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     1 LaTeX
       
     2 =====
       
     3 
       
     4 Introduction
       
     5 ------------
       
     6 LaTeX is a typesetting program used to produce excellently typeset documents. It is extensively used for producing high quality scientific and mathematical documents. It may also be used for producing other kinds of documents, ranging from simple one page articles or letters 
       
     7 
       
     8 
       
     9 TeX & LaTeX
       
    10 ~~~~~~~~~~~
       
    11 
       
    12 TeX
       
    13 +++
       
    14 
       
    15 TeX is a typesetting system designed by Donald Knuth, the renowned Computer Scientist and Emeritus professor at Stanford University. Typesetting is placing text onto a page with all the style formatting defined, so that content looks as intended. 
       
    16 
       
    17 It was designed with two goals in mind-
       
    18 
       
    19 1. To allow anybody to produce high-quality books using a reasonable amount of effort. 
       
    20 2. To provide a system that would give the exact same results on all computers, now and in the future
       
    21 
       
    22 TeX is well known for it's stability and portability. 
       
    23 
       
    24 TeX is pronounced as "tech".
       
    25 
       
    26 The current version of TeX is 3.1415926 and is converging to π.
       
    27 
       
    28 LaTeX
       
    29 +++++
       
    30 
       
    31 LaTeX was originally written by Leslie Lamport in the early 1980s. It is an extension of TeX, consisting of TeX macros and a program to parse the LaTeX files. It is easier to use than TeX itself, at the same time producing the same quality of output. 
       
    32 
       
    33 LaTeX is pronounced either as "Lah-tech" or "Lay-tech"
       
    34 
       
    35 WYSIWG vs. WYSIWM
       
    36 ~~~~~~~~~~~~~~~~~
       
    37 
       
    38 WYSIWG is an acronym for "What You See Is What You Get". Word processors, are typically WYSIWG tools. LaTeX, TeX or other TeX based tools are not. They are typesetting or text formatting or document description programs. They can be called WYSIWM or "What You See Is What you Mean" systems, since you give a description of how things look, and LaTeX typesets the document for you.
       
    39 
       
    40 Here are a few reasons, why you should use LaTeX -
       
    41 
       
    42   * LaTeX produces documents with excellent visual quality, especially mathematical and scientific documents. 
       
    43   * It does the typesetting to you. Typically, when one works with a word-processor, the user is doing the text formatting or typesetting along with typing out the content. LaTeX allows the user to concentrate on the content leaving aside the typesetting to LaTeX. 
       
    44   * It is light on your resources as compared to most of the word processors available today. 
       
    45   * It is well known for it's stability and for it's virtually bug free code base. 
       
    46   * It encourages users to structure documents by meaning rather than appearance, thereby helping produce well structured documents. 
       
    47   * It uses plain text files as input, which have a lot of well known advantages over binary files. To state a few, they can be opened with any editor on any operating system, they are smaller in size compared to the binaries, can be version controlled and can be processed using widely used text processing utilities. 
       
    48   * The output can be generated in more than one formats.
       
    49   * It is free software (free as in freedom) and gratis too.
       
    50   * It is widely used.
       
    51 
       
    52 Hello World
       
    53 ~~~~~~~~~~~
       
    54 
       
    55 OK, let's get started with our first LaTeX document. Open up your favorite editor and type in the following code. 
       
    56 
       
    57 ::
       
    58 
       
    59   %hello.tex - First LaTeX document
       
    60   \documentclass{article}
       
    61 
       
    62   \begin{document}
       
    63     Hello, World!
       
    64   \end{document}
       
    65 
       
    66 Save the file as ``hello.tex`` and open up a terminal to compile your ``tex`` file to get the output in a ``pdf`` format. 
       
    67 
       
    68 Compiling & Output
       
    69 ++++++++++++++++++
       
    70 
       
    71 ::
       
    72 
       
    73   $pdflatex hello.tex
       
    74 
       
    75   Output written on hello.pdf (1 page, 5733 bytes).
       
    76   Transcript written on hello.log.
       
    77 
       
    78 Open the ``hello.pdf`` to see the output as shown. 
       
    79 
       
    80 .. image:: examples/hello.jpg
       
    81 
       
    82 Note: The command ``latex`` is often used to get the ``dvi`` output. But, throughout this course, we shall use pdflatex to compile our documents. 
       
    83 
       
    84 A peek at the source
       
    85 ++++++++++++++++++++
       
    86 
       
    87 ``%hello.tex - First LaTeX document``
       
    88 
       
    89   This line is a comment. LaTeX ignores this line and it is meant only for the human readers. LaTeX ignores anything after a ``%`` symbol to the end of the line. 
       
    90 
       
    91 ``\documentclass{article}``
       
    92 
       
    93   This line is a command and sets the ``documentclass`` of the document to ``article``. LaTeX has other classes like ``report``, ``book``, ``letter``, etc. The typesetting of the document varies depending on the ``documentclass`` of the document. 
       
    94 
       
    95 
       
    96 ``\begin{document}``
       
    97 
       
    98   This line informs LaTeX that this is the beginning of the content of the document. 
       
    99 
       
   100 ``Hello, World!``
       
   101 
       
   102   This is the actual text displayed in the document. 
       
   103 
       
   104 ``\end{document}``
       
   105 
       
   106   This line tells LaTeX that the document is complete and LaTeX will simply ignore anything written after this line.
       
   107 
       
   108 Where do we want to go
       
   109 ~~~~~~~~~~~~~~~~~~~~~~
       
   110 
       
   111 During the course of this session we will learn how to do various things in LaTeX and try to produce the sample document provided. 
       
