EGR 53L - Spring 2011

Transcription

1 EGR 53L - Spring 2011 Appendix A LATEX Information A.1 Introduction L A TEX is a very useful tool for making your lab reports look great. This document contains information about creating L A TEX documents, useful commands, and processing files. When you see text written in typewriter font, that means you can type it directly as you see it written here. A.2 Setting up the Document A.2.1 Using AMS-TEX The AMS-TEX package is included in OIT s basic L A TEX suite. This package, from the American Mathematical Society, contains several commands that make typesetting mathematics easier. While this guide will not always indicate which tools are from this package, you should note that some distributions of L A TEX must have the AMS-TEX package installed separately. A.2.2 Creating a L A TEX Document L A TEX runs by reading code that has been typed into a text editor. You will be creating a text document that contains all the code L A TEX needs to process the document. You can use any text editor you want (Pico, VI, Emacs, gedit, etc.) to create L A TEX code, though in this document we will be using Emacs. A L A TEX file must be saved with the ending of.tex. As an example, let s say we want to name our file lab1. In other words, the base name of the file (i.e. the file name without any of the extensions) will be lab1. To open Emacs and create this file, in the terminal window type next to your NET ID type: emacs lab1.tex & and press enter. The purpose of the & is to allow you to continue issuing commands in the terminal window. This will become helpful later when you are ready to view your document. If you forgot the & then you should close Emacs and re-run the command above. If you want to open your file again later, use the same command as above: emacs followed by the name of the file ending in.tex. Make sure you are in the right UNIX directory. A.2.3 Command Basics When Emacs opens, you will see a (mostly) blank page unless the file you have opened already has text in it. In that case, you should see the contents of that file. If you were expecting text, and see a blank page instead, you have likely either spelled the name of the file incorrectly or you are in the wrong directory. Be sure that you have the correct file before continuing. Now you can begin typing your commands. Most of the code in a L A TEX document consists of a series of commands. These commands consist of a backslash (\) followed by a word or phrase, and often another word, phrase, or number in brackets ({ }). When you type a command, or even just a backslash, it may appear in a different color or font style. Emacs has some helpful formatting commands that work with L A TEX code - these will be described later. When the command includes a backslash followed by begin, we say that we have initiated an environment. An environment is treated differently from the other text, depending on what you tell it to do. An environment is terminated with backslash followed by end. For example: \begin{document} \begin{center} text \end{center} \end{document} Other commands simply include a backslash and a symbol or word: \LaTeX \Delta \& App A 1

2 Note that in order to leave a space after the L A TEX symbol, you need to use the space command, which is simply a slash followed by a space. Punctuation that comes after L A TEX, however, works fine for L A TEX. The previous sentences, for example, were generated by: Note that in order to leave a space after the \LaTeX\ symbol, you need to use the space command, which is simply a slash followed by a space. Punctuation that comes after \LaTeX, however, works fine for \LaTeX. A.2.4 The Beginning and Ending of a L A TEX Document To start a document, you need to give L A TEX some information. The first code you need in your document is the header. The commands in the header will tell L A TEX what kind of document you have, whether you want to load any additional commands, and various other pieces of information that L A TEX needs before the body of the document appears. The simplest header indicates nothing more than what class of document you are creating and then tells L A TEX that the document is about to begin: \documentclass{article} \begin{document} In order to certain commands or to change the overall look and feel of a document, however, there may be a much more involved header. For example: \documentclass{article} \usepackage{amsmath} % loads AMS-Math package \usepackage{epsfig} % allows PostScript files \usepackage{listings} % allows lstlisting environment \usepackage{moreverb} % allows listinginput environment \usepackage{vmargin} % allows better margins \setpapersize{usletter} % sets the paper size \setmarginsrb{1in}{0.5in}{1in}{0.2in}{12pt}{11mm}{0pt}{11mm} % sets margins \begin{document} When you are finished adding the code required for a document, the last line should be: \end{document} This tells L A TEX that the document is done and it can stop processing the.tex file. Given that, the shortest L A TEX document you could have would be: \documentclass{article} \begin{document} a \end{document} which would produce a document of class article containing only the letter a. Note that simply writing and saving the.tex file will not create the finished document - that process will be covered in Section A.4 on page App A 10. App A 2

