argument2,...}

Switches

LaTeX code	PDF result
\documentclass{article} \begin{document} Correct usage\\ \verb=\emph= is a command with an argument,\\ \verb=\em= is a switch.\\ \emph{emphasized text}, this part is normal\\ {\em emphasized text}, this part is normal\\ Incorrect usage\\ \\em emphasized text, this part is normal\\ \\em{emphasized text}, this part is normal\\ \end{document}

Comments

Special characters

The backslash (\) character therefore has special meaning within LaTeX code (it defines a control sequence). Other special characters include:

• { and } - which signify grouping. That is all the characters they enclosed are treated with the same formatting. They can also define a single argument to a control sequence.
• $ - the dollar sign is used to define mathematics mode in which special expressions are converted to mathematical formulae.
• _ and ^ - underscore and hat are used in mathematics mode to specify subscript and superscript respectively.
• % - percentage sign is used to define a comment. All characters on a line following a % will be ignored by the LaTeX engine.
• ~ - tilde is used to indicate a non-breaking space. That is it indicates that there should be a space between two characters, yet the characters should remain on the same line.
• & - ampersand is used in tables to indicate the position of columns.
• # - hash symbol is used when defining control sequences (in particular, it is used to indicate how many arguments are required by a control sequence).

Environments

An example of an environment is a enumerated list. This environment not only defines the spacing and indenting rules for each item of the list, it also manages a series of counters and number formatters so as to number the items correctly and hierarchically.

Environments have the following format:

  \begin{environmentname}
  content to which the environment is applied
  \end{environmentname}

Ordinary text and punctuation

LaTeX understands that sentences separated by a blank line represent separate paragraphs and paragraphs (other than the first in a section) are indented.

Whilst each of the rules can be modified, the defaults have been specifically chosen to adhere to typographical standards.

LaTeX code

PDF result

\documentclass{article} \begin{document} A comprehensive set of rules within the LaTeX system take care of most simple paragraph and punctuation formatting. For example, the system works out the optimal spacing of words and line breaks for the width of the document so as to yield aesthetically pleasing paragraphs. It also understands that a full stop is an end of sentence marker and thus inserts extra space between it and the next word. LaTeX understands that sentences separated by a blank line represent separate paragraphs and paragraphs (other than the first in a section) are indented. Whilst each of the rules can be modified, the defaults have been specifically chosen to adhere to typographical standards. \end{document}

Blank spaces and line breaks (carriage returns)

Blank spaces following a control sequence are ignored. Therefore in order to force a space between a control sequence and the next character, it is necessary to use the \ (a backslash followed by a space) control sequence or else use the ~ non-breaking space specifier (as was done in an earlier example).

LaTeX code	PDF result
\documentclass{article} \begin{document} This nonsense sequence of words with somewhat ridiculous spacing and line breaks will be handled sensibly by the \LaTeX\ engine.\\[10pt] Lucky something is sensible! \end{document}

Paragraph justification

\begin{flushleft}
...
\end{flushleft}

\begin{flushright}
...
\end{flushright}

\begin{center}
...
\end{center}

Quotation marks

Furthermore, whilst the undirected double quotation mark (") can be used to represent double right quotation marks, it is more advisable to use two consecutive single right quotation marks. The same applies to double left quotation marks.

LaTeX code	PDF result
\documentclass{article} \begin{document} This nonsense sequence of words with somewhat ridiculous spacing and line breaks will be handled sensibly by the \LaTeX\ engine.\\[10pt] Lucky something is sensible! \end{document}

Dashes

• hyphens for separating word prefixes
• en-dashes for signifying number ranges
• em-dashes for signifying punctuation dashes

LaTeX code	PDF result
\documentclass{article} \begin{document} A hyphen is used in work prefixes such as non-parametric.\\ An en-dash is used to signify number ranges such as 22--43.\\ An em-dash is used as a punctuating dash --- like this. \end{document}

Font styles and sizes

Brief changes to font styles within a block of text can be effective at emphasizing or applying different meanings to characters. Common text modifier styles are: italic, bold, strikethrough and underline. Similarly, different font families are also used to imply different meaning. For example, courier font, roman or serif font, sans serif font.

LaTeX has a control sequence called \emph{} that emphasizes (usually italics) the text within the curly braces. Further control of font styles is provided via a series of control sequences beginning with \text as described in the following table. There are also a couple of other common styles that have their own control sequences. Similarly, there are also font declaration control sequences that apply their modification to all subsequent text until the next font declaration (or until the end of a group - recall that groups are strings of characters between curly braces).

The above modifiers can be nested within one another for example to produce bold, italic text (\textbf{\textit{bold, italic text}}).

There are a useful set of switches for altering font sizes in aesthetic increments.

Accents and special characters

There are also control sequences for producing ligatures and other special characters.

Document structure

• the preamble - comprising all the control sequences etc that effect the entire document. Often numerous settings and user defined commands are defined in this section. Formally it comprises:
  • a document class definition - that specifies the type of document to produce and some of the global options for the document. For example:
    \documentclass[a4paper,12pt]{article}
  • links to packages that provide additional functionality and command sequences as well user defined settings and other styling specifications
• the document - the main body of the document containing the content. The main body of text (the document) is contained between beginning and end of document markers. For example:

  +\n begin{document}
  ...
  +\n end{document}
    

Document classes

LaTeX compiles a document based on a document class. A document class defines the broad type of document and thus establishes a set of appropriate styling and formatting rules. The most common document class are listed in the following table.

Article

Report

Book

Class options

Each class has a number of common optional arguments that can be supplied in order to refine the overall look, style and format of the document within the board document class. As optional arguments, these are supplied in square braces ([]) before the compulsory argument.