   112 
       
   113 Some Basics
       
   114 ~~~~~~~~~~~
       
   115 Before we get started with creating the document, let's try to understand a few things that would be useful during the course of this session. 
       
   116 
       
   117 Spaces
       
   118 ++++++
       
   119 
       
   120 LaTeX treats multiple empty spaces (or lines) as a single space (or line). An empty line between two lines of text is considered as a change of paragraphs. 
       
   121 
       
   122 Line & Page Breaks
       
   123 ++++++++++++++++++
       
   124 
       
   125 LaTeX usually does the job of breaking up your content into lines and pages, and does it well. But under some circumstances, you might want to instruct LaTeX to break line or start a new page at a particular point. 
       
   126 
       
   127 ``\\`` or ``\newline`` command is used to create a new line at the point where the command is issued. 
       
   128 Appending ``*`` to ``\\``,  instructs LaTeX to create a new line, without creating a new page at that point. 
       
   129 
       
   130 Paragraphs
       
   131 ++++++++++
       
   132 
       
   133 As already mentioned, LaTeX considers an empty line between two lines of text as a new paragraph. ``\par`` command may also be used to start a newline. It is equivalent to the blank line. 
       
   134 
       
   135 By default LaTeX indents new paragraphs. If you do not wish to have the paragraph indented, you can use the ``\nointend`` command at the beginning of the paragraph. 
       
   136 
       
   137 Special Characters
       
   138 ++++++++++++++++++
       
   139 
       
   140 LaTeX associates special meaning to the  characters ``~ # $ % ^ & _ { } \``. 
       
   141 
       
   142 To have these characters in the text of your document, you need to prefix a backslash to them. ``\~ \# \% \$ \^ \& \_ \{ \} \textbackslash``
       
   143 
       
   144 
       
   145 Commands
       
   146 ++++++++
       
   147 
       
   148 * All LaTeX commands start with a backslash ``\``.
       
   149 * Like the commands in Linux, they are case sensitive.
       
   150 * They usually have a backslash followed by a consisting of letters only. Any character other than letters, like space, numbers or special characters terminate the command. 
       
   151 * The commands for producing special characters in the text, is an exception. They contain a backslash followed by a single special character.
       
   152 * Commands may have parameters, which are supplied to them by enclosing them in curly braces ``{ }``.
       
   153 * They may also have a few optional parameters which are added after the name in square brackets ``[ ]``.
       
   154 
       
   155 
       
   156 Environments
       
   157 ++++++++++++
       
   158 
       
   159 Environments are very similar to the commands, except that they effect larger parts of the document. For example, we used the ``document`` environment in our first LaTeX document. 
       
   160 
       
   161 * They begin with a ``\begin`` and end with a ``\end``
       
   162 * In general environments can be nested within each other. 
       
   163 
       
   164 Some Structural Elements
       
   165 ------------------------
       
   166 
       
   167 ``\documentclass``
       
   168 ~~~~~~~~~~~~~~~~~~
       
   169 As already stated, the ``documentclass`` command tells LaTeX, the type of the document that you intend to create. Each class has a few differences in how the content of the document is typeset. We presently have it set to the article class. Let us try changing it to the report class. 
       
   170 
       
   171 Note that the top matter of the document appears in a different page for the report class. 
       
   172 
       
   173 Some of the LaTeX classes that you may want to use are, article, proc, report, book, slides, letter. 
       
   174 
       
   175 The ``documentclass`` command also accepts a few optional parameters. For example::
       
   176   \documentclass[12pt,a4paper,oneside,draft]{report}
       
   177 
       
   178 ``12pt`` specifies the size of the main font in the document. The relative sizes of the various fonts is maintained, when the font size is changed. If no size is specified, ``10pt`` is assumed by default. 
       
   179 
       
   180 ``a4paper`` specifies the size of the paper to be used for the document. 
       
   181 
       
   182 ``oneside`` specifies that the document will be printed only on one side of the paper. The ``article`` and ``report`` classes are ``oneside`` by default and the ``book`` class is ``twoside``.
       
   183 
       
   184 ``draft`` marks the hyphenation and justification problems in the document with a small square in the right hand margin of the document, so that they can be easily spotted. 
       
   185 
       
   186 Note: Everything written in between the ``\documentclass`` command and the ``\begin{document}`` command is called the Preamble. 
       
   187 
       
   188 
       
   189 Parts, Chapters and Sections
       
   190 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
       
   191 
       
   192 Often documents are divided into various parts, chapters, sections and subsections. LaTeX provides an intuitive mechanism to include this in your documents. It has various commands like ``part``, ``chapter``, ``section``, ``subsection``, ``subsubsection``, ``paragraph`` and ``subparagraph``. Note that all these commands are not available in all the document classes. The ``chapter`` command is available only in books and reports. Also, the ``letter`` document class does not have any of these commands. 
       
   193 
       
   194 Let us now give our document some structure, using these commands. 
       
   195 
       
   196 Note that you do not need to provide any numbers to the commands. LaTeX automatically takes care of the numbering. 
       
   197 Also, you do not need to enclose the text of a block within ``\begin`` and ``\end`` commands. LaTeX starts a new block each time it finds a sectioning command. 
       
   198 ::
       
   199 
       
   200   \section[Short Title]{This is a very long title and the Short Title will appear in the Table of Contents.}
       
   201 
       
   202 
       
   203 Section Numbering
       
   204 +++++++++++++++++
       
   205 
       
   206 As already, you don't need to explicitly do any numbering in LaTeX. Parts are numbered using roman numerals; Chapters and sections are numbered using decimal numbers. When the table of contents is inserted into a document, all the numbered headings automatically appear in it.
       