3 A.3 Frequently Used Commands A.3.1 Verbatim Environments You will have several occasions to include text directly from some other source in your reports. There are several different options for how to include that text in your file. First, you can use the verbatim environment. Characters placed between the begin and end tags of a verbatim environment are reproduced in your L A TEX document without L A TEX trying to process them for commands. That is to say, the code: \begin{verbatim} \documentclass{article} \begin{document} a \end{document} \end{verbatim} will be rendered as follows: \documentclass{article} \begin{document} a \end{document} At this point, you may be asking yourself, How can you get the \end{verbatim} text to still be inside a verbatim environment? And the answer is - you can t. In this particular case, a different verbatim-like environment was used. This environment - calledlstlisting - is not a part of the default L A TEX distribution but may be added to it using the \usepackage{listings} command in the header. The lstlisting command has some features that make it a bit more flexible than the verbatim command - for example, the ability to put a box around the text: Text. In a box. or to put a shadowbox around the text: Text. In a shadowbox. The box and shadowbox above was generated with the code: \begin{lstlisting}[frame=single] Text. In a box. \end{lstlisting} and \begin{lstlisting}[frame=shadowbox] Text. In a shadowbox. \end{lstlisting} Of course, things brings up the question of how the text above was typeset - and the answer is, in a verbatim environment. 1 1 You may be asking now, what if you want to show the code in LATEX that would put a verbatim environment inside a lstlisting environment inside a verbatim environment? To which a common reply might be another question - why on Earth would you want to do that?? App A 3

4 A.3.2 Copying / Inserting Text from Files If the information you want to have included in your document is currently residing in a file, there are two fundamentally different ways to bring them into your report. The first is to cut-and-paste the information into a verbatim or lstlisting environment. And there are two different ways to cut-and-paste. The first would be to literally 2 cut-and-paste the information. Open the document with the data you want transferred, select the information you want, then paste it into your.tex file. On UNIX, this generally means click-hold-dragging around the information you want, left-clicking in the.tex document, then middle clicking. The second method of cut-and-paste is to use Emacs Insert File command. With it, you can have Emacs bring all the data from one file into your.tex document. The Insert File command is located in the File command list at the top of the Emacs window. After you issue the command, you will need to type the address of the file you would like inserted. For example, to insert the code from the.m file MyFile.m which is in your EGR53 lab2 directory, go to Insert File and type: ~/EGR53/lab2/MyFile.m in the mini-command window that Emacs has activated. The text of the.m file will now appear in your document. A.3.3 Importing Text from Files Finally, if you want to bring in all the data from a file, you can use a special L A TEX command to have it import the information from a file as you process the document. In other words, this method does not require that you cut-and-paste the information but rather that you tell L A TEX what file to get the information from. There are two main commands to do this. The first is the verbatiminput command, which will basically take whatever is in the file specified and duplicate it in your document as if the characters were in averbatim environment. The format for this command is: \verbatiminput{myfile} Many times, you will be importing codes or scripts. And when importing codes or scripts, you will often find it convenient to have the line numbers printed along side the code. One of the most useful commands to do this is the listinginput command. This command is not a part of standard L A TEX but may be loaded with \usepackage{moreverb} in the header of a document. The simplest format for this command is: \listinginput[1]{1}{myfile} where the [1] means to put a line number on each line and the {1} means to start numbering at 1. You can change the number in the square brackets if you only want the line numbers printed every few lines. You can change the number in the curly brackets if the first line of the imported file should be listed as something other than 1. Note that the lstlisting command will always put a 1 on line 1 if such a line exists (i.e. as long as the number in the curly brackets is 1 or smaller). Also, the line numbers that are printed, other than 1 as mentioned, will be the integer multiples of the number in the square brackets. For example, the command: \listinginput[3]{-5}{myfile} means the first line of the file is numbered -5 and print line numbers for lines that are multiples of 3 and for whichever line is numbered 1. If the file is long enough, then the first two imported lines would have no number printed (they would be numbered -5 and -4 by lstlisting); the next imported line, numbered -3, would have its line number printed. The next two imported lines, numbered -2 and -1, would not. The sixth line of code - numbered 0 - would have its number printed next to it, as would the seventh line of code since it is numbered 1 and listinginput always prints the 1. From there on out, only lines numbered as integer multiples of 3 would have their numbers printed. 2 Well...literally in the computational senses of cut and paste. App A 4