Packages

Packages are external files that provide additional sets of macros (settings) that extend the functionality of LaTeX. Modern TeX distributions come with a large number of packages pre-installed.

In order to make a packages' settings available for use in your document, you need only provide the name of the package as an argument to the \usepackage{} control sequence. For example, to make the graphicx package (that provides routines for inserting external graphics into a document) available, we would add the following to the preamble:

  \usepackage{graphicx}

Some packages have optional arguments. As with other optional arguments, these can be engaged by specifying them in square braces prior to the curly braces containing the package name.

Top matter

Most documents begin with a title as well as other meta data such as the author(s), their address and production dates. In LaTeX this is referred to as top matter. The top matter comprises of a number of fields (control sequences) allow with a single control sequence (\maketitle) that indicates where the top matter should appear in the document. Specifically, the \maketitle control sequence, gathers up the following fields and generates a title at its position.

\author{Dr. I. C. Git}\\1 Pratt St\\Loserville}

\author{Dr. I. C. Git \and Dr. I. P. Daily}

Sections

These control sequences take a single compulsory argument reflecting the content of the heading or subheading title. They also allow a single optional argument that defines an abbreviated title for use in tables of contents and running page headers.

The control sequences automatically look after the formatting of spacing, font and font size of heading title. They also manage a series of incremental counters and automatically number the section headings accordingly.

LaTeX code	PDF result
\documentclass{article} \begin{document} \section{Introduction} Bla Bla Bla about the context and aims of this study. \section{Methods} \subsection[Study site]{Study site description} A nice description of the sites and subjects used in the study \subsection{Data collection} \end{document}

The book document style has an additional \chapter control sequence for defining chapters. Chapters operate above the level of sections and cause a page break such that a chapter starts on a new odd numbered (right hand side) page.

Table of contents

A table of contents can be generated by placing the \tableofcontents control sequence at the place you wish the table of contents to appear. An example of the format and style of a table of contents can be seen in the book and report examples in the Document structure section above.

Table of contents entries are made up of section (subsection etc) headings, their numbers and page numbers and are progressively collected into a *.toc file as the source document is processed. This *.toc file is then read at the time that the \tableofcontents control sequence is encountered. As \tableofcontents usually appears in the document prior to the sections, on the first pass of the LaTeX engine, the table of contents will be blank. Processing the document a second time will correct this.

There is also a \listoffigures control sequence that generates a list of figures.

Space, units, lengths and dimensions

There are three fixed-length spacing control sequences, that can be applied when in vertical mode (e.g. when between paragraphs rather than in the middle of a sentence which is horizontal mode).

• \smallskip - inserts a small vertical space
• \medskip - inserts a medium vertical space
• \bigskip - inserts a large vertical space

The \hspace{} and \vspace{} control sequences have a single compulsory argument, the size of the blank space expressed in one of LaTeX's recognized units:

There are a number of lengths within LaTeX. This behave like variables in that they store a length of some dimension and can be modified automatically or manually. These lengths can be used anywhere a measurement is required as an argument.

Lengths are specified as a number followed by a unit. For example, the following would be a length of exactly 12pt.

  12pt

  12pt plus 3pt minus 2pt

Some of the more useful lengths relate to the various dimensions of the document such as the page height and width as well as the width and height of a line of text within a page. These lengths and dimensions are illustrated in the following diagram. Note, these lengths assume a2paper article class.

Diagram	Length parameter
	one inch + \hoffset
	one inch + \voffset
	\oddsidemargin = 53pt
	\topmargin = 17pt
	\headheight = 12pt
	\headsep = 25pt
	\textheight = 598pt
	\textwidth = 345
	\marginparsep = 11pt
	\marginparwidth = 57pt
	\footskip = 30pt
	\paperheight = 845.0684pt
	\paperwidth = 597.50787pt

Length parameter	Description
\parindent = 0.0pt plus 1.0pt	Length that a paragraph is indented
\parskip = 15pt	Vertical space between paragraphs
\baselineskip = 12pt	Vertical space between lines in a paragraph
\baselinestretch	Baselineskip multiplying factor
\columnsep = 10pt	Distance between columns in a multicolumn page layout
\columnwidth = 431.43306pt	The width of a column of text
\evensidemargin = -72.26999pt	The width of the margin on an even page
\linewidth = 431.43306pt	The width of a line
\oddsidemargin = -72.26999pt	The width of the margin on an odd page

Manipulating lengths

The value of a length can be queried by adding the control sequence \the directly in front of the relevant length control sequence. For example, the get the width of a line of text:

  \the\textwidth

There are numerous ways that lengths can be set. For example, the following table list the different ways to set a length (some of these involve setting the width of a line of text, \textwidth).

Lists

• enumerate lists for numbered lists
• itemize lists for un-numbered, bullet lists
• description lists for descriptive or definition lists

+\n begin{enumerate}
+\n item ...
+\n end{enumerate}
  

LaTeX code

PDF result

... \begin{enumerate} \item Point 1. This is a numbered list \item Point 2. Note how numbering is automatic \begin{enumerate} \item Subpoint 1. Note how indenting is automatic \item[b] Subpoint 2 (note I have overridden the item counter) \end{enumerate} \end{enumerate} \begin{itemize} \item Point 1. This is a bullet list \item Point 2. \begin{itemize} \item Subpoint 1 \item[\dag] Subpoint 1 (I have overridden the bullet) \end{itemize} \end{itemize} \begin{description} \item[enumerate] A numbered list \item[itemize] A bullet list \item[description] A definition list (such as this one!) \end{description} ...