   207 
       
   208 By default LaTeX has numbering up 2 levels, i.e, the parts, chapters, sections and subsections are numbered. You can change this by setting the ``secnumdepth`` counter using the ``\setcounter`` command. The following command removes numbering of the subsections. Only parts, chapters and sections are numbered. 
       
   209 ::
       
   210 
       
   211   \setcounter{secnumdepth}{1}
       
   212 
       
   213 A sectioning command appended with an asterisk gives an unnumbered heading that is not included in the table of contents.
       
   214 ::
       
   215 
       
   216   \section*{Introduction}
       
   217 
       
   218 Top Matter
       
   219 ~~~~~~~~~~
       
   220 
       
   221 The information about the document such as it's title, the date, the author(s) information etc, is collectively known as the topmatter. Though there is no command called ``topmatter``, the term topmatter is frequently used in LaTeX documentation. 
       
   222 
       
   223 Let us input the top matter for our document now. 
       
   224 ::
       
   225 
       
   226   \title{LaTeX - A How-to}
       
   227   \author{The FOSSEE Team}
       
   228   \date
       
   229 
       
   230 The  commands ``\title`` and  ``\author`` are self explanatory. 
       
   231 The ``\date`` command automatically puts in today's date into the document. Now let us compile and look at the result. 
       
   232 
       
   233 You would observe that the details do not appear in the document after recompilation. This is because, LaTeX has not been instructed what to do with the top matter information that you have given it. Use the ``\maketitle`` command within the document environment to instruct LaTeX to place the top matter information into the document. 
       
   234 
       
   235 Abstract
       
   236 ~~~~~~~~
       
   237 Lets now place and abstract in the document using the ``abstract`` environment of LaTeX. The abstract appears in the document after the topmatter but before the main body of the document. 
       
   238 ::
       
   239 
       
   240   \begin{abstract}
       
   241   The abstract abstract.
       
   242   \end{abstract}
       
   243 
       
   244 
       
   245 Appendices
       
   246 ~~~~~~~~~~
       
   247 
       
   248 LaTeX allows for separate numbering for appendices. ``\appendix`` command indicates that the sections following are to be included in the appendix. 
       
   249 ::
       
   250 
       
   251   \appendix
       
   252   \chapter{First Appendix}
       
   253 
       
   254 Table of Contents
       
   255 ~~~~~~~~~~~~~~~~~
       
   256 
       
   257 Parts, chapters or sections that have been auto numbered by LaTeX automatically appear in the Table of Contents (ToC). ``\tableofcontents`` command places a the ToC, where the command has been issued. 
       
   258 
       
   259 The counter ``tocdepth`` specifies the depth up to which headings appear in the ToC. It can be set using the ``\setcounter`` command as shown below. 
       
   260 ::
       
   261 
       
   262   \setcounter{tocdepth}{3}
       
   263 
       
   264 Unnumbered sections can be placed in the table of contents using the ``\addcontentsline`` command as shown below.
       
   265 ::
       
   266 
       
   267   \section*{Introduction}
       
   268   \addcontentsline{toc}{section}{Introduction}
       
   269 
       
   270 Note: To get the correct entries in your table of contents, you will need to run one extra compilation, each time. This is because, the entries of the table of contents are collected during each compilation of the document and utilized during the next compilation. 
       
   271 
       
   272 Elementary Text Typesetting
       
   273 ---------------------------
       
   274 
       
   275 Emphasizing
       
   276 ~~~~~~~~~~~
       
   277 
       
   278 *Italic* font is generally used to emphasize text. The ``\emph`` command may be used to achieve this effect in LaTeX.
       
   279 ::
       
   280 
       
   281   This is the \emph{emphasized text}.
       
   282 
       
   283 If the ``\emph`` command is nested within another emphasize command, LaTeX emphasized that text using normal fonts. 
       
   284 ::
       
   285 
       
   286   \emph{Did you wonder what happens when we try \emph{emphasizing text} within \emph{emphasized text}}?
       
   287 
       
   288 *This is emphasized text, and* this is emphasized text with normal font *, within* emphasized text.
       
   289 
       
   290 Quotation Marks
       
   291 ~~~~~~~~~~~~~~~
       
   292 
       
   293 When typing in LaTeX, the double quotation mark ``"`` character shouldn't be used. The grave accent ````` character produces the left quote and the apostrophe ``'`` character produces the right quote. To obtain double quotes they are, each, used twice. 
       
   294 ::
       
   295 
       
   296   `` Here is an example of putting `text' in quotes ''
       
   297 
       
   298 Dashes and Hyphens
       
   299 ~~~~~~~~~~~~~~~~~~
       
   300 
       
   301 LaTeX has four dashes of different lengths. Three of them can be produces with different number of consecutive dashes. The short dashes are used for hyphens, slightly longer ones for number ranges and the longest ones for comments. The fourth one is a mathematical symbol, the minus sign. 
       
   302 ::
       
   303 
       
   304   The names of these dashes are: `-' hyphen, `--' en-dash, `---' em-dash and `$-$' minus sign.
       
   305 
       
   306 The names for these dashes are: ‘‐’ hyphen, ‘–’ en-dash, ‘—’ em-dash and ‘−’ minus sign.
       
   307 
       
   308 Footnotes
       
   309 ~~~~~~~~~
       
   310 
       
   311 With the command::
       
   312 
       
   313   \footnote{footnote text}
       
   314 
       
   315 a footnote is printed at the foot of the current page. Footnotes should always be put after the word or sentence they refer to. Footnotes referring to a sentence or part of it should therefore be put after the comma or period.
       