5 A.3.4 Math Mode To write the L A TEX for most of the mathematical symbols, formulas, and other constructions you want to create, such as Greek letters, arrows, relational symbols, and so on, you are going to need to be in math mode. Otherwise, L A TEX gets stuck and the symbol does not appear as you intended. In addition, arrays must be created in math mode. There are a couple of ways to get into math mode. If you want to put math in the middle of a phrase or sentence - for example, a single letter, exponent or formula - it is easiest to surround the text with dollar signs ($). Consider the following sentence: We calculated the stress as σ = MPa and the strain as ǫ = 1.2. This is how the code appeared: We calculated the stress as $\sigma = 1.6 \times 10^6$ MPa and the strain as $\epsilon = 1.2$.\\ You do not want to surround the whole sentence with the $ symbols, because it will appear like this: Wecalculatedthestressasσ = MPaandthestrainasǫ = 1.2. You can use the $ symbol to get into math mode for larger expressions as well, though if the expression should be set on its own you will want to use a specialized math environment. For example, it may be a bit awkward to write that the Law of Cosines, which states that, a 2 + b 2 = c 2 2ab cos(θ), can be solved a b c ( ) c for θ with θ = arccos 2 a 2 b 2 2ab. Or that the determinant of a matrix M = d e f is det(m) = g h i aei + bfg + cdh afh bdi ceg. Generally, anything taller than a typical line of text should go on its own as not to interfere with the line spacing. A.3.5 Math Environments L A TEX itself provides several math environments, while theamsmath package adds several more. The following commands show different ways to start a math environment. Note that since they are math environments in their own right, they do not get surrounded by $. \begin{eqnarray} \end{eqnarray} The eqnarray environment is the built-in environment for getting a numbered array of equations. For example, to typeset the equations: you would need to have: \begin{eqnarray} ax^2+bx+c=0\\ x=\frac{-b\pm\sqrt{b^2-4ac}}{2a} \end{eqnarray} ax 2 + bx + c = 0 x = b ± b 2 4ac 2a (A.1) (A.2) as a part of your.tex document. The begin command is used to start the eqnarray environment which accepts an array of equations. Note that the equations are both right-justified and each line is numbered. App A 5

6 \begin{eqnarray*} \end{eqnarray*} Most math environments come in numbered and unnumbered forms. To typeset the same equations above, but without equation numbers: you could use: \begin{eqnarray*} ax^2+bx+c=0\\ x=\frac{-b\pm\sqrt{b^2-4ac}}{2a} \end{eqnarray*} ax 2 + bx + c = 0 x = b ± b 2 4ac 2a where the asterisk is an indicator to L A TEX not to number each line. \begin{align} \end{align} Using the AMS-TEX package - and specifically the align environment that it provides - you can line equations up on particular characters. You will need to put an & before the character that you aligned. Example: This is generated using: ax 2 + bx + c = 0 \begin{align} ax^2+bx+c&=0\\ x&=\frac{-b\pm\sqrt{b^2-4ac}}{2a} \end{align} x = b ± b 2 4ac 2a % <-- note location of & (A.3) (A.4) The equations are lined up on whatever comes after the ampersand and the equations are numbered (no asterisk after align). Note that the numbering is a continuation of the numbering from the eqnarray environment - but that there was no increase in the equation number from the equations in the eqnarray* environment. \begin{align*} \end{align*} This time the * suppresses numbering of the equations. Example: The code for this is: 3x + 4y = 10 a(x x 0 ) + b(y y 0 ) + c(z z 0 ) = 0 \begin{align*} 3x + 4y &= 10\\ a(x-x_{0}) +b(y-y_{0})+c(z-z_{0})&=0 \end{align*} Both align environments will center the group of equations. App A 6

7 Multiple equations per line You can include multiple equations on a single line in the align and align* environments, using & to separate the different equations. Example: The code for this is: \begin{align} \pi&= & e&= \\ i&=\sqrt{-1} & e^{\pi i}&=-1 \end{align} π = e = (A.5) i = 1 e πi = 1 (A.6) Finally, you will sometimes want to have parts of an eqnarray or align environment numbered and other parts not. For example, if a portion of an equations runs several lines, you might want the first one numbered but the other not. In this case, you can append a \nonumber to the end of whichever lines should remain unnumbered. For example: Fx = F 1 + F 2 + F 5 (A.7) is created with: = 100 lb + ( 20 lb) + 50 lb = 130 lb Fy = F 3 F 4 = 140 lb 30 lb = 110 lb \begin{align} \sum F_x&=F_1+F_2+F_5\\ &= 100\mbox{ lb}+(-20\mbox{ lb})+50\mbox{ lb} \nonumber \\ &= 130\mbox{ lb} \nonumber \\ \sum F_y&=F_3-F_4\\ &= 140\mbox{ lb}-30\mbox{ lb} \nonumber \\ &= 110\mbox{ lb} \nonumber \end{align} (A.8) App A 7