Diagram	Length parameter
	\topsep = 8.0pt plus 2.0pt minus 4.0pt
	\parskip = 0.0pt plus 1.0pt
	\partopsep = 2.0pt plus 1.0pt minus 1.0pt
	\labelwidth = 20.00003pt
	\labelsep = 5pt
	\itemindent = 0pt
	\listparindent = 0pt
	\leftmargin = 25.00003pt
	\rightmargin = 0pt
	\itemsep = 4.0pt plus 2.0pt minus 1.0pt
	\parsep = 4.0pt plus 2.0pt minus 1.0pt

Graphics

When using the xelatex TeX engine, the \includegraphics graphics driver supports each of the following graphics formats:

• JPG - best choice for photographs
• PNG - as a result of its superior compression and handling of transparency, this is the best choice for screen captures and diagrams (if vector graphics unavailable)
• PDF - best for scalable (vector) graphics and diagrams as well as documents
• EPS - as for PDF, yet it is a larger language

The optional arguments are supplied between square braces (e.g. [width=, height=]) and comprise the following:

• if no optional arguments are supplied, the image is included in its actual size
• if either width OR height are supplied, then the image is scaled to that supplied dimension preserving the aspect ratio
• if width and height are both supplied, then the image is resized to satisfy both dimensions (possibly distorting the aspect ratio).

The compulsory argument {} is for the full (or relative) path and name of the image to insert

LaTeX code

PDF result

\documentclass{article} \usepackage{graphicx} \begin{document} Include the figure such that it is scaled to the width of a line of text.\\ \includegraphics[width=\linewidth] {images/gelman1.png}\\ PDF scaled to half the width of a line of text\\ \includegraphics[width=0.5\linewidth] {images/graphics-tut5_1-axisposPlot.pdf}\\ JPG image scaled to a width of 3cm\\ \includegraphics[width=3cm] {../images/logo.jpg}\\ \end{document}

LaTeX code

PDF result

\documentclass{article} \usepackage{graphicx} \begin{document} Rotate the image 30 degrees and scale it to a width of 3cm (left figure)\\ Scale the image to a width of 3cm and then rotate it by 30 degrees (right figure)\\ \includegraphics[angle=30,width=3cm] {../images/logo.jpg} \includegraphics[width=3cm,angle=30] {../images/logo.jpg}\\ Scale the image to 1.5 (50\% bigger)\\ \includegraphics[scale=1.5] {../images/logo.jpg}\\ \end{document}

Vector graphics within LaTeX

As well as importing graphics from external sources, there is a very rich set of tools for generating scalable vector graphics within LaTeX. Arguably the most comprehensive of these toolsets is the PGF/Tikz tools.

The Portable Graphics Format (PGF) is actually a graphics layer and language for producing graphics. Tikz provides a syntax layer that sits on top of PGF making it easier to generate PGF syntax.

As this is a very substantial topic, PGF/Tikz will be the subject of a dedicated tutorial.

Tables

Tables are relatively complex structures and there are a number of special table types (such as multi-page tables) that pose sufficient challenges to warrant equally specialized packages to facilitate their creation. Nevertheless, most table environments are variations on the tabular environment. Hence, we will start by exploring this environment.

The tabular environment

The tabular environment arranges content of each line (row) into columns, the widths of which are determined automatically. The tabular environment has the general form of:

  \begin{tabular}[pos]{table spec}
  ...
  \end{tabular}

The optional pos argument can be used to indicate the relative vertical alignment of the table relative to the baseline of the surrounding text and thus is only necessary when a table is to line up next to another table, graphic or text.

The table spec argument defines the alignment of each column in the table. The widths of columns are automatically determined based on the contents of each column. However, tables cannot be wider than the width of a line of regular text, and thus over full content will be truncated. To fix the width of a column to a specific size and force the content to wrap (similar to regular paragraph text), the table spec argument also offers a special p{'width'} column specifier. The 'width' is any valid length measurement.

Within the table itself, the following control sequences are used:

Simple examples

LaTeX code	PDF result
\documentclass{article} \begin{document} \begin{tabular}{lcr} \hline Column A&Column B&Column C\\ \hline Category 1&High&100.00\\ Category 2&High&80.50\\ \hline \end{tabular} \end{document}

LaTeX code	PDF result
\documentclass{article} \begin{document} \begin{tabular}{l||c|r} \hline Column A&Column B&Column C\\ \hline Category 1&High&100.00\\ Category 2&High&80.50\\ \hline \end{tabular} \end{document}

LaTeX code	PDF result
\documentclass{article} \begin{document} \begin{tabular}{lcr} \hline Column A&Column B&Column C\\ \cline{2-3} Category 1&High&100.00\\ Category 2&High&80.50\\ \hline \end{tabular} \end{document}

LaTeX code	PDF result
\documentclass{article} \begin{document} \begin{tabular}{l||@{}c|@{\hspace{1.5cm}}r} \hline Column A&Column B&Column C\\ \hline Category 1&High&100.00\\ Category 2&High&80.50\\ \hline \end{tabular} \end{document}

Spanning

Cells spanning multiple columns

LaTeX code	PDF result
\documentclass{article} \begin{document} \begin{tabular}{lcr} \hline &\multicolumn{2}{c}{Multi}\\\\ \cline{2-3} Column A&Column B&Column C\\ \hline Category 1&High&100.00\\ Category 2&High&80.50\\ \hline \end{tabular} \end{document}

Cells spanning multiple rows

LaTeX code	PDF result
\documentclass{article} \\usepackage{multirow} \begin{document} \begin{tabular}{lcr} \hline Column A&Column B&Column C\\ \hline \multirow{2}{*}{Category 1}&High&100.00\\ &High&95.00\\ \multirow{2}{*}{Category 2}&High&80.50\\ &High&82.00\\ \hline \end{tabular} \end{document}

Hierarchical tables

• use \multicolumn{}{}{} to set the sub-table headings
• use \cline{} to put horizontal lines above the sub-table headings
• place an additional (empty) column between each of the sub-tables. This ensures a gap in the horizontal lines