   316 
       
   317 Note: Look at the ``\marginpar`` command to insert margin notes
       
   318 
       
   319 Flushleft, Flushright, and Center
       
   320 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
       
   321 
       
   322 The environments ``flushleft`` and ``flushright`` generate paragraphs that are either left- or right-aligned. 
       
   323 
       
   324 The ``center`` environment generates centered text.
       
   325 
       
   326 Itemize, Enumerate, and Description
       
   327 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
       
   328 LaTeX has three different environments for producing lists. Itemize, Enumerate and Description allow you to produce lists of various types in LaTeX. 
       
   329 
       
   330 Itemize is used to produce unnumbered lists. The bullets of the list can be easily changed to use any character. Enumerate environment allows you to produce auto-numbered lists. The description environment, allows you to produce a list of definitions. These environments can be nested within each other, easily. 
       
   331 
       
   332 ::
       
   333 
       
   334   \begin{itemize}
       
   335     \item Now we move onto some elementary \emph{Text Typesetting}.
       
   336     \item How do we get \emph{emphasized or italic text}?
       
   337     \item \emph{Did you wonder what happens when we try \emph{emphasizing text} within \emph{emphasized text}}?
       
   338     \item ``Beautiful is better than ugly.''
       
   339   \end{itemize}
       
   340   
       
   341   \begin{description}
       
   342     \item[Description] This list is a description list. 
       
   343     \item[Enumerate] Numbered lists are often useful.
       
   344       \begin{enumerate}
       
   345       \item First
       
   346       \item Second
       
   347       \item Third
       
   348       \item \ldots
       
   349       \end{enumerate}
       
   350     \item[Itemize] The list above this description list is an itemize list.
       
   351   \end{description}
       
   352   
       
   353 Quote, Quotation, and Verse
       
   354 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
       
   355 
       
   356 LaTeX provides a ``quote`` environment that can be used for quoting, highlighting important material, etc. 
       
   357 ::
       
   358 
       
   359   The Zen of Python
       
   360   \begin{quote}
       
   361     The Zen of Python, by Tim Peters
       
   362     
       
   363     Beautiful is better than ugly.
       
   364     Explicit is better than implicit.
       
   365     Simple is better than complex.
       
   366     Complex is better than complicated.
       
   367     Flat is better than nested.
       
   368     Sparse is better than dense.
       
   369     Readability counts.
       
   370     Special cases aren't special enough to break the rules.
       
   371     Although practicality beats purity.
       
   372     Errors should never pass silently.
       
   373     Unless explicitly silenced.
       
   374     In the face of ambiguity, refuse the temptation to guess.
       
   375     There should be one-- and preferably only one --obvious way to do it.
       
   376     Although that way may not be obvious at first unless you're Dutch.
       
   377     Now is better than never.
       
   378     Although never is often better than *right* now.
       
   379     If the implementation is hard to explain, it's a bad idea.
       
   380     If the implementation is easy to explain, it may be a good idea.
       
   381     Namespaces are one honking great idea -- let's do more of those!
       
   382   \end{quote}
       
   383 
       
   384 LaTeX provides two other similar environments, the quotation and the verse environments. 
       
   385 
       
   386 The quotation environment can be used for longer quotes which have several paragraphs, since it indents the first line of each paragraph. 
       
   387 
       
   388 The verse environment may be used to quote verses or poems, since the line breaks are important in quoting them. The lines are separated using ``\\\\`` at the end of a line and an empty line after each verse. 
       
   389 
       
   390 Verbatim
       
   391 ~~~~~~~~
       
   392 The verbatim environment allows us to insert pre-formatted text in a LaTeX document. It is useful for inserting code samples within the document. The verbatim text needs to be enclosed between ``\begin{verbatim}`` and ``\end{verbatim}``. 
       
   393 ::
       
   394 
       
   395   \begin{verbatim}
       
   396   from numpy import *
       
   397   a = linspace(0, 5, 50, endpoint = False)
       
   398   \end{verbatim}
       
   399 
       
   400   from numpy import *
       
   401   a = linspace(0, 5, 50, endpoint = False)
       
   402 
       
   403 To insert verbatim text in-line, the ``\verb`` command can be used. 
       
   404 ::
       
   405   
       
   406  The verb command allows placing \verb|verbatim text| in-line. 
       
   407 
       
   408 The | is just an example of a delimiter character. You can use any character except letters, * or space.
       
   409 
       
   410 Tables, Figures and Captions
       
   411 ----------------------------
       
   412 
       
   413 The ``\tabular`` environment
       
   414 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
       
   415 
       
   416 The ``tabular`` environment allows you to typeset tables in LaTeX. ``\begin{tabular}[pos]{col fmt}`` command can be used to specify the parameters of the table and start creating the table. 
       
   417 
       
   418 The ``pos`` argument specifies the vertical position of the table relative to the baseline of the surrounding text. It can take on the values ``t`` for top, ``b`` for bottom, or ``c`` for center. 
       
   419 
       
   420 
       
   421 The ``col fmt`` argument specifies the formatting of the columns of the table. You need to explicitly specify the formatting for each of the columns in the table. The ``col fmt`` argument can take on the following values. 
       