8 A.3.6 General Math Commands These require math mode - which is to say, either the code they are in needs to be surrounded by $ or inside a math environment as described above. \frac{a}{b} Creates the fraction a b ; replace a and b with anything. \mbox{text} When you want text to appear normal within an equation, instead of using italics and math spacing. \lim, \hat{a}, \vec{a}, \imath, \jmath, \sqrt{a} A couple of other useful commands; you might be able to guess what they do. If not, let a search engine do the walking! Or try them out in your own file. _{subscript}, ^{superscript} Subscripts and superscripts - the brackets are optional for single character subscripts and superscripts but required for multiple characters. \lefta B \rightc- used to put brackets of symbols A and C to the left and right of whatever B is. A and C do not have to be the same thing, but there does have to be a right for every left. The possible symbols are in Kopka and Daly. An additional symbol is the period (.), which will produce a blank - this is useful if you want to only have a delimiter on one side. One thing to be careful about is using curly brackets {} as delimiters. You must put a slash in front of them first. For example: 0 x < 0 f(x) = undefined x = 0 g(x) = = 2 1 x > 0 can be produced with the code: \begin{align*} f(x)&=\left\{ \begin{array}{ll} 0 & x<0 \\ \mbox{undefined} & x=0\\ 1 & x>0 \end{array} \right.& g(x)&=\left \left[ \begin{array}{cc} 1 & 2 \\ 3 & 4 \end{array} \right] \right &=-2 \end{align*} % <-- note slash in front of curly bracket % <-- note the dot which produces a blank The use of superscripts, subscripts, special symbols, and fractions are all covered in the Kopka and Daly book. The exercises given at the end of some of the articles are good for learning how to produce mathematical equations. Some of them, however, depend on knowledge of functions covered in earlier sections. App A 8

9 A.3.7 Additional Commands This is a brief list of the commands you are going to need frequently when writing lab reports. In addition, the index and appendices of Kopka and Daly as well as many web sites are excellent resources. Spacing Commands \\: The equivalent to the return key; two backslashes will move to the next line. You can also add a number after the backslash: \\[0.5 cm]. This will create a space of 0.5 cm between the two lines. Another way to create extra space between lines is \\. If you want to insert a space between two words, use \ followed by a blank space, or simply type between the two words. Page Setup Commands \pagebreak or \newpage: Moves to the next page \begin{center}, \end{center} Centers text. You can probably predict what happens if you replace center with left or right. \section*{your Section Heading} Allows you to create headings for your report, such as Introduction, Discussion, etc. The purpose of the * is to suppress the numbering of the headings. \begin{enumerate}, \begin{itemize} These initiate a listing environment. Enumerate includes numbering, while itemize includes bullets and dashes. Each numbered or bulleted item will begin with the command \item. The lists can also be nested. Make sure you finish with \end{enumerate} or \end{itemize}. Changing the appearance of font {\Large }, {\small }, {\large }... Refer to your text on the various options for changing the size of font. Place the text you want to size within brackets. {\it }, {\sl }, {\bf }, {\tt }... Again, the various styles of font are included in your text. Note: Make sure the brackets are around the whole command, not just the words you want to change. For example: Bold and Italics are good ways to emphasize text. The code for this is: {\bf Bold} and {\it Italics} are good ways to emphasize text. App A 9