LaTeX code
\documentclass{article} \usepackage{multirow} \begin{document} \begin{document} \begin{tabular}{lrrrcrrr} \hline &\multicolumn{3}{c}{Winter}&&\multicolumn{3}{c}{Summer}\\ \cline{2-4}\cline{6-8} Term&Slope&d.f.&P-value&&Slope&d.f.&P-value\\ \hline A&1.24&22&0.011&&2.62&22&$<$0.001\\ B&-3.87&23&0.026&&-2.28&23&0.001\\ \hline \end{tabular} \end{document}
PDF result

Fixed column widths and text wrapping

LaTeX code	PDF result
\documentclass{article} \begin{document} \\begin{tabular}{lcp{3cm}} \\hline Column A&Column B&Column C\\\\ \\hline Category 1&High&A much larger block of text that would otherwise extend outside of the bounds of the page\\\\ Category 2&High&This one is not so large\\\\ \\hline \\end{tabular} \end{document}

Colors in tables

Colored table rows

LaTeX code	PDF result
\documentclass{article} \usepackage[table]{xcolor} \begin{document} \rowcolors{2}{white}{lightgray} \begin{tabular}{lcr} \hline Column A&Column B&Column C\\ \hline Category 1&High&100.00\\ Category 1&High&95.00\\ Category 2&Low&80.50\\ Category 3&Low&82.00\\ \hline \end{tabular} \end{document}

There are two switches switch row coloring on and off:

• \hiderowcolors - hide the coloring of rows from this point on
• \showrowcolors - show the coloring of rows from this point on

Colors of individual cells

LaTeX code	PDF result
\documentclass{article} \usepackage[table]{xcolor} \begin{document} \rowcolors{2}{white}{lightgray} \begin{tabular}{lcr} \hline Column A&Column B&Column C\\ \hline Category 1&High&100.00\\ Category 1&High&95.00\\ Category 2&Low&80.50\\ Category 3&Low&82.00\\ \hline \end{tabular} \end{document}

Customizations

The tabularx package

The width of regular tables is determined by the table content. For many tables, this is sufficient. However, when there are many columns and/or large amounts of content, the tables can extend beyond the edges of the page.

The tabularx package (which as a package must be loaded in the preamble) extends the functionality of table creation to allow you to indicate the total width of the table. This new environment, builds on the regular tabular environment. To enable content to fit within a fixed width table, the tabularx introduces a new table spec (X) that indicates that the width of the column is to stretched to allow the table to be the specified width.

The width of the table is defined by an optional length argument to the tabularx environment.

The X column specifier is replaced by a p{} and the width is worked out automatically. If multiple X column specifiers are supplied, then the stretched space will be evenly distributed between all of these columns. Hence, the tabularx environment also makes a simple way to create a table with equal width columns irrespective of their content.

LaTeX code	PDF result
\documentclass{article} \usepackage{tabularx} \begin{document} \begin{tabularx}{\textwidth}{lXX} \hline Column A&Column B&Column C\\ \hline Category 1&High&100.00\\ Category 2&High&80.50\\ \hline \end{tabularx} \end{document}

In order to alter the justification within a stretched column, you can use the \newcolumntype{name}{format} control sequence (in the array package), where name is a single letter name for a new column specifier and format provides the format of this new specifier.

In the following example, the second and third columns are stretched to make the table equal to 90% of the width of a regular line of text. The second column is center justified and the third column is right justified.

LaTeX code
\documentclass{article} \usepackage{tabularx} \usepackage{array} \begin{document} \newcolumntype{C}{>{\centering\arraybackslash}X}% \newcolumntype{R}{>{\raggedleft\arraybackslash}X}% \begin{tabularx}{0.9\textwidth}{lCR} \hline Column A&Column B&Column C\\ \hline Category 1&High&100.00\\ Category 2&High&80.50\\ \hline \end{tabularx} \end{document}
PDF result

In the above example, the second and third columns have equal widths. However, we can modify the definition of a new column specifier to include an argument that determines the fraction of total stretched width for each of the new columns. When doing so, the fractions used must add up to the total number of stretched columns (2 in the following example).

LaTeX code
\documentclass{article} \usepackage{tabularx} \usepackage{array} \begin{document} \newcolumntype{C}[1]{>{\hsize=#1\hsize\centering\arraybackslash}X}% \newcolumntype{R}[1]{>{\hsize=#1\hsize\raggedleft\arraybackslash}X}% \begin{tabularx}{0.9\textwidth}{|l|C{0.5}|R{1.5}|} \hline Column A&Column B&Column C\\ \hline Category 1&High&100.00\\ Category 2&High&80.50\\ \hline \end{tabularx} \end{document}
PDF result

The tabulary environment

The tabulary environment works similar to the tabularx package, except that it is capable of generating appropriate column widths so as to achieve equal row heights. Moreover, unlike the tabularx environment, the optional table width argument is taken as a maximum (rather than a fixed setting). This means that tables will be created to a maximum width, yet can be narrower if there is little content.

LaTeX code	PDF result
\documentclass{article} \usepackage{tabulary} \begin{document} \begin{tabulary}{0.7\textwidth}{JCR} \hline Category&Temperature&Response\\ \hline 1&High and sometimes low&100.00\\ 2&High&80.50\\ \hline \end{tabulary} \end{document}

The tabu environment

The tabu package provides the tabu environment which works similar to the tabularx environment. As well as allowing stretchy columns for fixed table widths, the tabu environment handles multi-page tables and footnotes.

Multi-page tables

When splitting across pages, different tables and headers can be defined for the last and first pages respectively. This allows for running headers and footers and is achieved via the following switches.