   422 
       
   423 +---------------+------------------------------------+
       
   424 | ``l``         | left justified column content      |
       
   425 +---------------+------------------------------------+
       
   426 | ``r``         | right justified column content     |
       
   427 +---------------+------------------------------------+
       
   428 | ``c``         | centered column content            |
       
   429 +---------------+------------------------------------+
       
   430 | ``*{n}{col}`` | produces ``n`` columns with the    |
       
   431 |               | ``col`` type of formatting         |
       
   432 |               | ``*{3}{c}`` is the same as {c c c} |
       
   433 +---------------+------------------------------------+
       
   434 | ``|``         | produces a vertical line.          |
       
   435 +---------------+------------------------------------+
       
   436 
       
   437 Now we look at how to input the actual entries of the tables. Each horizontal row in a table is separated by ``\\``. Each column entry of a row is separated by ``&``. 
       
   438 
       
   439 The ``\hline`` command allows you to draw horizontal lines between two rows of the table. But it does not allow you do draw partial lines. ``\cline{a-b}`` draws a horizontal line from column ``a`` to column ``b``.
       
   440 ::
       
   441 
       
   442   \begin{tabular}{|c|c|}
       
   443     \hline
       
   444     \verb+l+ & left justified column content\\ 
       
   445     \hline
       
   446     \verb+r+ & right justified column content\\ 
       
   447     \hline
       
   448     \verb+c+ & centered column content\\ 
       
   449     \hline
       
   450     \verb+*{n}{col}+ & produces \verb+n+ columns with the\\
       
   451                    & \verb+col+ type of formatting\\
       
   452     \cline{2-2}
       
   453                    &\verb+*{3}{c}+ is the same as \verb+{c c c}+ \\
       
   454     \hline
       
   455     \verb+|+ & produces a vertical line\\ 
       
   456     \hline
       
   457   \end{tabular}
       
   458 
       
   459 Importing Graphics
       
   460 ~~~~~~~~~~~~~~~~~~
       
   461 
       
   462 To include images in LaTeX, we require to use an additional package known as ``graphicx``.  To load a package, we use the ``\usepackage`` directive in the preamble of the document.
       
   463 ::
       
   464 
       
   465   \usepackage{graphicx}
       
   466 
       
   467 When compiling with ``pdflatex`` command,  **jpg**, **png**, **gif** and **pdf** images can be inserted. 
       
   468 
       
   469 ::
       
   470 
       
   471   \includegraphics[optional arguments]{imagename}
       
   472 
       
   473 A few ``optional arguments``:
       
   474 
       
   475   ``width=x``, ``height=x``
       
   476     If only the height or width is specified, the image is scaled, maintaining the aspect ratio.
       
   477 
       
   478   ``keepaspectratio``
       
   479     This parameter can either be set to true or false. When set to true, the image is scaled according to both width and height, without changing the aspect ratio, so that it does not exceed both the width and the height dimensions. 
       
   480 
       
   481   ``scale=x``
       
   482     Scale the image by a factor of ``x``. For example, ``scale=2``, will double the image size. 
       
   483 
       
   484   ``angle=x``
       
   485     This option can be used to rotate the image by ``x`` degrees, counter-clockwise. 
       
   486 
       
   487 ::
       
   488 
       
   489   \includegraphics[scale=0.8, angle=30]{lion_orig.png}
       
   490 
       
   491 Floats
       
   492 ~~~~~~
       
   493 
       
   494 Tables and Figures need to be treated in a special manner, since they cannot be split over pages, and they are referred to as floats in LaTeX. 
       
   495 
       
   496 When there is not enough space on a page, to fit in a table or figure, it is floated over to the next page filling up the current page with text. LaTeX has float environments called table and figure for tables and images, respectively.
       
   497 
       
   498 Anything enclosed within the table or figure environments will be treated as floats.
       
   499 ::
       
   500 
       
   501   \begin{figure}[pos] or 
       
   502   \begin{table}[pos]
       
   503 
       
   504 The ``pos`` parameter specifies the placement of the float. The possible values it can take are as follows. 
       
   505 
       
   506 +-----------+-------------------------------------------------------------------+
       
   507 | Specifier | Permission                                                        |
       
   508 +===========+===================================================================+
       
   509 |   h       |  at approximately the same place where it occurs in the source    |
       
   510 +-----------+-------------------------------------------------------------------+
       
   511 |   t       |  at the top of the page.                                          |
       
   512 +-----------+-------------------------------------------------------------------+
       
   513 |   b       |  at the bottom of the page.                                       |
       
   514 +-----------+-------------------------------------------------------------------+
       
   515 |   p       |  on a special page for floats only.                               |
       
   516 +-----------+-------------------------------------------------------------------+
       
   517 |   !       |  Override LaTeX's internal parameters for good positions          |
       
   518 +-----------+-------------------------------------------------------------------+
       
   519 |   H       |  nearly equivalent to h!                                          |
       
   520 +-----------+-------------------------------------------------------------------+
       
   521 
       
   522 Examples::
       
   523 
       
   524   \begin{figure}[h]
       
   525   \centering
       
   526   \includegraphics[scale=0.8, angle=30]{lion_orig.png}
       
   527   \end{figure}
       
   528 
       
   529 
       
   530 Captions
       
   531 ~~~~~~~~
       
   532 
       
   533 The ``\caption{text}`` command allows you to add captions to images or tables. LaTeX automatically numbers your tables and figures and you need not include numbers in the captions that you write. The caption appears below or on top of the image (or table), depending on whether you place it after or before the ``importgraphics`` (or ``tabular``) command. 
       
   534 
       
   535 ::
       
   536   \begin{figure}[h]
       
   537   \centering
       
   538   \includegraphics[scale=0.8]{lion_orig.png}
       
   539   \caption{CTAN lion drawing by Duane Bibby; thanks to www.ctan.org}
       
   540   \end{figure}
       
   541 
       
   542 The caption command also, like the section command, has the short caption optional parameter. The short caption will appear in the list of tables or figures. 
       