10 A.4 Processing a File Processing a L A TEX file can be tedious, but it is important not to skip any steps until you are more comfortable with how L A TEX works. You can create a paper copy from a L A TEX document as follows: Create and Save When you have typed in a couple of lines in your file name.tex, where name is any file name of your choosing, and you want to see how they look, click Save in Emacs. Run L A TEX Return to the terminal window and run L A TEX on the file by typing latex name.tex (if no file called name exists, you can also just run latex name). For example, to process the file titled lab1.tex, type: latex lab1.tex L A TEX will get stuck sometimes You will see the terminal window run a number of lines. If it stops without returning you to the command prompt, there is an error in the document. You may see something like this:! File ended while scanning use of \textnormal. <inserted text> \par <*> latex guide? This means that L A TEX was unhappy with something you typed in. Often it will provide the line number (L.29 for example), and you can use Emacs to go to that line and try to find the problem. The message above means that a bracket was omitted at the end of a passage. In the terminal window, type x next to the question mark. This will make L A TEX stop running. If L A TEX quit because you didn t specify a file (i.e. you just typed latex at the command line with no input file) or because it could not find the file you were trying to process (for example, you typed labb1.tex instead of lab1.tex) hit CTRL-d to cancel out of L A TEX. If L A TEX stops for any other reason, type CTRL-c to make L A TEX bring up the question mark. You can then use the x to get out. Fix your mistakes and try again Return to the Emacs window and try to correct your document. Remember to click Save after each change is made. Repeat the steps above until there is no error. You will see: Transcript written on lab1.log. This means that you were successful. The.dvi file L A TEX creates a device independent - or dvi - file. The kdvi program can create a graphical version of this file so you can edit your document without wasting paper. Be aware that there are some types of graphics the kdvi cannot properly display - this will come out of the printer properly, however. Viewing the file with kdvi Run the file using kdvi name.dvi & (again, if no file named name exists, kdvi name). In the current example, name would be lab1: kdvi lab1.dvi & Correct errors Be thorough in checking your document for mistakes. If you find errors, you can automatically make correct them in the Emacs file since it is still open. Rerun L A TEX. Note that if kdvi is still running, it will always bring up the most current copy of the dvi file; you will not need to run a new kdvi unless you closed the previous one. App A 10

11 Printing Most of the time, you can just print directly from kdvi. When you click the printer button, there will be a printer name selection at the top of the screen - you will want to choose lp0 - that is the name for the eprint queue. Creating PostScript file The printer does not understand dvi files, only PostScript files, and sometimes kdvi cannot translate the information properly. In those cases, the dvips program will convert a dvi file to a PostScript file. The default setting for the program, however, is to send the new PostScript file directly to the printer. You will want to edit your file one last time, so it is better to create a PostScript file, look at it again, then send it to the printer yourself. You can do this using the command dvips -o newname name.dvi (if no file called name exists, dvips -o newname name). The -o tells the program to produce an output PostScript file called newname. If the -o newname is omitted, the PostScript will be sent directly to the printer. If just the newname is omitted, the output file will be called name.ps. Command dvips foo.dvi dvips foo.dvi -o dvips foo.dvi -o bar.ps What it does prints the dvi file converts foo.dvi to postscript and creates a file called foo.ps converts foo.dvi to postscript and creates a file called bar.ps Printing Finally, when you actually want to make a hard copy of your file, you have several options. You can print from kdvi, you can let dvips do the work as in the first example above, you can use the lpr command on a postscript file that has been created by dvips, or you can use the kghostview postscript viewer to look at the file and then print it through there. To get something to print to your room, you need to use dvips to create a PostScript file, use a file transfer program to copy the file from your OIT account to your personal computer and use GhostView on your personal computer to send the PostScript file to your printer. Since most people have not installed postscript viewers on their computer, you can use the PDF format instead. To do this, replace the dvips step above with the dvipdf command. This will create a PDF file that Adobe Acrobat can read. You can then transfer this file to your personal computer using a file transfer program and open and print it using the Acrobat Reader. A.5 Summary of L A TEX Process The following table summarizes the process for a file called lab1.tex to generate a PostScript file called lab1print.ps: Command emacs lab1.tex & (write and save file) latex lab1.tex kdvi lab1.dvi & (print from kdvi) dvips lab1.dvi -o lab1print.ps kghostview lab1print.ps Purpose start text processing program save file within text processing program process L A TEX file - may need to run this three (or four!) times view processed L A TEX file you may be able to just print from here. If not create PostScript file view PostScript file and print If you end up using commands for labels and references (such as \label{}, \ref{}, and \pageref{}), you may actually have to run the L A TEX step three times! The first time L A TEX goes through and figures out what all the labels mean, the second time it can figure out where they are, and the third time it can replace the references with their labels. In fact, running L A TEX a fourth time makes sure that any changes in page numbers caused by entering the page numbers themselves will be taken into account. App A 11