LaTeX code
\documentclass{article} \usepackage{longtable} \begin{document} \begin{longtable}{lcr} \hline Category&Temperature&Response\\ \hline \endfirsthead \multicolumn{3}{r}{\tablename~\thetable{} -- continued}\\ \hline Category&Temperature&Response\\ \hline \endhead \hline \multicolumn{3}{r}{continued on next page}\\ \hline \endfoot \hline \endlastfoot 1&High&100.00\\ 2&High&80.50\\ 1&High&95.00\\ 2&High&83.00\\ 1&Medium&120.00\\ 2&Medium&90.50\\ 1&Medium&130.50\\ 2&Medium&88.50\\ 1&Low&200.00\\ 2&Low&180.00\\ 1&Low&220.00\\ 2&Low&170.00\\ \end{longtable} \end{document}
PDF result

The booktabs package

The booktabs package provides numerous additional control sequences and switches to use in the various table environments to help in the production of more professional looking tables. The following table provides a summary of those additional control sequences.

LaTeX code	PDF result
\documentclass{article} \usepackage{tabulary} \begin{document} \usepackage{booktabs} \begin{document} \begin{tabular}{lcr} \toprule Category&Temperature&Response\\ \midrule 1&High&100.00\\ 2&High&80.50\\ \bottomrule \end{tabular} \end{document}

Floating environments

Floats are ideal containers for content such as figures or tables and indeed the two most common float environments are:

• figure
• table

Floats take on the general form of:

  \begin{float}[placement specifier]
  ...
  \end{float}

The placement specifier is only a preference and therefore may be ignored if the preferred placement violates the typical page and paragraph layout rules. For example, a float would not be placed in a place in text that would result in a paragraph being broken in half.

As this is a preference list, multiple placement values can be specified and LaTeX will go through each of the placements in order in an attempt to find a float placement that meets your highest preference whilst still maintaining document flow.

Captions

The full caption, including the label (Table or Figure) and numbering will be placed within the float in the location that the \caption{} control sequence appears relative to the rest of the content. For example, if \caption{} appears at the start of the floating environment, then the caption will appear at the top of the float (above the content), if \caption{} is at the end of the floating environment, then the caption will be underneath the content.

The optional parameter to the \caption[]{} control sequence specifies a shorter caption. This shorter caption (if provided) is used when constructing a list of figures or tables.

Whilst the caption will be centered within the floating environment, the content will be left justified. Hence, it is common wrap the content within a center environment.

Floating figures

 \documentclass{article}
 ...
 \usepackage{graphicx}
 \begin{document}
 ...
 \begin{figure}[htbp]
 \includegraphics{images/ws9.2aQ1.1.png}\\
 \caption{Design schematic of bla bla}
 \end{figure}
 ...
 \end{document}
  

Notice in the example above, that the figure caption is centered whereas the graphic is not. We will address this in the next example.

Force the floating figure to be placed at the bottom (!b) of the page (next in this case). and center the graphic within this float. Again, I have included a partial code snippet, just displaying the syntax relevant for the floating figure.

 \documentclass{article}
 ...
 \usepackage{graphicx}
 \begin{document}
 ...
 \begin{figure}[!b]
 \begin{center}
 \includegraphics[width=0.5\\linewidth]{images/ws9.2aQ1.1.png}\\
 \end{center}
 \caption{Design schematic of bla bla}
 \end{figure}
 ...
 \end{document}
  

List of figures and tables

 \documentclass{article}
 ...
 \usepackage{graphicx}
 \usepackage{booktabs}
 \begin{document}
 ...
 \begin{table}[htbp]
 \begin{center}
 \caption{Design schematic of bla bla}
 \begin{tabular}{lcr}
 \toprule
 Category&Temperature&Response\\
 \midrule
 1&High&100.00\\
 2&High&80.50\\
 \bottomrule
 \end{tabular}
 \end{center}
 \end{table}
 ...
 \begin{figure}[!b]
 \begin{center}
 \includegraphics[width=0.5\\linewidth]{images/ws9.2aQ1.1.png}\\
 \end{center}
 \caption{Temperatures and responses within each category}
 \end{figure}
 ...
 \end{document}
  

Referencing

As the source document is being processed, the value of the counter for the element to which the label is attached, as well as the page number are stored in an axillary file. The counter values and page numbers can then be referenced from another point in the document. That is, they allow elements to be referred to.

The following table documents the most important control sequences for referencing. Each of these take a common compulsory parameter - a unique marker or identifier. The marker can be any string of characters, yet it many find it useful to begin the string with a prefix that represents the sort of element being referenced ( such as sec: for section, fig: for figure etc).

Examples

 \documentclass{article}
 ...
 \usepackage{graphicx}
 \usepackage{booktabs}
 \begin{document}
 \section{Introduction}\label{sec:introduction}
 This is some text that refers to table~\ref{tab:schematic}
 \begin{table}[htbp]
 \begin{center}
 \caption[Design schematic of seasonal experiment]{Design schematic of seasonal experiment}
 \label{tab:schematic}
 \begin{tabular}{lcr}
 \toprule
 Category&Temperature&Response\\
 \midrule
 1&High&100.00\\
 2&High&80.50\\
 \bottomrule
 \end{tabular}
 \end{center}
 \end{table}
 \subsection{Subheading}
 Here is some more text.  This sentence refers to section~\ref{sec:introduction} on
 page~\pageref{sec:introduction}
 \end{document}
  

*.aux file	PDF file
... \newlabel{sec:introduction}{{1}{1}} ... \newlabel{tab:schematic}{{1}{1}} ... The first {1} is the value of the element counter. The second {1} is the page number.

Footnotes

Footnotes are a convenient way to provide extra information or clarification without compromising conciseness or derailing the progression of ideas. Typically, subscript numbers are placed in the main text to indicate a place where a footnote is required and footnotes (the additional information) are set in a smaller font at the bottom of the page.