   543 
       
   544 List of Figures, Tables
       
   545 ~~~~~~~~~~~~~~~~~~~~~~~
       
   546 
       
   547 LaTeX can automatically generate a List of Tables or Figures, with the table or figure numbers, the captions and page numbers on which they appear. This can be done using the ``\listoftables`` or ``listoffigures`` commands. 
       
   548 
       
   549 Note: Just like table of contents, these lists also require an extra compilation. 
       
   550 
       
   551 Cross References
       
   552 ~~~~~~~~~~~~~~~~
       
   553 
       
   554 LaTeX has a very efficient mechanism of inserting cross-references in documents. 
       
   555 
       
   556 The command ``\label{name}`` is used to label figures, tables or segments of text. ``\ref{name}`` refers to the object marked by the ``name`` by it's numbering (figure, table, section etc.) ``\pageref{name}`` gives the page number of the object which has been labeled with ``name``. 
       
   557 
       
   558 Note: Cross referencing also requires an extra compilation, like table of contents. 
       
   559 
       
   560 Bibliography
       
   561 ------------
       
   562 
       
   563 Bibliography or references can be added to LaTeX documents in two ways - using the ``thebibliography`` environment, or using BibTeX. Let's first look at using the ``\thebibliography`` environment and then move on to BibTeX.
       
   564 
       
   565 ``thebibliography`` environment
       
   566 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
       
   567 
       
   568 Writing bibliographies in LaTeX using the ``thebibliography`` environment is pretty easy. You simply have to list down all the bibliography items within the bibliography environment. 
       
   569 
       
   570 Each entry of the bibliography begins with the command ``\bibitem[label]{name}``. The name is used to cite the bibliography item within the document using  ``\cite{name}``. The label option replaces the numbers from the auto enumeration with the labels given. 
       
   571 ::
       
   572 
       
   573   He used this lion in the illustrations for D Knuth's original TeXbook\cite{DKnuth}, for L Lamport's LaTeX book\cite{LLamport}
       
   574 
       
   575   \begin{thebibliography}{99}
       
   576     \bibitem{DKnuth} Donald E. Knuth (1984). \emph{The TeXbook} (Computers and Typesetting, Volume A). Reading, Massachusetts: Addison-Wesley. ISBN 0-201-13448-9.
       
   577   
       
   578     \bibitem{LLamport} Lamport, Leslie (1994). \emph{LaTeX: A document preparation system: User's guide and reference}.
       
   579      illustrations by Duane Bibby (2nd ed.). Reading, Mass: Addison-Wesley Professional. 
       
   580   \end{thebibliography}
       
   581 
       
   582 The ``99`` in the example above indicates the maximum width of the label that the references may get. We here assume that the number of Bibliography items will be less than 100. If your document has less than 10 references, you may want to replace ``99`` with ``9``. 
       
   583 
       
   584 BibTeX
       
   585 ~~~~~~
       
   586 
       
   587 The previous section explained the process of listing references at the end of a document and embedding cross references. In this section let us explore the BibTeX environment for keeping track of references.
       
   588 
       
   589 Using BibTeX is a very convenient method to use, when writing multiple documents in a single area or field. BibTeX allows you to create a database of all your references and use them as and when required. 
       
   590 
       
   591 The BibTeX database is stored in a ``.bib`` file. The structure of the file is quite simple and an example is shown below. 
       
   592 ::
       
   593 
       
   594   @book{Lamport94,
       
   595   author    = "Leslie Lamport",
       
   596   title     = "A Document Preparation System: User's Guide and Reference",
       
   597   publisher = "Addison-Wesley Professional",
       
   598   year      = "1994",
       
   599   edition    = "second",
       
   600   note      = "illustrations by Duane Bibby"
       
   601   }
       
   602 
       
   603 Each bibliography entry starts with a declaration of the type of the reference being mentioned. The reference is in the above example is of the book type. BibTeX has a wide range of reference types, for example, ``article, book, conference, manual, proceedings, unpublished``.
       
   604 
       
   605 The type of reference is followed by a left curly brace, and immediately followed by the citation key. The citation key, ``Lamport94`` in the example above is used to cite this reference using the command ``\cite{Lamport94}``. 
       
   606 
       
   607 This is followed by the relevant fields and their values, listed one by one. Each entry must be followed by a comma to delimit one field from the other. 
       
   608 
       
   609 To get your LaTeX document to use the bibliography database, you just add the following lines to your LaTeX document. 
       
   610 ::
       
   611 
       
   612   \bibliographystyle{plain}
       
   613   \bibliography{LaTeX}
       
   614 
       
   615 Bibliography styles are files that tell BibTeX how to format the information stored in the ``.bib`` database file. The style file for this example is ``plain.bst``. Note that you do not need to add the ``.bst`` extension to the filename.  If you wish to achieve a particular style of listing the bibliography items and citing them, you should use an appropriate style file. 
       
   616 
       
   617 The ``bibliography`` command specifies the file that should be used as the database for references. The file used in this example is ``LaTeX.bib``
       
   618 
       
   619 Compiling
       
   620 +++++++++
       
   621 
       
   622 Adding BibTeX based references, slightly complicates the process of compiling the document to obtain the desired output. The exact workings of LaTeX and BibTeX will not be explained here. The procedure for obtaining the output (without any explanations) is as follows:
       
   623 
       
   624 1. Compile the ``.tex`` file using ``pdflatex`` - ``$pdflatex LaTeX(.tex)``
       
   625 2. Compile the ``.bib`` file using ``bibtex`` -  ``$bibtex LaTeX(.bib)``
       
   626 3. Compile the ``.tex`` file again. 
       
   627 4. Compile the ``.tex`` file for one last time!
       
   628 
       
   629 Typesetting Math
       
   630 ----------------
       
   631 
       
   632 It is advisable to use the AMS-LaTeX bundle to typeset mathematics in LaTeX. It is a collection of packages and classes for mathematical typesetting. 
       
   633 
       
   634 We load ``amsmath`` by issuing the ``\usepackage{amsmath}`` in the preamble. Through out this section, it is assumed that the ``amsmath`` package has been loaded. 
       
   635 
       
   636 
       
   637 Math Mode
       
   638 ~~~~~~~~~
       
   639 
       
   640 There are a few differences between the *math mode* and the *text mode*:
       
   641 
       
   642 1. Most spaces and line breaks do not have any significance, as all spaces are either derived logically from the mathematical expressions, or have to be specified with special commands such as ``\``, ``\quad`` or ``\qquad``
       
   643 
       
   644 2. Empty lines are not allowed.  
       
   645 
       
   646 3. Each letter is considered to be the name of a variable and will be typeset as such. If you want to typeset normal text within a formula, then you have to enter the text using the \text{...} command
       
   647 
       
   648 Single Equations
       
   649 ~~~~~~~~~~~~~~~~
       
   650 
       
   651 Mathematical equations can be inserted in-line within a paragraph (*text style*), or the paragraph can be broken to typeset it separately (*display style*). 
       
   652 
       
   653 A mathematical equation within a paragraph is entered between ``$`` and ``$``. Larger equations are set apart from the paragraph, by enclosing them within ``\begin{equation}`` and ``\end{equation}``. If you don't wish to number a particular equation, the starred version of equation can be used. ``\begin{equation*}`` and ``\end{equation*}``
       
   654 
       
   655 The equation can also be cross referenced using the ``\label`` and ``\eqref`` commands. 
       
   656 
       
   657 Basic Elements
       
   658 ~~~~~~~~~~~~~~
       
   659 
       
   660 Greek Letters can are entered as ``\alpha, \beta, \gamma, \delta, ...`` for lowercase letters and ``\Alpha, \Beta, \Gamma, ...`` for uppercase ones. 
       
   661 
       
   662 Exponents and subscripts can be typeset using the carat ``^`` and the underscore ``_`` respectively. Most of the math mode commands act only on the next character. If you want a command to affect several characters, they need to be enclosed in curly braces. 
       
   663 
       
   664 The ``\sqrt`` command is used to typeset the square root symbol. LaTeX of the root sign is determined automatically. The nth root is generated with ``\sqrt[n]``. 
       
   665 
       
   666 To explicitly show a multiplication a dot may be shown. ``\cdot`` could be used, which typesets the dot to the center. ``\cdots`` is three centered dots while ``\ldots`` sets the dots on the baseline. Besides that ``\vdots`` for vertical and ``\ddots`` can be used for diagonal dots.
       
   667 
       
   668 A fraction can be typeset with the command ``\frac{..}{..}``
       
   669 
       
   670 The integral operator is generated with ``\int``, the sum operator with ``\sum``, and the product operator with ``\prod``. The upper and lower limits are specified with ``^`` and ``_`` like subscripts and superscripts.
       
   671 
       
   672 LaTeX provides all kinds of braces as delimiters. The round and square brackets can be produces using the keys on the keyboard and appending a backslash. Other delimiters can be produced using special commands of LaTeX. Placing ``\left`` in front of an opening delimiter and ``\right`` in front of a closing delimiter, instructs LaTeX to automatically take care of the sizes of the delimiters. 
       
   673 
       
   674 Multiple Equations
       
   675 ~~~~~~~~~~~~~~~~~~
       
   676 
       
   677 Long formulae that run over several lines or equation systems, can be typeset using the ``align`` or ``align*`` environments. ``align`` numbers each of the lines in the environment, and ``align*`` as expected, does not number any of them. 
       
   678 
       
   679 The ``&`` is used to align the equations vertically and the ``\\`` command is used to break the lines. Line numbering can be skipped for a particular line in the ``align`` environment by placing a ``\nonumber`` before the line break.
       
   680 
       
   681 ::
       
   682 
       
   683   \begin{align}
       
   684   \alpha^2 + \beta^2 &= \gamma^2 \\
       
   685   \sum_{i=1}^ni &= \frac{n(n+1)}{2}\\
       
   686   \sqrt{-1} &= \pm1 \nonumber
       
   687   \end{align}
       
   688 
       
   689 
       
   690 Arrays and Matrices
       
   691 ~~~~~~~~~~~~~~~~~~~
       
   692 
       
   693 To typeset arrays, use the ``array`` environment. It works similar to the ``tabular`` environment. The ``\\`` command is used to break the lines. 
       
   694 ::
       
   695 
       
   696   \begin{equation*}
       
   697   \mathbf{X} = \left(
       
   698    \begin{array}{ccc}
       
   699    a_1 & a_2 & \ldots \\
       
   700    b_1 & b_2 & \ldots \\
       
   701    \vdots & \vdots & \ddots
       
   702    \end{array} \right)
       
   703   \end{equation*}
       
   704 
       
   705 The ``array`` environment can also be used to typeset piecewise functions by using a “.” as an invisible ``\right`` delimiter
       
   706 ::
       
   707 
       
   708   \begin{equation*}
       
   709   f(x) = \left\{
       
   710    \begin{array}{rl}
       
   711      0 & \text{if } x \le 0\\
       
   712      1 & \text{if } x > 0
       
   713    \end{array} \right.
       