In LaTeX, footnotes are automatically handled via the \footnote{} control sequence. The single compulsory parameter is the text to place in the footnote at the bottom of the page.

LaTeX code	PDF result
\documentclass{article} \begin{document} \begin{document} There is a counter associated with footnotes and the footnote mark number increments throughout the document\footnote{footnotes can be customized to allow the footnote marker number resets each page.} \end{document}

Bibliographies

In academic writing it is important to cite the original source of information and ideas. Not only does this provide due credit to the author(s) of those data and ideas, it also allows the reader the opportunity to independently evaluate the quality and context of the information and data.

Whilst it is possible to manually enter, format and manage each of the cited works in your LaTeX source document as if it were any other text, different journals and audiences require different formatting styles for both in text citations as well as the list of references at the end of the document. Hence, altering the styles to accommodate different audiences can be time consuming and error prone. Moreover, major edits of the main text body then require careful scrutiny in order to ensure all in-text citations are correctly formatted (i.e. there are often rules about the order of multiple references grouped together, some styles dictate different formats for the first time a piece of work is cited in the document compared to subsequent citations) and that in-text citations match up with the reference list.

In LaTeX, bibliographies are handled by an external application, BibTeX, which is included in most TeX distributions. Along with a bibliography rendering engine, BibTeX defines a flat-text bibliography database (*.bib) for the storage of references.

BibTeX database

In keeping with the simple plain text nature of LaTeX source files, BibTeX files (*.bib) are also simple plain text. The general structure of BibTeX entries is exemplified as follows (two examples, one of an article and the other of a book):

  @article{Bolker-2008-127,
  author = {Bolker, B. M. and Brooks, M. E. and Clark, C. J. and Geange, S. W. and Poulsen, 
  J. R. and Stevens, H. H. and White, J. S.},
  journal = {Trends in Ecology and Evolution},
  number = {3},
  pages = {127-135},
  title = {Generalized linear mixed models: a practical guide for ecology and evolution},
  volume = {24},
  year = {2008}
  }

  @book{goossens93,
  author    = "Michel Goossens and Frank Mittlebach and Alexander Samarin",
  title     = "The LaTeX Companion",
  year      = "1993",
  publisher = "Addison-Wesley",
  address   = "Reading, Massachusetts"
  }

• Entries begin with a declaration of the type of reference (e.g. article, book etc).
• The main body of an entry comprises a number of reference attributes (such as the authors, title, year published etc), each represented as a name = value pair and separated by commas
• The first attribute is a unique identifier for the entry. Whilst this can be any unique combination of characters, experienced users tend to settle on a format that reflects the actual reference (such as a combination of first author and year/page number etc)
• The value must be enclosed in either double quotation marks ("") or curly braces ({})
• Depending on the reference type, some attributes are compulsory and others are optional and the order of the attributes is unimportant.
• Accented and other special characters are supported as in LaTeX.
• Authors values can be specified as either surname, forename or forename surname
• Multiple authors are separated by an and

  @article{authorYear,
  author    = {},
  title     = {},
  journal   = {},
  %volume   = {},
  %number   = {},
  %pages    = {},
  year      = {XXXX},
  %month    = {},
  %note     = {},
  }  

  @book{authorYear,
  author    = {},
  title     = {},
  publisher = {},
  %volume   = {},
  %number   = {},
  %series   = {},
  %address  = {},
  %edition  = {},
  year      = {XXXX},
  %month    = {},
  %note     = {},
  }

  @incollection{authorYear,
  author    = {},
  title     = {},
  booktitle = {},
  publisher = {},
  %editor   = {},
  %volume   = {},
  %number   = {},
  %series   = {},
  %type     = {},
  %chapter  = {},
  %pages    = {},
  %address  = {},
  %edition  = {},
  year      = {XXXX},
  %month    = {},
  %note     = {},
  }

  @inproceedings{authorYear,
  author        = {},
  title         = {},
  booktitle     = {},
  %editor       = {},
  %volume       = {},
  %number       = {},
  %series       = {},
  %pages        = {},
  %address      = {},
  %organization = {},
  %publisher    = {},
  year          = {XXXX},
  %month        = {},
  %note         = {},
  }

  @manual{authorYear,
  %author        = {},
  title         = {},
  %organization = {},
  %address      = {},
  %edition     = {},
  %year          = {XXXX},
  %month        = {},
  %note         = {},
  }

  @techreport{authorYear,
  author      = {},
  title       = {},
  institution = {},
  %type       = {},
  %number     = {},
  %address    = {},
  year        = {XXXX},
  %month      = {},
  %note       = {},
  }

  @mastersthesis{authorYear,
  author      = {},
  title       = {},
  school      = {},
  %type       = {},
  %address    = {},
  year        = {XXXX},
  %month      = {},
  %note       = {},
  }

  @phdthesis{authorYear,
  author       = {},
  title        = {},
  school       = {},
  %type        = {},
  %address     = {},
  howpublished = {},
  year         = {XXXX},
  %month       = {},
  %note        = {},
  }

  @proceedings{authorYear,
  title         = {},
  school        = {},
  %editor       = {},
  %volume       = {},
  %number       = {},
  %series       = {},
  %organization = {},
  %publisher    = {},
  %address      = {},
  year          = {XXXX},
  %month        = {},
  %note         = {},
  }

  @inbook{authorYear,
  title         = {},
  author        = {},
  school        = {},
  chapter       = {},
  pages         = {},
  publisher     = {},
  %editor       = {},
  %volume       = {},
  %number       = {},
  %series       = {},
  %type         = {},
  %address      = {},
  %edition      = {},
  year          = {XXXX},
  %month        = {},
  %note         = {},
  }

  @misc{authorYear,
  %title        = {},
  %author       = {},
  %howpublished = {},
  school        = {},
  chapter       = {},
  pages         = {},
  publisher     = {},
  year          = {XXXX},
  %month        = {},
  %note         = {},
  }

BibTeX

In addition to these citation markers, the source document should contain two additional control sequences at the end of the document (yet prior to the \end{document} marker):

• \bibliographystyle{} - this indicates the style of the bibliography. We return to this later.
• \bibliography{} - this points to one or more BibTeX database files. It also serves to indicate where the list of references should be placed in the final document.

  \documentclass{article}
  \begin{document}
  ... a easily digestible treatment of generalized linear 
  mixed effects models \cite{Bolker-2008-127}.
  \bibliographystyle{plain}
  \bibliography{refs.bib}
  \end{document}						  

  @article{Bolker-2008-127,
  author = {Bolker, B. M. and Brooks, M. E. and Clark, C. J. and Geange, S. W. and Poulsen, 
  J. R. and Stevens, H. H. and White, J. S.},
  journal = {Trends in Ecology and Evolution},
  number = {3},
  pages = {127-135},
  title = {Generalized linear mixed models: a practical guide for ecology and evolution},
  volume = {24},
  year = {2008}
  }

  @book{goossens93,
  author    = "Michel Goossens and Frank Mittlebach and Alexander Samarin",
  title     = "The LaTeX Companion",
  year      = "1993",
  publisher = "Addison-Wesley",
  address   = "Reading, Massachusetts"
  }

1. Firstly, as the LaTeX engine processes the source document and when it encounters one of the citation control sequences (see below) an entry is written to the *.aux axillary file.

   xelatex tut17.1S13.1a.tex  
     

   LaTeX axillary file (for example tut17.1S13.1a.aux)	PDF output
   \relax \citation{Bolker-2008-127} \bibstyle{plain} \bibdata{refs.bib}

   At this stage (prior to running BibTeX, LaTeX is unable to resolve the citation and thus inserts a ?.
2. When BibTex is then run on this *.aux file:

   bibtex tut17.1S13.1a.aux  
     

   BibTeX library file (for example tut17.1S13.1a.bbl)
   \begin{thebibliography}{1} \bibitem{Bolker-2008-127} B.~M. Bolker, M.~E. Brooks, C.~J. Clark, S.~W. Geange, J.~R. Poulsen, H.~H. Stevens, and J.~S. White. \newblock Generalized linear mixed models: a practical guide for ecology and evolution. \newblock {\em Trends in Ecology and Evolution}, 24(3):127--135, 2008. \end{thebibliography}

   Essentially, BibTeX determines which of the references in the *.bib file are required (based on what entries are in the *.aux file, and then formats the references according to the nominated bibliography style. This information is collected together into an environment and awaits an additional LaTeX run when it will be incorporated into the document at runtime.

   BibTeX also modifies the *.aux file. It adds a \bibcite{}{} control sequence for each of the cited references. These control sequences indicate the format of the in-text citation.

3. When LaTeX is run for a second time, the *.bbl file is parsed during the source document preamble, and therefore, the references are now available for inclusion.

   xelatex tut17.1S13.1a.tex  
     

   
4. Finally, we run LaTeX a third time to ensure that all the citation information has been included in the the document.

   xelatex tut17.1S13.1a.tex  
     

   

Bibliography (list of references) styles

There is not a single referencing format. Different disciplines often require very different styles. Even within disciplines, formats can vary subtly or even substantially between journals. For example, some publications require that the list of references be ordered alphabetically by senior order, whilst others are sorted according to the order in which the works are cited in the main text.

The formatting of the bibliography (list of references) can be controlled by the \bibliographystyle{} control sequence. This takes a single parameter, the name (including full path if not one of the pre-installed styles).

• LaTeX and BibTeX style files for biologists
• Bibliography style files for selected ecology/biology journals

 \documentclass{article}
 \begin{document}
 ... a easily digestible treatment of generalized linear 
 mixed effects models \cite{goossens93,Bolker-2008-127}.
 \bibliographystyle{apalike}
 \bibliography{References/refs.bib}
 \end{document}  
  

In addition to the bibliography style files that come with modern TeX distributions, it is possible to modify these to create new styles that meet your needs. Moreover, many publishers also make bibliography style files available to authors support their referencing requirements. These bibliography style files can either be placed in the same directory as the original *.tex source document, or, if placed in another directory, the \bibliographystyle style parameter must include the full path name.

The next section introduces a package for supporting even further bibliography styles.

In-text citations

The natbib package provides a great flexibility of in-text citation styles. In order to use the following in-text citation styles, you must first make two alterations to the source document:

• Use the package in the source preamble:

    \usepackage[options]{natbib}					
  

  Options	Description
  authoryear	Author/year citation style (default for natbib)
  numbers	Numeric citation style (default for non natbib)
  super	Superscripted numeric citation style
  colon	Multiple citations separated by colons (default for natbib)
  comma	Multiple citations separated by commas
  sort	Multiple citations are ordered according to their order in the reference section.
  sort&compress	As for sort, also compressing multiple citations
  longnamesfirst	The first occurrence a multi-author citation including expanded author list, subsequent occurrences using an abbreviated style (e.g. et. al.)
  round	Parentheses () (default for natbib)
  square	Square brackets []
  curly	Curly braces {}
  angle	Angle brackets <>

• Alter the bibliography style to one of the natbib compatible styles (see table below):

    \bibliographystyle{style}					
  

  Styles	Description
  plainnat	Natbib compatible version of the plain bibliography style
  abbrvnat	Natbib compatible version of the abbrv bibliography style
  unsrtnat	Natbib compatible version of the unsrt bibliography style

 \documentclass{article}
 \usepackage[round]{natbib}
 \begin{document}
 ... a easily digestible treatment of generalized linear 
 mixed effects models \cite{Bolker-2008-127}.
 Multiple references will appear in the order that they are provided \citep{Bolker-2008-127,goossens93}, 
 unless the sort option is used.
 \bibliographystyle{apalike}
 \bibliography{References/refs.bib}
 \end{document}  
  

Mathematical formulae

As mentioned in the introduction to this tutorial, one of the greatest motivating factors in the development of TeX, was the need to produce elegant mathematical equations. Testament to the success of this component is the fact that this mathematical engine has become the benchmark by which all other equation generators are compared. Indeed, many other applications adopt the LaTeX math engine for equations.