   714    \end{equation*}
       
   715 
       
   716 Six different types of matrix environments are available in the ``amsmath`` package for typesetting matrices.  They essentially have different delimiters: ``matrix`` (none), ``pmatrix`` (, ``bmatrix`` [, ``Bmatrix`` {, ``vmatrix`` | and ``Vmatrix`` ‖. In these matrix environments, the number of columns need not be specified, unlike the ``array`` environment.
       
   717 ::
       
   718 
       
   719   \begin{equation*}
       
   720     \begin{matrix}
       
   721     1 & 2 \\
       
   722     3 & 4
       
   723     \end{matrix} \qquad
       
   724  
       
   725     \begin{bmatrix}
       
   726     1 & 2 & 3 \\
       
   727     4 & 5 & 6 \\
       
   728     7 & 8 & 9
       
   729     \end{bmatrix}
       
   730   \end{equation*}
       
   731 
       
   732 Miscellaneous Stuff
       
   733 -------------------
       
   734 
       
   735 Presentations
       
   736 ~~~~~~~~~~~~~
       
   737 
       
   738 LaTeX has quite a few options to produce presentation slides. We shall look at the ``beamer`` class, which is well developed and easy to use. We shall only briefly look at some of the features of beamer. For the best documentation, look at the beamer user guide.
       
   739 
       
   740 To write a ``beamer`` presentation, it is recommended that you use one of the templates that beamer provides. We shall use the ``speaker_introduction`` template to get started with beamer. 
       
   741 
       
   742 As you can see, the document begins with the ``documentclass`` being set to beamer. 
       
   743 
       
   744 The ``\setbeamertemplate`` command sets the template for various parameters. The ``background canvas``, ``headline`` and ``footline`` are being set using the command.
       
   745 
       
   746 ``\usetheme`` command sets the theme to be used in the presentation. 
       
   747 
       
   748 Notice that each slide is enclosed within ``\begin{frame}`` and ``\end{frame}`` commands. The ``\begin{frame}`` command can be passed the Title and Subtitle of the slide as parameters. 
       
   749 
       
   750 To achieve more with beamer, it is highly recommended that you look at the ``beameruserguide``.
       
   751 
       
   752 Including Code
       
   753 ~~~~~~~~~~~~~~
       
   754 
       
   755 The ``listings`` package can be used to embed source code into your LaTeX document. We shall briefly explore inserting python code into our document. 
       
   756 
       
   757 Obviously, you first need to tell LaTeX that you want it to use the ``listings`` package, using the ``\usepackage`` command. 
       
   758 ::
       
   759 
       
   760   \usepackage{listings}
       
   761 
       
   762 Then, we tell LaTeX that we are going to embed Python code into this document. A simple code highlighting for Python code can be achieved using this. 
       
   763 ::
       
   764 
       
   765   \lstset{language=Python,
       
   766           showstringspaces=false,
       
   767          }
       
   768 
       
   769 You might want to customize the code highlighting further using other variables like ``basicstyle``, ``commentstyle``, ``stringstyle``, ``keywordstyle`` etc. For detailed information on all this, you should look at the ``listings`` package documentation. 
       
   770 
       
   771 You include a block of code into your document by enclosing it within the ``lstlisting`` environment. 
       
   772 ::
       
   773 
       
   774   \begin{lstlisting}
       
   775   string="Hello, World! "
       
   776   for i in range(10):
       
   777       print string*i
       
   778   \end{lstlisting} 
       
   779 
       
   780 You can also include source code files directly into your latex document, using the ``lstinputlisting`` command. 
       
   781 ::
       
   782 
       
   783   \lstinputlisting[lastline=20]{lstexample.py}
       
   784 
       
   785 This command includes the first 20 lines of the file ``lstexample.py`` into out LaTeX document. 
       
   786 
       
   787 Including files
       
   788 ~~~~~~~~~~~~~~~
       
   789 When working on a large document, it is convenient sometimes, to split the large file into smaller input files and club them together at the time of compiling. 
       
   790 
       
   791 The ``\input`` or ``\include`` commands may be used to embed one LaTeX file into another. The ``\input`` command is equivalent to a copy and paste of the document, just before the compilation. The ``\include`` command is exactly similar, except for the fact that it creates a new page every time it is issued.
       
   792 
       
   793 ``\input{file}`` or ``\include{file}`` commands will include the file ``file1.tex`` with in the file where the command has been issued. Note that you do not need to specify the ``.tex`` extension of the file. 
       
   794 
       
   795 The ``\includeonly`` is useful for debugging or testing the LaTeX document that you are creating, since it restricts the ``\include`` command. Only the files which are given as arguments to the ``\includeonly`` command will be included in the document (wherever a ``\include`` command for those files, has been issued).
       
   796 
       
   797 A note on filenames
       
   798 +++++++++++++++++++
       
   799 
       
   800 Never use filenames or directories that contain spaces. Make filenames as long or short as you would like, but strictly avoid spaces. Stick to upper or lower case letters (without accents), the digits, the hyphen and the full stop or period.
       
   801 
       
   802 
       
   803 
       
   804 Recommended Reading
       
   805 -------------------
       
   806 
       
   807 1. *LaTeX Wikibook*
       
   808 
       
   809 2. *The Not So Short Introduction to LaTeX2e* by Tobias Oetikar et al.. 
       
   810 
       
   811