LaTeX typesets mathematical notation differently (has different rules etc) than regular text. Therefore all mathematical notation must occur within dedicated math environments.

Mathematical environments

• inline - surrounded by regular text without line. Typically, inline equations are just for very simple equations that lack complex symbols and structures that do not disrupt the usual spacing of lines of text.
• displayed - separated from the main text.

\(..\)

$..$

\[..\]

$$..$$

LaTeX code

PDF result

\documentclass{article} \begin{document} The formula, $y=mx+c$, is displayed inline. Some symbols and equations (such as $\sum{x}$ or $\frac{1}{2}$) are rescaled to prevent disruptions to the regular line spacing. For more voluminous equations (such as $\sum{\\frac{(\mu - \bar{x})^2}{n-1}}$), some line spacing disruptions are unavoidable. Math should then be displayed in displayed mode. $$\sum{\frac{(\mu - \bar{x})^2}{n-1}}$$ \end{document}

There are some additional considerations while in math mode (the mode used to typeset mathematical equations either inline or displayed) compared to regular text mode:

• Each letter is considered to represent a separate variable and is therefore italicized. In order to preserve the regular text style of words within formulae, the word must be used as an argument to a \text{} control sequence.
• Most spaces (including those between words as math mode does not recognize words) are ignored in math mode. Additional space within formulae can be defined with the \quad and \qquad control sequences (see below)
• Blank lines are not permitted within math mode

Symbols

 + - = ! / ( ) [ ] < > | ' :
  

• symbols-a4.pdf - a PDF document
• Detetify - LaTeX symbol classifier - an ingenious web tool that provides a list of candidate symbols based on a scribbled symbol you have drawn on its canvas.

Operators

Greek letters

Delimeters

Set and logic notation

Powers, indicies, and roots

Sums and integrals

$\sum x$.

$\sum_{i=1}^{100} x$.

$\sum\limits_{i=1}^{100} x$.

$\int_{0}^{\infty} e^{-x} dx$.

$\int\limits_{0}^{\infty} e^{-x} dx$.

Fractions

The fraction was $4/5$.

The fraction was $^4/_5$.

$$\frac{x}{n-1}$$

$$\frac{\sum{(x-\bar{x})^2}}{n-1}$$

Bracket and brace sizing

• automatically - using the \left, \right and middle temporary command switches. When placed directly before one of the delimiters, it attempts to scales the delimiter according to the size of the adjoining content.

  Example math code	Result
  $$\left(\frac{x_2}{n-1}\right)$$	$$\left(\frac{x_2}{n-1}\right)$$
  $$\left\{\frac{x^2}{y^3}\right\}$$	$$\left\{\frac{x^2}{y^3}\right\}$$

• manually - using the \big, \Big, \bigg, \Bigg modifier commands that define increasingly larger sizes that are particularly useful for nested brackets/braces.

  Example math code	Result
  $$\Big((x-\bar{x})^2 + (y-\bar{y})^2\Big)$$	$$\Big((x-\bar{x})^2 + (y-\bar{y})^2\Big)$$

Mixing regular text and math

As mentioned previously, all letters are italicized and spaces are ignored. Nevertheless, it is possible to force the math engine to respect some text mode formatting via the \text{} control sequence. In addition, the other text formatting control sequences (\textrm{}, \textit{}, \textbf{} etc) can also be used.

$$response = constant + \beta \times IV1$$

$$\text{response} = \text{constant} + \beta\times \text{IV1}$$

$$\text{response} = \text{constant} + \beta\times \textbf{IV1}$$

Formatting math font

Math font control sequence	Sample	Use
\mathnormal{}		Typical mathematical notation (and default)
\mathrm{}		Appropriate for units of measurement or single word functions
\mathit{}
\mathbf{}		Vector notation
\mathsf{}
\mathtt{}		Monospace font to represent code
\mathcal{}		Calligraphy font to represent schemes and sheaves in number theory and algebraic geometry
\mathfrak{}		Fraktur font to represent lie algebras
\mathbb{}		Blackboard bold font to represent sets

Accents in math mode

$a'$ $a''$ $a'''$ $a''''$

$\underline{x}$ $\bar{x}$

$\grave{x}$ $\acute{x}$

$\dot{x}$ $\ddot{x}$

$\not{x}$ $\mathring{x}$

$\overrightarrow{XY}$ $\overleftarrow{XY}$

$\overline{x}$ $\vec{x}$

$\check{x}$ $\breve{x}$

$\hat{x}$ $\widehat{XY}$

$\tilde{x}$ $\widetilde{XY}$

Horizontal spacing

$y=bx+a\quad\epsilon\sim{}N(0,1)$

$y=bx+a\qquad\epsilon\sim{}N(0,1)$

$y=bx+a\,\epsilon\sim{}N(0,1)$

$y=bx+a\:\epsilon\sim{}N(0,1)$

$y=bx+a\;\epsilon\sim{}N(0,1)$

$y=bx+a\!\epsilon\sim{}N(0,1)$

Further reading

• LaTeX wikibook
• ctable documentation (pdf)